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Text File | 1993-04-03 | 308.7 KB | 8,229 lines

Interrupt List, part 3 of 8 This compilation is Copyright (c) 1989,1990,1991,1992,1993 Ralf Brown --------B-1B--------------------------------- INT 1B C - KEYBOARD - CONTROL-BREAK HANDLER Desc: this interrupt is automatically called when INT 09 determines that Control-Break has been pressed Note: normally points to a short routine in DOS which sets the Ctrl-C flag, thus invoking INT 23h the next time DOS checks for Ctrl-C. SeeAlso: INT 23 --------B-1C--------------------------------- INT 1C - TIME - SYSTEM TIMER TICK Desc: this interrupt is automatically called on each clock tick by the INT 08 handler Notes: this is the preferred interrupt to chain when a program needs to be invoked regularly not available on NEC 9800-series PCs SeeAlso: INT 08 --------B-1D--------------------------------- INT 1D - SYSTEM DATA - VIDEO PARAMETER TABLES Note: default parameter table at F000h:F0A4h for 100% compatible BIOSes SeeAlso: INT 10/AH=00h Format of video parameters: Offset Size Description 00h 16 BYTEs 6845 register values for modes 00h and 01h 10h 16 BYTEs 6845 register values for modes 02h and 03h 20h 16 BYTEs 6845 register values for modes 04h and 05h 30h 16 BYTEs 6845 register values for modes 06h and 07h 40h WORD bytes in video buffer for modes 00h and 01h 42h WORD bytes in video buffer for modes 02h and 03h 44h WORD bytes in video buffer for modes 04h and 05h 46h WORD bytes in video buffer for modes 06h and 07h 48h 8 BYTEs columns on screen for each of modes 00h through 07h 50h 8 BYTEs CRT controller mode bytes for each of modes 00h through 07h --------B-1E--------------------------------- INT 1E - SYSTEM DATA - DISKETTE PARAMETERS Note: default parameter table at F000h:EFC7h for 100% compatible BIOSes SeeAlso: INT 13/AH=0Fh,INT 41 Format of diskette parameter table: Offset Size Description 00h BYTE first specify byte bits 7-4: step rate bits 3-0: head unload time (0Fh = 240 ms) 01h BYTE second specify byte bits 7-1: head load time (01h = 4 ms) bit 0: non-DMA mode (always 0) 02h BYTE delay until motor turned off (in clock ticks) 03h BYTE bytes per sector (00h = 128, 01h = 256, 02h = 512, 03h = 1024) 04h BYTE sectors per track 05h BYTE length of gap between sectors (2Ah for 5.25", 1Bh for 3.5") 06h BYTE data length (ignored if bytes-per-sector field nonzero) 07h BYTE gap length when formatting (50h for 5.25", 6Ch for 3.5") 08h BYTE format filler byte (default F6h) 09h BYTE head settle time in milliseconds 0Ah BYTE motor start time in 1/8 seconds --------B-1F--------------------------------- INT 1F - SYSTEM DATA - 8x8 GRAPHICS FONT Desc: this vector points at 1024 bytes of graphics data, 8 bytes for each character 80h-FFh Note: graphics data for characters 00h-7Fh stored at F000h:FA6Eh in 100% compatible BIOSes SeeAlso: INT 10/AX=5000h,INT 43 --------O-20--------------------------------- INT 20 - Minix - SEND/RECEIVE MESSAGE AX = process ID of other process BX -> message CX = 1 send 2 receive 3 send&receive Note: the message contains the system call number (numbered as in V7 Unix(tm)) and the call parameters --------D-20--------------------------------- INT 20 - DOS 1+ - TERMINATE PROGRAM CS = PSP segment Return: never Note: (see INT 21/AH=00h) SeeAlso: INT 21/AH=00h,INT 21/AH=4Ch --------G-20--------------------------------- INT 20 - COMTROL HOSTESS i/ISA DEBUGGER - INVOKE FIRMWARE DEBUGGER ??? Return: ??? SeeAlso: INT 21"COMTROL HOSTESS" --------G-21--------------------------------- INT 21 - COMTROL HOSTESS i/ISA DEBUGGER - GET SEGMENT FOR CONTROL PROGRAM USE ??? Return: AX = first segment available for control program use SeeAlso: INT 20"COMTROL HOSTESS",INT 22"COMTROL HOSTESS" --------D-2100------------------------------- INT 21 - DOS 1+ - TERMINATE PROGRAM AH = 00h CS = PSP segment Notes: Microsoft recomments using INT 21/AH=4Ch for DOS 2+ execution continues at address stored in INT 22 after DOS performs whatever cleanup it needs to do if the PSP is its own parent, the process's memory is not freed; if INT 22 additionally points into the terminating program, the process is effectively NOT terminated not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=26h,AH=31h,AH=4Ch,INT 20,INT 22 --------D-2101------------------------------- INT 21 - DOS 1+ - READ CHARACTER FROM STANDARD INPUT, WITH ECHO AH = 01h Return: AL = character read Notes: ^C/^Break are checked, and INT 23 executed if read character is echoed to standard output standard input is always the keyboard and standard output the screen under DOS 1.x, but they may be redirected under DOS 2+ SeeAlso: AH=06h,AH=07h,AH=08h,AH=0Ah --------D-2102------------------------------- INT 21 - DOS 1+ - WRITE CHARACTER TO STANDARD OUTPUT AH = 02h DL = character to write Return: AL = last character output (despite the official docs which state nothing is returned) (at least DOS 3.3-5.0) Notes: ^C/^Break are checked, and INT 23 executed if pressed standard output is always the screen under DOS 1.x, but may be redirected under DOS 2+ the last character output will be the character in DL unless DL=09h on entry, in which case AL=20h as tabs are expanded to blanks SeeAlso: AH=06h,AH=09h --------D-2103------------------------------- INT 21 - DOS 1+ - READ CHARACTER FROM STDAUX AH = 03h Return: AL = character read Notes: keyboard checked for ^C/^Break, and INT 23 executed if detected STDAUX is usually the first serial port SeeAlso: AH=04h,INT 14/AH=02h,INT E0/CL=03h --------D-2104------------------------------- INT 21 - DOS 1+ - WRITE CHARACTER TO STDAUX AH = 04h DL = character to write Notes: keyboard checked for ^C/^Break, and INT 23 executed if detected STDAUX is usually the first serial port if STDAUX is busy, this function will wait until it becomes free SeeAlso: AH=03h,INT 14/AH=01h,INT E0/CL=04h --------D-2105------------------------------- INT 21 - DOS 1+ - WRITE CHARACTER TO PRINTER AH = 05h DL = character to print Notes: keyboard checked for ^C/^Break, and INT 23 executed if detected STDPRN is usually the first parallel port, but may be redirected under DOS 2+ if the printer is busy, this function will wait SeeAlso: INT 17/AH=00h --------D-2106------------------------------- INT 21 - DOS 1+ - DIRECT CONSOLE OUTPUT AH = 06h DL = character (except FFh) Return: AL = character output (despite official docs which state nothing is returned) (at least DOS 3.3-5.0) Notes: does not check ^C/^Break writes to standard output, which is always the screen under DOS 1.x, but may be redirected under DOS 2+ SeeAlso: AH=02h,AH=09h --------D-2106--DLFF------------------------- INT 21 - DOS 1+ - DIRECT CONSOLE INPUT AH = 06h DL = FFh Return: ZF set if no character available ZF clear if character available AL = character read Notes: ^C/^Break are NOT checked if the returned character is 00h, the user pressed a key with an extended keycode, which will be returned by the next call of this function reads from standard input, which is always the keyboard under DOS 1.x, but may be redirected under DOS 2+ SeeAlso: AH=0Bh --------D-2107------------------------------- INT 21 - DOS 1+ - DIRECT CHARACTER INPUT, WITHOUT ECHO AH = 07h Return: AL = character read from standard input Notes: does not check ^C/^Break standard input is always the keyboard under DOS 1.x, but may be redirected under DOS 2+ if the interim console flag is set (see AX=6301h), partially-formed double-byte characters may be returned SeeAlso: AH=01h,AH=06h,AH=08h,AH=0Ah --------D-2108------------------------------- INT 21 - DOS 1+ - CHARACTER INPUT WITHOUT ECHO AH = 08h Return: AL = character read from standard input Notes: ^C/^Break are checked, and INT 23 executed if detected standard input is always the keyboard under DOS 1.x, but may be redirected under DOS 2+ if the interim console flag is set (see AX=6301h), partially-formed double-byte characters may be returned SeeAlso: AH=01h,AH=06h,AH=07h,AH=0Ah,AH=64h --------D-2109------------------------------- INT 21 - DOS 1+ - WRITE STRING TO STANDARD OUTPUT AH = 09h DS:DX -> '$'-terminated string Return: AL = 24h (the '$' terminating the string, despite official docs which state that nothing is returned) (at least DOS 3.3-5.0) Notes: ^C/^Break are checked, and INT 23 is called if either pressed standard output is always the screen under DOS 1.x, but may be redirected under DOS 2+ under the FlashTek X-32 DOS extender, the pointer is in DS:EDX SeeAlso: AH=02h,AH=06h"OUTPUT" --------D-210A------------------------------- INT 21 - DOS 1+ - BUFFERED INPUT AH = 0Ah DS:DX -> buffer (see below) Return: buffer filled with user input Notes: ^C/^Break are checked, and INT 23 is called if either detected reads from standard input, which may be redirected under DOS 2+ if the maximum buffer size (see below) is set to 00h, this call returns immediately without reading any input SeeAlso: AH=0Ch,INT 2F/AX=4810h Format of input buffer: Offset Size Description 00h BYTE maximum characters buffer can hold 01h BYTE (input) number of chars from last input which may be recalled (return) number of characters actually read, excluding CR 02h N BYTEs actual characters read, including the final carriage return --------K-210A00----------------------------- INT 21 - WCED v1.6 - INSTALLATION CHECK AX = 0A00h DS:DX -> 6-byte buffer whose first two bytes must be 00h Return: buffer offset 02h-05h filled with "Wced" if installed Program: WCED is a free command-line editor and history utility by Stuart Russell SeeAlso: AH=FFh"CED" --------D-210B------------------------------- INT 21 - DOS 1+ - GET STDIN STATUS AH = 0Bh Return: AL = 00h if no character available = FFh if character is available Notes: ^C/^Break are checked, and INT 23 is called if either pressed standard input is always the keyboard under DOS 1.x, but may be redirected under DOS 2+ if the interim console flag is set (see AX=6301h), this function returns AL=FFh if a partially-formed double-byte character is available SeeAlso: AH=06h"INPUT",AX=4406h --------v-210B56----------------------------- INT 21 - VIRUS - "Perfume" - INSTALLATION CHECK AX = 0B56h Return: AX = 4952h if resident SeeAlso: AX=0D20h --------D-210C------------------------------- INT 21 - DOS 1+ - FLUSH BUFFER AND READ STANDARD INPUT AH = 0Ch AL = STDIN input function to execute after flushing buffer other registers as appropriate for the input function Return: as appropriate for the specified input function Note: if AL is not one of 01h,06h,07h,08h, or 0Ah, the buffer is flushed but no input is attempted SeeAlso: AH=01h,AH=06h"INPUT",AH=07h,AH=08h,AH=0Ah --------D-210D------------------------------- INT 21 - DOS 1+ - DISK RESET AH = 0Dh Notes: writes all modified disk buffers to disk, but does not update directory information (that is only done when files are closed or a SYNC call is issued) SeeAlso: AX=5D01h,INT 13/AH=00h,INT 2F/AX=1120h --------v-210D20----------------------------- INT 21 - VIRUS - "Crazy Imp" - INSTALLATION CHECK AX = 0D20h Return: AX = 1971h if resident SeeAlso: AX=0B56h,AH=30h/DX=ABCDh --------D-210E------------------------------- INT 21 - DOS 1+ - SELECT DEFAULT DRIVE AH = 0Eh DL = new default drive (00h = A:, 01h = B:, etc) Return: AL = number of potentially valid drive letters Notes: under Novell NetWare, the return value is always 32, the number of drives that NetWare supports under DOS 3+, the return value is the greatest of 5, the value of LASTDRIVE= in CONFIG.SYS, and the number of drives actually present on a DOS 1.x/2.x single-floppy system, AL returns 2 since the floppy may be accessed as either A: or B: otherwise, the return value is the highest drive actually present DOS 1.x supports a maximum of 16 drives, 2.x a maximum of 63 drives, and 3+ a maximum of 26 drives SeeAlso: AH=19h,AH=3Bh,AH=DBh --------D-210F------------------------------- INT 21 - DOS 1+ - OPEN FILE USING FCB AH = 0Fh DS:DX -> unopened File Control Block (see below) Return: AL = status 00h successful FFh file not found or access denied Notes: (DOS 3.1+) file opened for read/write in compatibility mode an unopened FCB has the drive, filename, and extension fields filled in and all other bytes cleared not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=10h,AH=16h,AH=3Dh Format of File Control Block: Offset Size Description -7 BYTE extended FCB if FFh -6 5 BYTEs reserved -1 BYTE file attribute if extended FCB 00h BYTE drive number (0 = default, 1 = A, etc) 01h 8 BYTEs blank-padded file name 09h 3 BYTEs blank-padded file extension 0Ch WORD current block number 0Eh WORD logical record size 10h DWORD file size 14h WORD date of last write (see AX=5700h) 16h WORD time of last write (see AX=5700h) (DOS 1.1+) 18h 8 BYTEs reserved (see below) 20h BYTE record within current block 21h DWORD random access record number (if record size is > 64 bytes, high byte is omitted) Note: to use an extended FCB, you must specify the address of the FFh flag at offset -7, rather than the address of the drive number field Format of reserved field for DOS 1.0: Offset Size Description 16h WORD location in directory (if high byte = FFh, low byte is device ID) 18h WORD number of first cluster in file 1Ah WORD current absolute cluster number on disk 1Ch WORD current relative cluster number within file (0 = first cluster of file, 1 = second cluster, etc.) 1Eh BYTE dirty flag (00h = not dirty) 1Fh BYTE unused Format of reserved field for DOS 1.10-1.25: Offset Size Description 18h BYTE bit 7: set if logical device bit 6: not dirty bits 5-0: disk number or logical device ID 19h WORD starting cluster number on disk 1Bh WORD current absolute cluster number on disk 1Dh WORD current relative cluster number within file 1Fh BYTE unused Format of reserved field for DOS 2.x: Offset Size Description 18h BYTE bit 7: set if logical device bit 6: set if open??? bits 5-0: ??? 19h WORD starting cluster number on disk 1Bh WORD ??? 1Dh BYTE ??? 1Eh BYTE ??? 1Fh BYTE ??? Format of reserved field for DOS 3.x: Offset Size Description 18h BYTE number of system file table entry for file 19h BYTE attributes bits 7,6: 00 = SHARE.EXE not loaded, disk file 01 = SHARE.EXE not loaded, character device 10 = SHARE.EXE loaded, remote file 11 = SHARE.EXE loaded, local file bits 5-0: low six bits of device attribute word ---SHARE.EXE loaded, local file (DOS 3.x and 5.0)--- 1Ah WORD starting cluster of file on disk 1Ch WORD (DOS 3.x) offset within SHARE of sharing record (see AH=52h) (DOS 5.0) unique sequence number of sharing record 1Eh BYTE file attribute 1Fh BYTE ??? ---SHARE.EXE loaded, remote file--- 1Ah WORD number of sector containing directory entry 1Ch WORD relative cluster within file of last cluster accessed 1Eh BYTE absolute cluster number of last cluster accessed 1Fh BYTE ??? ---SHARE.EXE not loaded--- 1Ah BYTE (low byte of device attribute word AND 0Ch) OR open mode 1Bh WORD starting cluster of file 1Dh WORD number of sector containing directory entry 1Fh BYTE number of directory entry within sector Note: if FCB opened on character device, DWORD at 1Ah is set to the address of the device driver header, then the BYTE at 1Ah is overwritten. --------D-2110------------------------------- INT 21 - DOS 1+ - CLOSE FILE USING FCB AH = 10h DS:DX -> File Control Block (see AH=0Fh) Return: AL = status 00h successful FFh failed Notes: a successful close forces all disk buffers used by the file to be written and the directory entry to be updated not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=0Fh,AH=16h,AH=3Eh --------D-2111------------------------------- INT 21 - DOS 1+ - FIND FIRST MATCHING FILE USING FCB AH = 11h DS:DX -> unopened FCB (see AH=0Fh), may contain '?' wildcards Return: AL = status 00h successful [DTA] unopened FCB for first matching file FFh no matching filename, or bad FCB Notes: the type of the returned FCB depends on whether the input FCB was a normal or an extended FCB the data returned in the DTA is actually the drive number (or extended FCB header and drive number) followed by the file's directory entry (see below); this format happens to be compatible with an unopened FCB for extended FCBs with search attribute 08h, the volume label (if any) will be returned even if the current directory is not the root dir. DOS 3+ also allows the '*' wildcard the search FCB must not be modified if AH=12h will be used to continue searching; DOS 3.3 has set the following parts of the FCB: 0Ch BYTE ??? 0Dh WORD directory entry number of matching file 0Fh WORD cluster number of current directory 11h 4 BYTEs ??? 15h BYTE drive number (1=A:) SeeAlso: AH=12h,AH=1Ah,AH=4Eh,INT 2F/AX=111Bh Format of directory entry: Offset Size Description 00h 8 BYTEs blank-padded filename 08h 3 BYTEs blank-padded file extension 0Bh BYTE attributes 0Ch 10 BYTEs reserved 16h WORD time of creation or last update (see AX=5700h) 18h WORD date of creation or last update (see AX=5700h) 1Ah WORD starting cluster number 1Ch DWORD file size --------D-2112------------------------------- INT 21 - DOS 1+ - FIND NEXT MATCHING FILE USING FCB AH = 12h DS:DX -> unopened FCB (see AH=0Fh) Return: AL = status 00h successful [DTA] = unopened FCB FFh no more matching filenames Note: (see AH=11h) assumes that successful FindFirst executed on search FCB before call SeeAlso: AH=1Ah,AH=4Fh,INT 2F/AX=111Ch --------D-2113------------------------------- INT 21 - DOS 1+ - DELETE FILE USING FCB AH = 13h DS:DX -> unopened FCB (see AH=0Fh), filename filled with template for deletion ('?' wildcards allowed) Return: AL = status 00h one or more files successfully deleted FFh no matching files or all were read-only or locked Notes: DOS 1.25+ deletes everything in the current directory (including subdirectories) and sets the first byte of the name to 00h (entry never used) instead of E5h if called on an extended FCB with filename '???????????' and bits 0-4 of the attribute set (bits 1 and 2 for DOS 1.x). This may have originally been an optimization to minimize directory searching after a mass deletion (DOS 1.25+ stop the directory search upon encountering a never-used entry), but can corrupt the filesystem under DOS 2+ because subdirectories are removed without deleting the files they contain. currently-open files should not be deleted MS-DOS allows deletion of read-only files with an extended FCB, whereas Novell NetWare does not SeeAlso: AH=41h,INT 2F/AX=1113h --------D-2114------------------------------- INT 21 - DOS 1+ - SEQUENTIAL READ FROM FCB FILE AH = 14h DS:DX -> opened FCB (see AH=0Fh) Return: AL = status 00h successful 01h end of file (no data) 02h segment wrap in DTA 03h end of file, partial record read [DTA] = record read from file Notes: reads a record of the size specified in the FCB beginning at the current file position, then updates the current block and current record fields in the FCB if a partial record was read, it is zero-padded to the full size not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=0Fh,AH=15h,AH=1Ah,AH=3Fh,INT 2F/AX=1108h --------D-2115------------------------------- INT 21 - DOS 1+ - SEQUENTIAL WRITE TO FCB FILE AH = 15h DS:DX -> opened FCB (see AH=0Fh) [DTA] = record to write Return: AL = status 00h successful 01h disk full 02h segment wrap in DTA Notes: writes a record of the size specified in the FCB beginning at the current file position, then updates the current block and current record fields in the FCB if less than a full sector is written, the data is placed in a DOS buffer to be written out at a later time not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=0Fh,AH=14h,AH=1Ah,AH=40h,INT 2F/AX=1109h --------D-2116------------------------------- INT 21 - DOS 1+ - CREATE OR TRUNCATE FILE USING FCB AH = 16h DS:DX -> unopened FCB (see AH=0Fh), wildcards not allowed Return: AL = status 00h successful FFh directory full or file exists and is read-only or locked Notes: if file already exists, it is truncated to zero length if an extended FCB is used, the file is given the attribute in the FCB; this is how to create a volume label in the disk's root dir not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=0Fh,AH=10h,AH=3Ch --------D-2117------------------------------- INT 21 - DOS 1+ - RENAME FILE USING FCB AH = 17h DS:DX -> modified FCB (see also AH=0Fh) the old filename ('?' wildcards OK) is in the standard location while the new filename ('?' wildcards OK) is stored in the 11 bytes beginning at offset 11h Return: AL = status 00h successfully renamed FFh no matching files,file is read-only, or new name already exists Note: subdirectories may be renamed using an extended FCB with the appropriate attribute, as may volume labels SeeAlso: AH=0Fh,AH=13h,AH=56h,INT 2F/AX=1111h --------D-2118------------------------------- INT 21 - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY AH = 18h Return: AL = 00h Note: corresponds to the CP/M BDOS function "get bit map of logged drives", which is meaningless under MS-DOS SeeAlso: AH=1Dh,AH=1Eh,AH=20h,AX=4459h --------D-2119------------------------------- INT 21 - DOS 1+ - GET CURRENT DEFAULT DRIVE AH = 19h Return: AL = drive (00h = A:, 01h = B:, etc) Note: Novell NetWare uses the fact that DOS 2.x COMMAND.COM issues this call from a particular location every time it starts a command to determine when to issue an automatic EOJ SeeAlso: AH=0Eh,AH=47h,AH=BBh --------D-211A------------------------------- INT 21 - DOS 1+ - SET DISK TRANSFER AREA ADDRESS AH = 1Ah DS:DX -> Disk Transfer Area (DTA) Notes: the DTA is set to PSP:0080h when a program is started under the FlashTek X-32 DOS extender, the pointer is in DS:EDX SeeAlso: AH=11h,AH=12h,AH=2Fh,AH=4Eh,AH=4Fh --------D-211B------------------------------- INT 21 - DOS 1+ - GET ALLOCATION INFORMATION FOR DEFAULT DRIVE AH = 1Bh Return: AL = sectors per cluster (allocation unit) CX = bytes per sector DX = total number of clusters DS:BX -> media ID byte (see below) Note: under DOS 1.x, DS:BX points at an actual copy of the FAT; later versions return a pointer to a copy of the FAT's ID byte SeeAlso: AH=1Ch,AH=36h Values for media ID byte: FFh floppy, double-sided, 8 sectors per track (320K) FEh floppy, single-sided, 8 sectors per track (160K) FDh floppy, double-sided, 9 sectors per track (360K) FCh floppy, single-sided, 9 sectors per track (180K) F9h floppy, double-sided, 15 sectors per track (1.2M) F8h hard disk F0h other --------D-211C------------------------------- INT 21 - DOS 1+ - GET ALLOCATION INFORMATION FOR SPECIFIC DRIVE AH = 1Ch DL = drive (00h = default, 01h = A:, etc) Return: AL = sectors per cluster (allocation unit) CX = bytes per sector DX = total number of clusters DS:BX -> media ID byte (see AH=1Bh) Note: under DOS 1.x, DS:BX points at an actual copy of the FAT; later versions return a pointer to a copy of the FAT's ID byte SeeAlso: AH=1Bh,AH=36h --------D-211D------------------------------- INT 21 - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY AH = 1Dh Return: AL = 00h Note: corresponds to the CP/M BDOS function "get bit map of read-only drives", which is meaningless under MS-DOS SeeAlso: AH=18h,AH=1Eh,AH=20h,AX=4459h --------D-211E------------------------------- INT 21 - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY AH = 1Eh Return: AL = 00h Note: corresponds to the CP/M BDOS function "set file attributes" which was meaningless under MS-DOS 1.x SeeAlso: AH=18h,AH=1Dh,AH=20h --------D-211F------------------------------- INT 21 - DOS 1+ - GET DRIVE PARAMETER BLOCK FOR DEFAULT DRIVE AH = 1Fh Return: AL = status 00h successful DS:BX -> Drive Parameter Block (DPB) (see below for DOS 1.x, AH=32h for DOS 2+) FFh invalid drive Note: this call was undocumented prior to the release of DOS 5.0; however, only the DOS 4+ version of the DPB has been documented SeeAlso: AH=32h Format of DOS 1.1 and MS-DOS 1.25 drive parameter block: Offset Size Description 00h BYTE sequential device ID 01h BYTE logical drive number (0=A:) 02h WORD bytes per sector 04h BYTE highest sector number within a cluster 05h BYTE shift count to convert clusters into sectors 06h WORD starting sector number of first FAT 08h BYTE number of copies of FAT 09h WORD number of directory entries 0Bh WORD number of first data sector 0Dh WORD highest cluster number (number of data clusters + 1) 0Fh BYTE sectors per FAT 10h WORD starting sector of directory 12h WORD address of allocation table Note: the DOS 1.0 table is the same except that the first and last fields are missing; see INT 21/AH=32h for the DOS 2+ version --------D-2120------------------------------- INT 21 - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY AH = 20h Return: AL = 00h Note: corresponds to the CP/M BDOS function "get/set default user (sublibrary) number", which is meaningless under MS-DOS SeeAlso: AH=18h,AH=1Dh,AH=1Eh,AX=4459h --------D-2121------------------------------- INT 21 - DOS 1+ - READ RANDOM RECORD FROM FCB FILE AH = 21h DS:DX -> opened FCB (see AH=0Fh) Return: AL = status 00h successful 01h end of file, no data read 02h segment wrap in DTA, no data read 03h end of file, partial record read [DTA] = record read from file Notes: the record is read from the current file position as specified by the random record and record size fields of the FCB the file position is not updated after reading the record if a partial record is read, it is zero-padded to the full size not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=14h,AH=22h,AH=27h,AH=3Fh --------D-2122------------------------------- INT 21 - DOS 1+ - WRITE RANDOM RECORD TO FCB FILE AH = 22h DS:DX -> opened FCB (see AH=0Fh) [DTA] = record to write Return: AL = status 00h successful 01h disk full 02h segment wrap in DTA Notes: the record is written to the current file position as specified by the random record and record size fields of the FCB the file position is not updated after writing the record if the record is located beyond the end of the file, the file is extended but the intervening data remains uninitialized if the record only partially fills a disk sector, it is copied to a DOS disk buffer to be written out to disk at a later time not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=15h,AH=21h,AH=28h,AH=40h --------D-2123------------------------------- INT 21 - DOS 1+ - GET FILE SIZE FOR FCB AH = 23h DS:DX -> unopened FCB (see AH=0Fh), wildcards not allowed Return: AL = status 00h successful (matching file found) FCB random record field filled with size in records, rounded up to next full record FFh failed (no matching file found) Note: not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=42h --------D-2124------------------------------- INT 21 - DOS 1+ - SET RANDOM RECORD NUMBER FOR FCB AH = 24h DS:DX -> opened FCB (see AH=0Fh) Notes: computes the random record number corresponding to the current record number and record size, then stores the result in the FCB normally used when switching from sequential to random access not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=21h,AH=27h,AH=42h --------D-2125------------------------------- INT 21 - DOS 1+ - SET INTERRUPT VECTOR AH = 25h AL = interrupt number DS:DX -> new interrupt handler Notes: this function is preferred over direct modification of the interrupt vector table some DOS extenders place an API on this function, as it is not directly meaningful in protected mode under DR-DOS 5.0, this function does not use any of the DOS-internal stacks and may thus be called at any time Novell NetWare (except the new DOS Requester) monitors the offset of any INT 24 set, and if equal to the value at startup, substitutes its own handler to allow handling of network errors; this introduces the potential bug that any program whose INT 24 handler offset happens to be the same as COMMAND.COM's will not have its INT 24 handler installed SeeAlso: AX=2501h,AH=35h --------E-212501----------------------------- INT 21 P - Phar Lap 386/DOS-Extender - RESET DOS EXTENDER DATA STRUCTURES AX = 2501h SS = application's original SS or DS (FlashTek X-32VM) Return: CF clear if successful CF set on error caller is operating on X-32 stack (FlashTek X-32VM) Notes: Phar Lap uses INT 21/AH=25h as the entry point for all 386/DOS-Extender system calls. Only available when directly using 386/DOS-Extender or a compatible DOS extender, or when using a product that was created using 386-DOS/Extender or a compatible this function is also supported by FlashTek X-32VM SeeAlso: AH=30h"Phar Lap" --------E-212502----------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET PROTECTED-MODE INTERRUPT VECTOR AX = 2502h CL = interrupt number Return: CF clear ES:EBX = CS:EIP of protected-mode interrupt handler Note: this function is also supported by FlashTek X-32VM SeeAlso: AX=2503h,AX=2504h,INT 31/AX=0204h --------E-212503----------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET REAL-MODE INTERRUPT VECTOR AX = 2503h CL = interrupt number Return: CF clear EBX = CS:IP of real-mode interrupt handler Note: this function is also supported by FlashTek X-32VM SeeAlso: AX=2502h,AX=2504h,AH=35h,INT 31/AX=0200h --------E-212504----------------------------- INT 21 - Phar Lap 386/DOS-Extender - SET PROTECTED-MODE INTERRUPT VECTOR AX = 2504h CL = interrupt number DS:EDX = CS:EIP of protected-mode interrupt handler Return: CF clear Note: this function is also supported by FlashTek X-32VM SeeAlso: AX=2502h,AX=2505h,INT 31/AX=0205h --------E-212505----------------------------- INT 21 - Phar Lap 386/DOS-Extender - SET REAL-MODE INTERRUPT VECTOR AX = 2505h CL = interrupt number EBX = CS:IP of real-mode interrupt handler Return: CF clear Note: this function is also supported by FlashTek X-32VM SeeAlso: AX=2503h,AX=2504h,INT 31/AX=0201h --------E-212506----------------------------- INT 21 - Phar Lap 386/DOS-Extender - SET INT TO ALWAYS GAIN CONTRL IN PROT MODE AX = 2506h CL = interrupt number DS:EDX = CS:EIP of protected-mode interrupt handler Return: CF clear Notes: this function modifies both the real-mode low-memory interrupt vector table and the protected-mode Interrupt Descriptor Table (IDT) interrupts occurring in real mode are resignaled in protected mode this function is also supported by FlashTek X-32VM --------E-212507----------------------------- INT 21 - Phar Lap 386/DOS-Extender - SET REAL- & PROTECTED-MODE INT VECTORS AX = 2507h CL = interrupt numbern DS:EDX = CS:EIP of protected-mode interrupt handler EBX = CS:IP of real-mode interrupt handler Return: CF clear Notes: interrupts are disabled until both vectors have been modified this function is also supported by FlashTek X-32VM SeeAlso: AX=2504h,AX=2505h --------E-212508----------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET SEGMENT LINEAR BASE ADDRESS AX = 2508h BX = segment selector Return: CF clear if successful ECX = linear base address of segment CF set if invalid segment selector Note: this function is also supported by FlashTek X-32VM SeeAlso: AX=2509h --------E-212509----------------------------- INT 21 - Phar Lap 386/DOS-Extender - CONVERT LINEAR TO PHYSICAL ADDRESS AX = 2509h EBX = linear address to convert Return: CF clear if successful ECX = physical address (carry flag clear) CF set if linear address not mapped in page tables SeeAlso: AX=2508h --------E-212509----------------------------- INT 21 - FlashTek X-32VM - GET SYSTEM SEGMENTS AND SELECTORS AX = 2509h Return: CF clear EAX high word = default DS AX = alias for 16-bit data segment BX = real mode code segment EDX high word = selector covering full 4GB address space DX = default SS ESI high word = PSP selector SI = environment selector --------E-21250A----------------------------- INT 21 - Phar Lap 386/DOS-Extender - MAP PHYSICAL MEMORY AT END OF SEGMENT AX = 250Ah ES = segment selector in the Local Descriptor Table (LDT) of segment to modify EBX = physical base address of memory to map (multiple of 4K) ECX = number of physical 4K pages to map Return: CF clear if successful EAX = 32-bit offset in segment of mapped memory CF set on error EAX = error code 08h insufficient memory to create page tables 09h invalid segment selector SeeAlso: INT 31/AX=0800h --------E-21250C----------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET HARDWARE INTERRUPT VECTORS AX = 250Ch Return: CF clear AL = base interrupt vector for IRQ0-IRQ7 AH = base interrupt vector for IRQ8-IRQ15 BL = interrupt vector for BIOS print screen function (Phar Lap only) Note: this function is also supported by FlashTek X-32VM SeeAlso: INT 31/AX=0400h,INT 67/AX=DE0Ah --------E-21250D----------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET REAL-MODE LINK INFORMATION AX = 250Dh Return: CF clear EAX = CS:IP of real-mode callback procedure that will call through from real mode to a protected-mode routine EBX = 32-bit real-mode address of intermode call data buffer ECX = size in bytes of intermode call data buffer ES:EDX = protected-mode address of intermode call data buffer Notes: this function is also supported by FlashTek X-32VM X-32VM guarantees the intermode buffer to be at least 4 KB SeeAlso: AX=250Eh Call real-mode callback with: STACK: DWORD offset to protected-mode code WORD placeholder for protected-mode CS DWORD pointer to selector structure (see below) or 0000h:0000h for defaults var parameters for protected-mode procedure Return: via FAR return Format of selector structure: Offset Size Description 00h WORD protected-mode GS selector 02h WORD protected-mode FS selector 04h WORD protected-mode ES selector 06h WORD protected-mode DS selector --------E-21250E----------------------------- INT 21 - Phar Lap 386/DOS-Extender - CALL REAL-MODE PROCEDURE AX = 250Eh EBX = CS:IP of real-mode procedure to call ECX = number of two-byte words to copy from protected-mode stack to real-mode stack Return: CF clear if successful all segment registers unchanged all general registers contain values set by real-mode procedure all other flags set as they were left by real-mode procedure stack unchanged CF set on error EAX = error code 01h not enough real-mode stack space Note: this function is also supported by FlashTek X-32VM; under X-32VM, the call will fail if ECX > 0000003Fh SeeAlso: AX=250Dh,AX=2510h,AH=E1h"OS/286",INT 31/AX=0301h --------E-21250F----------------------------- INT 21 - Phar Lap 386/DOS-Extender - CONVERT PROTECTED-MODE ADDRESS TO MS-DOS AX = 250Fh ES:EBX = 48-bit protected-mode address to convert Return: CF clear if successful (address < 1MB) ECX = 32-bit real-mode MS-DOS address CF set on error (address >= 1MB) ECX = linear address Note: this function is also supported by FlashTek X-32VM SeeAlso: AX=2510h --------E-212510----------------------------- INT 21 - Phar Lap 386/DOS-Extender - CALL REAL-MODE PROCEDURE, REGISTERS AX = 2510h EBX = CS:IP of real-mode procedure to call ECX = number of two-byte words to copy to protected-mode stack to real-mode stack DS:EDX -> pointer to parameter block (see below) Return: CF clear if successful all segment registers unchanged, EDX unchanged all other general registers contain values set by real-mode proc all other flags are set as they were left by real-mode procedure real-mode register values are returned in the parameter block CF set on error EAX = error code 01h not enough real-mode stack space Note: unlike most of the preceding 25xxh functions, this one is not supported by FlashTek X-32VM SeeAlso: AX=250Eh,AX=250Fh Format of parameter block: Offset Size Description 00h WORD real-mode DS value 02h WORD real-mode ES value 04h WORD real-mode FS value 06h WORD real-mode GS value 08h DWORD real-mode EAX value 0Ch DWORD real-mode EBX value 10h DWORD real-mode ECX value 14h DWORD real-mode EDX value --------E-212511----------------------------- INT 21 - Phar Lap 386/DOS-Extender - ISSUE REAL-MODE INTERRUPT AX = 2511h DS:EDX -> parameter block (see below) Return: all segment registers unchanged EDX unchanged all other registers contain values set by the real-mode int handler the flags are set as they were left by the real-mode interrupt handler real-mode register values are returned in the parameter block Note: this function is also supported by FlashTek X-32VM SeeAlso: AX=2503h,AX=2505h,AX=250Eh,AH=E3h"OS/286",INT 31/AX=0300h Format of parameter block: Offset Size Description 00h WORD interrupt number 02h WORD real-mode DS value 04h WORD real-mode ES value 06h WORD real-mode FS value 08h WORD real-mode GS value 0Ah DWORD real-mode EAX value 0Eh DWORD real-mode EDX value Note: all other real-mode values set from protected-mode registers --------E-212512----------------------------- INT 21 - Phar Lap 386/DOS-Extender - LOAD PROGRAM FOR DEBUGGING AX = 2512h DS:EDX -> pointer to ASCIIZ program name ES:EBX -> pointer to parameter block (see below) ECX = size in bytes of LDT buffer Return: CF clear if successful EAX = number of segment descriptors in LDT CF set on error EAX = error code 02h file not found or path invalid 05h access denied 08h insufficient memory 0Ah environment invalid 0Bh invalid file format 80h LDT too small Format of parameter block: Offset Size Description Input: 00h DWORD 32-bit offset of environment string 04h WORD segment of environment string 06h DWORD 32-bit offset of command-tail string 0Ah WORD segment of command-tail string 0Ch DWORD 32-bit offset of LDT buffer (size in ECX) 10h WORD segment of LDT buffer Output: 12h WORD real-mode paragraph address of PSP (see also AH=26h) 14h WORD real/protected mode flag 0000h real mode 0001h protected mode 16h DWORD initial EIP value 1Ah WORD initial CS value 1Ch DWORD initial ESP value 20h WORD initial SS value 22h WORD initial DS value 24h WORD initial ES value 26h WORD initial FS value 28h WORD initial GS value --------E-212513----------------------------- INT 21 - Phar Lap 386/DOS-Extender - ALIAS SEGMENT DESCRIPTOR AX = 2513h BX = segment selector of descriptor in GDT or LDT CL = access-rights byte for alias descriptor CH = use-type bit (USE16 or USE32) for alias descriptor Return: CF clear if successful AX = segment selector for created alias CF set on error EAX = error code 08h insufficient memory (can't grow LDT) 09h invalid segment selector in BX --------E-212514----------------------------- INT 21 - Phar Lap 386/DOS-Extender - CHANGE SEGMENT ATTRIBUTES AX = 2514h BX = segment selector of descriptor in GDT or LDT CL = new access-rights byte CH = new use-type bit (USE16 or USE32) Return: CF clear if successful CF set on error EAX = error code 09h invalid selector in BX SeeAlso: AX=2515h,INT 31/AX=0009h --------E-212515----------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET SEGMENT ATTRIBUTES AX = 2515h BX = segment selector of descriptor in GDT or LDT Return: CF clear if successful CL = access-rights byte for segment CH = use-type bit (USE16 or USE32) ECX<16-31> destroyed CF set on error EAX = error code 09h invalid segment selector in BX SeeAlso: AX=2514h --------E-212516----------------------------- INT 21 - Phar Lap 386/DOS-Extender - FREE ALL MEMORY OWNED BY LDT AX = 2516h ??? Return: ??? --------E-212517----------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET INFO ON DOS DATA BUFFER AX = 2517h ??? Return: ??? --------E-212518----------------------------- INT 21 - Phar Lap 386/DOS-Extender - SPECIFY HANDLER FOR MOVED SEGMENTS AX = 2518h ??? Return: ??? --------E-212519----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - GET ADDITIONAL MEMORY ERROR INFO AX = 2519h Return: CF clear EAX = error code 0000h no error 0001h out of physical memory 0002h out of swap space (unable to grow swap file) 0003h out of LDT entries and unable to grow LDT 0004h unable to change extended memory allocation mark FFFFFFFFh paging disabled Note: VMM is the Virtual Memory Manager option --------E-21251A----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - LOCK PAGES IN MEMORY AX = 251Ah EDX = number of 4k pages to lock if BL = 00h ECX = linear address of first page to lock if BL = 01h ES:ECX -> pointer to first page to lock Return: CF clear if successful CF set on error EAX = error code 08h insufficient memory 09h invalid address range SeeAlso: AX=251Bh,AX=EB06h,INT 31/AX=0600h --------E-21251B----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - UNLOCK PAGES AX = 251Bh EDX = number of pages to unlock if BL = 00h ECX = linear address of first page to unlock if BL = 01h ES:ECX -> pointer to first page to unlock Return: CF clear if successful CF set on error EAX = error code 09h invalid address range SeeAlso: AX=251Ah,AX=EB07h,INT 31/AX=0601h --------E-21251D----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - READ PAGE-TABLE ENTRY AX = 251Dh ??? Return: ??? SeeAlso: AX=251Eh,AX=EB00h,INT 31/AX=0506h --------E-21251E----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - WRITE PAGE-TABLE ENTRY AX = 251Eh ??? Return: ??? SeeAlso: AX=251Dh,INT 31/AX=0507h --------E-21251F----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - EXHANGE TWO PAGE-TABLE ENTRIES AX = 251Fh ??? Return: ??? SeeAlso: AX=251Dh,AX=251Eh --------E-212520----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - GET MEMORY STATISTICS AX = 2520h DS:EDX -> pointer to buffer at least 100 bytes in size (see below) BL = 0 (don't reset VM stats), 1 (reset VM stats) Return: carry flag clear Format of VM stats buffer: Offset Size Description 00h DWORD VM status 0001h VM subsystem is present 0000h VM not present 04h DWORD "nconvpg" number of conventional memory pages available 08h DWORD "nbimpg" number of Compaq built-in memory pages available 0Ch DWORD "nextpg" total number of extended memory pages 10h DWORD "extlim" extender memory pages limit 14h DWORD "aphyspg" number of physical memory pages allocated to appl 18h DWORD "alockpg" number of locked pages owned by application 1Ch DWORD "sysphyspg" number physical memory pages allocated to system 20h DWORD "nfreepg" number of free physical pages; approx if EMS VCPI 24h DWORD linear address of beginning of application address space 28h DWORD linear address of end of application address space 2Ch DWORD number of seconds since last time VM stats were reset 30h DWORD number of page faults since last time 34h DWORD number of pages written to swap file since last time 38h DWORD number of reclaimed pages (page faults on swapped pages) 3Ch DWORD number of virtual pages allocated to the application 40h DWORD size in pages of swap file 44h DWORD number of system pages allocated with EMS calls 48h DWORD minimum number of conventional memory pages 4Ch DWORD maximum size in bytes to which swap file can be increased 50h DWORD "vmflags" bit 0 = 1 if page fault in progress 54h 16 BYTEs reserved for future expansion (set to zero) --------E-212521----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - LIMIT PROGRAM'S EXTENDED MEMORY USAGE AX = 2521h EBX = max 4k pages of physical extended memory which program may use Return: CF clear if successful EBX = maximum limit in pages ECX = minimum limit in pages CF set on error EAX = error code 08h insufficient memory or -nopage switch used SeeAlso: AX=2522h --------E-212522----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - SPECIFY ALTERNATE PAGE-FAULT HANDLER AX = 2522h ??? Return: ??? SeeAlso: AX=2523h --------E-212523----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - SPECIFY OUT-OF-SWAP-SPACE HANDLER AX = 2523h ??? Return: ??? SeeAlso: AX=2522h --------E-212524----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - INSTALL PAGE-REPLACEMENT HANDLERS AX = 2524h ??? Return: ??? --------E-212525----------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - LIMIT PROGRAM'S CONVENTIONAL MEM USAGE AX = 2525h EBX = limit in 4k pages of physical conventional memory which program may use Return: CF clear if successful EBX = maximum limit in pages ECX = minimum limit in pages CF set on error EAX = error code 08h insufficient memory or -nopage switch used SeeAlso: AX=2521h --------E-212526----------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET CONFIGURATION INFORMATION AX = 2526h ??? Return: ??? --------E-21252B----------------------------- INT 21 - FlashTek X-32VM - VIRTUAL MEMORY MANAGEMENT - PAGE LOCKING AX = 252Bh BH = function 05h lock pages 06h unlock pages BL = address type 00h linear address ECX = linear start address of memory region 01h segmented address ES:ECX -> start of memory region EDX = size of memory region in bytes Return: CF clear if successful CF set on error Note: if X-32 is not using virtual memory, this function always succeeds --------E-212532----------------------------- INT 21 - FlashTek X-32VM - GET EXCEPTION HANDLER VECTOR AX = 2532h CL = exception number (00h-0Fh) Return: CF clear if successful ES:EBX = CS:EIP of current exception handler CF set on error (CL > 0Fh) SeeAlso: AX=2533h --------E-212533----------------------------- INT 21 - FlashTek X-32VM - SET EXCEPTION HANDLER VECTOR AX = 2533h CL = exception number (00h-0Fh) DS:EDX = CS:EIP of new exception handler Return: CF clear if successful CF set on error (CL > 0Fh) SeeAlso: AX=2532h --------E-2125C0----------------------------- INT 21 - Phar Lap 386/DOS-Extender - ALLOCATE MS-DOS MEMORY BLOCK AX = 25C0h BX = number of 16-byte paragraphs of MS-DOS memory requested Return: CF clear if successful AX = real-mode paragraph address of memory CF set on error AX = error code 07h MS-DOS memory control blocks destroyed 08h insufficient memory BX = size in paragraphs of largest available memory block SeeAlso: AX=25C1h,AX=25C2h --------E-2125C1----------------------------- INT 21 - Phar Lap 386/DOS-Extender - RELEASE MS-DOS MEMORY BLOCK AX = 25C1h CX = real-mode paragraph address of memory block to free Return: CF clear if successful EAX destroyed CF set on error AX = error code 07h MS-DOS memory control blocks destroyed 09h invalid memory block address in CX SeeAlso: AX=25C0h,AX=25C2h --------E-2125C2----------------------------- INT 21 - Phar Lap 386/DOS-Extender - MODIFY MS-DOS MEMORY BLOCK AX = 25C2h BX = new requested block size in paragraphs CX = real-mode paragraph address of memory block to modify Return: CF clear if successful EAX destroyed CF set on error AX = error code 07h MS-DOS memory control blocks destroyed 08h insufficient memory 09h invalid memory block address in CX BX = size in paragraphs of largest available memory block SeeAlso: AX=25C0h,AX=25C1h --------E-2125C3----------------------------- INT 21 - Phar Lap 386/DOS-Extender - EXECUTE PROGRAM AX = 25C3h ES:EBX -> pointer to parameter block (see below) DS:EDX -> pointer to ASCIIZ program filename Return: CF clear if successful all registers unchanged CF set on error EAX = error code 01h function code in AL is invalid ??? 02h file not found or path invalid 05h access denied 08h insufficient memory to load program 0Ah environment invalid 0Bh invalid file format Format of parameter block: Offset Size Description 00h DWORD 32-bit offset of environment string 04h WORD segment selector of environment string 06h DWORD 32-bit offset of command-tail string 0Ah WORD segment selector of command-tail string --------D-2126------------------------------- INT 21 - DOS 1+ - CREATE NEW PROGRAM SEGMENT PREFIX AH = 26h DX = segment at which to create PSP (see below) Notes: new PSP is updated with memory size information; INTs 22h, 23h, 24h taken from interrupt vector table (DOS 2+) DOS assumes that the caller's CS is the segment of the PSP to copy SeeAlso: AH=4Bh,AH=50h,AH=51h,AH=55h,AH=62h,AH=67h Format of PSP: Offset Size Description 00h 2 BYTEs INT 20 instruction for CP/M CALL 0 program termination the CDh 20h here is often used as a signature for a valid PSP 02h WORD segment of first byte beyond memory allocated to program 04h BYTE unused filler 05h BYTE CP/M CALL 5 service request (FAR JMP to 000C0h) BUG: (DOS 2+) PSPs created by INT 21/AH=4Bh point at 000BEh 06h WORD CP/M compatibility--size of first segment for .COM files 08h 2 BYTEs remainder of FAR JMP at 05h 0Ah DWORD stored INT 22 termination address 0Eh DWORD stored INT 23 control-Break handler address 12h DWORD DOS 1.1+ stored INT 24 critical error handler address 16h WORD segment of parent PSP 18h 20 BYTEs DOS 2+ Job File Table, one byte per file handle, FFh = closed 2Ch WORD DOS 2+ segment of environment for process 2Eh DWORD DOS 2+ process's SS:SP on entry to last INT 21 call 32h WORD DOS 3+ number of entries in JFT (default 20) 34h DWORD DOS 3+ pointer to JFT (default PSP:0018h) 38h DWORD DOS 3+ pointer to previous PSP (default FFFFFFFFh in 3.x) used by SHARE in DOS 3.3 3Ch 4 BYTEs unused by DOS versions <= 6.00 reportedly used by Novell NetWare shell 3.x 40h 2 BYTEs DOS 5+ version to return on INT 21/AH=30h 42h WORD (MSWin3) selector of next PSP (PDB) in linked list Windows keeps a linked list of Windows programs only 44h 4 BYTEs unused by DOS versions <= 6.00 48h BYTE (MSWindows3) bit 0 set if non-Windows application (WINOLDAP) 49h 7 BYTEs unused by DOS versions <= 6.00 50h 3 BYTEs DOS 2+ service request (INT 21/RETF instructions) 53h 9 BYTEs unused in DOS versions <= 6.00 5Ch 16 BYTEs first default FCB, filled in from first commandline argument overwrites second FCB if opened 6Ch 16 BYTEs second default FCB, filled in from second commandline argument overwrites beginning of commandline if opened 7Ch 4 BYTEs unused 80h 128 BYTEs commandline / default DTA command tail is BYTE for length of tail, N BYTEs for the tail, followed by a BYTE containing 0Dh Notes: in DOS v3+, the limit on simultaneously open files may be increased by allocating memory for a new open file table, filling it with FFh, copying the first 20 bytes from the default table, and adjusting the pointer and count at 34h and 32h. However, DOS will only copy the first 20 file handles into a child PSP (including the one created on EXEC). network redirectors based on the original MS-Net implementation use values of 80h-FEh in the open file table to indicate remote files; Novell NetWare reportedly also uses values of 80h-FEh MS-DOS 5.00 incorrectly fills the FCB fields when loading a program high; the first FCB is empty and the second contains the first parameter some DOS extenders place protected-mode values in various PSP fields such as the "parent" field, which can confuse PSP walkers. Always check either for the CDh 20h signature or that the suspected PSP is at the beginning of a memory block which owns itself (the preceding paragraph should be a valid MCB with "owner" the same as the suspected PSP). Format of environment block: Offset Size Description 00h N BYTEs first environment variable, ASCIZ string of form "var=value" N BYTEs second environment variable, ASCIZ string ... N BYTEs last environment variable, ASCIZ string of form "var=value" BYTE 00h ---DOS 3+--- WORD number of strings following environment (normally 1) N BYTEs ASCIZ full pathname of program owning this environment other strings may follow --------D-2127------------------------------- INT 21 - DOS 1+ - RANDOM BLOCK READ FROM FCB FILE AH = 27h CX = number of records to read DS:DX -> opened FCB (see AH=0Fh) Return: AL = status 00h successful, all records read 01h end of file, no data read 02h segment wrap in DTA, no data read 03h end of file, partial read [DTA] = records read from file CX = number of records read (return AL = 00h or 03h) Notes: read begins at current file position as specified in FCB; the file position is updated after reading not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=21h,AH=28h,AH=3Fh --------D-2128------------------------------- INT 21 - DOS 1+ - RANDOM BLOCK WRITE TO FCB FILE AH = 28h CX = number of records to write DS:DX -> opened FCB (see AH=0Fh) [DTA] = records to write Return: AL = status 00h successful 01h disk full or file read-only 02h segment wrap in DTA CX = number of records written Notes: write begins at current file position as specified in FCB; the file position is updated after writing if CX = 0000h on entry, no data is written; instead the file size is adjusted to be the same as the file position specified by the random record and record size fields of the FCB if the data to be written is less than a disk sector, it is copied into a DOS disk buffer, to be written out to disk at a later time not supported by MS Windows 3.0 DOSX.EXE DOS extender SeeAlso: AH=22h,AH=27h,AH=40h,AH=59h --------D-2129------------------------------- INT 21 - DOS 1+ - PARSE FILENAME INTO FCB AH = 29h AL = parsing options (see below) DS:SI -> filename string (both '*' and '?' wildcards OK) ES:DI -> buffer for unopened FCB Return: AL = result code 00h successful parse, no wildcards encountered 01h successful parse, wildcards present FFh failed (invalid drive specifier) DS:SI -> first unparsed character ES:DI buffer filled with unopened FCB (see AH=0Fh) Notes: asterisks expanded to question marks in the FCB all processing stops when a filename terminator is encountered cannot be used with filespecs which include a path (DOS 2+) Novell NetWare monitors the result code since an 'invalid drive' may signal an attempt to reconnect a network drive; if there are no connections to the specified drive, NetWare attempts to build a connection and map the drive to the SYS:LOGIN directory SeeAlso: AH=0Fh,AH=16h,AH=26h Bitfields for parsing options: bit 0 skip leading separators bit 1 use existing drive number in FCB if no drive is specified, instead of setting field to zero bit 2 use existing filename in FCB if no base name is specified, instead of filling field with blanks bit 3 use existing extension in FCB if no extension is specified, instead of filling field with blanks bits 4-7 reserved (0) --------D-212A------------------------------- INT 21 - DOS 1+ - GET SYSTEM DATE AH = 2Ah Return: CX = year (1980-2099) DH = month DL = day ---DOS 1.10+--- AL = day of week (00h=Sunday) SeeAlso: AH=2Bh"DOS",AH=2Ch,AH=E7h,INT 1A/AH=04h,INT 2F/AX=120Dh --------D-212B------------------------------- INT 21 - DOS 1+ - SET SYSTEM DATE AH = 2Bh CX = year (1980-2099) DH = month DL = day Return: AL = status 00h successful FFh invalid date, system date unchanged Note: DOS 3.3+ also sets CMOS clock SeeAlso: AH=2Ah,AH=2Dh,INT 1A/AH=05h --------E-212B--CX4149----------------------- INT 21 - AI Architects - ??? - INSTALLATION CHECK AH = 2Bh CX = 4149h ('AI') DX = 413Fh ('A?') Return: AL <> FFh if installed Note: Borland's TKERNEL makes this call --------c-212B--CX4358----------------------- INT 21 - PC Tools v5.x PC-Cache - INSTALLATION CHECK AH = 2Bh CX = 4358h ('CX') Return: AL = FFh if PC-Cache not installed AL = 00h if installed CX = 6378h ('cx') BX = ??? DX = ??? SeeAlso: INT 16/AX=FFA5h/CX=1111h --------Q-212B--CX4445----------------------- INT 21 - DESQview - INSTALLATION CHECK AH = 2Bh CX = 4445h ('DE') DX = 5351h ('SQ') AL = subfunction (DV v2.00+) 01h get version Return: BX = version (BH = major, BL = minor) Note: early copies of v2.00 return 0002h 02h get shadow buffer info, and start shadowing Return: BH = rows in shadow buffer BL = columns in shadow buffer DX = segment of shadow buffer 04h get shadow buffer info Return: BH = rows in shadow buffer BL = columns in shadow buffer DX = segment of shadow buffer 05h stop shadowing Return: AL = FFh if DESQview not installed Notes: in DESQview v1.x, there were no subfunctions; this call only identified whether or not DESQview was loaded. DESQview v2.52 performs function 01h for all subfunction requests 0Ch and higher and appears to ignore all lower-numbered functions not listed here. DESQview versions 2.5x are part of DESQview/X v1.0x. BUG: subfunction 05h does not appear to work correctly in DESQview 2.52 SeeAlso: INT 10/AH=FEh,INT 10/AH=FFh,INT 15/AX=1024h,INT 15/AX=DE30h --------U-212B--CX454C----------------------- INT 21 - ELRES v1.1 - INSTALLATION CHECK AH = 2Bh CX = 454Ch ('EL') DX = 5253h ('RS') Return: ES:BX -> ELRES history structure (see below) DX = DABEh (signature, DAve BEnnett) Program: ELRES is an MS-DOS return code (errorlevel) recorder by David H. Bennett which stores recent errorlevel values, allows them to be retrieved for use in batch files, and can place them in an environment variable SeeAlso: AH=4Bh"ELRES",AH=4Dh Format of ELRES history structure: Offset Size Description 00h WORD number of return codes which can be stored by following buffer 02h WORD current position in buffer (treated as a ring) 04h N BYTEs ELRES buffer --------T-212B01CX5441----------------------- INT 21 - TAME v2.10+ - INSTALLATION CHECK AX = 2B01h CX = 5441h ('TA') DX = 4D45h ('ME') ---v2.60--- BH = ??? 00h skip ???, else do Return: AL = 02h if installed ES:DX -> data area in TAME-RES (see below) Program: TAME is a shareware program by David G. Thomas which gives up CPU time to other partitions under a multitasker when the current partition's program incessantly polls the keyboard or system time Format of TAME 2.10-2.20 data area: Offset Size Description 00h BYTE data structure minor version number (01h in TAME 2.20) 01h BYTE data structure major version number (07h in TAME 2.20) 02h DWORD number of task switches 06h DWORD number of keyboard polls 0Ah DWORD number of time polls 0Eh DWORD number of times DESQview told program runs only in foreground 12h DWORD original INT 10h 16h DWORD original INT 14h 1Ah DWORD original INT 15h 1Eh DWORD original INT 16h 22h DWORD original INT 17h 26h DWORD original INT 21h 2Ah DWORD original INT 28h 2Eh WORD offset of TAME INT 10h handler 30h WORD offset of TAME INT 14h handler 32h WORD offset of TAME INT 15h handler 34h WORD offset of TAME INT 16h handler 36h WORD offset of TAME INT 17h handler 38h WORD offset of TAME INT 21h handler 3Ah WORD offset of TAME INT 28h handler 3Ch WORD X in /max:X,Y or /freq:X,Y 3Eh WORD Y in /max:X,Y or /freq:X,Y 40h WORD number of polls remaining before next task switch 42h WORD /KEYIDLE value 44h BYTE interrupts already grabbed by TAME (see below) 45h BYTE flags for interrupts which may be acted on (same bits as above) 46h BYTE TAME enabled (01h) or disabled (00h) 47h BYTE /TIMEPOLL (01h) or /NOTIMEPOLL (00h) 48h BYTE /NOTIMER (01h) or /TIMER (00h) 49h BYTE window or task number for this task 4Ah BYTE multitasker type ??? 01h DESQview 02h DoubleDOS 03h TopView ??? 4Bh BYTE type of task switching selected bit 0: DESQview??? bit 1: DoubleDOS??? bit 2: TopView??? bit 3: KeySwitch bit 4: HLT instruction 4Ch BYTE ??? 4Dh BYTE flags bit 1: /FREQ instead of /MAX 4Eh BYTE /FG: value 4Fh BYTE task switches left until next FGONLY DESQview API call 50h BYTE ??? Bitfields for interrupts already grabbed by TAME: bit 0 INT 10h bit 1 INT 14h bit 2 INT 15h bit 3 INT 16h bit 4 INT 17h bit 5 INT 21h bit 6 INT 28h Format of TAME 2.30 data area: Offset Size Description 00h BYTE data structure minor version number (02h in TAME 2.30) 01h BYTE data structure major version number (0Ah in TAME 2.30) 02h DWORD number of task switches 06h DWORD number of keyboard polls 0Ah DWORD number of time polls 0Eh DWORD number of times DESQview told program runs only in foreground 12h DWORD time of last /CLEAR or TAME-RES load 16h DWORD time yielded 1Ah DWORD time spent polling 1Eh DWORD time spent waiting on key input with INT 16/AH=01h,11h 22h DWORD original INT 10h 26h DWORD original INT 14h 2Ah DWORD original INT 15h 2Eh DWORD original INT 16h 32h DWORD original INT 17h 36h DWORD original INT 21h 3Ah DWORD original INT 28h 3Eh WORD offset of TAME INT 10h handler 40h WORD offset of TAME INT 14h handler 42h WORD offset of TAME INT 15h handler 44h WORD offset of TAME INT 16h handler 46h WORD offset of TAME INT 17h handler 48h WORD offset of TAME INT 21h handler 4Ah WORD offset of TAME INT 28h handler 4Ch WORD X in /max:X,Y or /freq:X,Y 4Eh WORD Y in /max:X,Y or /freq:X,Y 50h WORD number of polls remaining before next task switch 52h WORD /KEYIDLE value 54h WORD /FG: value 56h WORD task switches left until next FGONLY DESQview API call 58h WORD multitasker version 5Ah WORD virtual screen segment 5Ch BYTE interrupts already grabbed by TAME (see above) 5Dh BYTE flags for interrupts which may be acted on (same bits as above) 5Eh BYTE window or task number for this task 5Fh BYTE multitasker type 01h DESQview 02h DoubleDOS 03h TopView 04h OmniView 05h VM/386 60h BYTE type of task switching selected (bit flags) bit 0: DESQview bit 1: DoubleDOS bit 2: TopView bit 3: OmniView bit 4: KeySwitch bit 5: HLT instruction 61h BYTE watch_DOS 62h BYTE bit flags bit 0: TAME enabled bit 1: /FREQ instead of /MAX (counts in 3Ch and 3Eh per tick) bit 2: /TIMEPOLL bit 3: /KEYPOLL bit 4: inhibit timer bit 5: enable status monitoring 63h BYTE old status 64h WORD signature DA34h Format of TAME 2.60 data area: Offset Size Description 00h BYTE data structure minor version number (02h in TAME 2.60) 01h BYTE data structure major version number (0Bh in TAME 2.60) 02h DWORD number of task switches 06h DWORD number of keyboard polls 0Ah DWORD number of time polls 0Eh DWORD number of times DESQview told program runs only in foreground 12h DWORD time of last /CLEAR or TAME-RES load 16h DWORD time yielded 1Ah DWORD time spent polling 1Eh DWORD time spent waiting on key input with INT 16/AH=01h,11h 22h 4 BYTEs ??? 26h DWORD original INT 10h 2Ah DWORD original INT 14h 2Eh DWORD original INT 15h 32h DWORD original INT 16h 36h DWORD original INT 17h 3Ah DWORD original INT 21h 3Eh DWORD original INT 28h 42h WORD offset of TAME INT 10h handler 44h WORD offset of TAME INT 14h handler 46h WORD offset of TAME INT 15h handler 48h WORD offset of TAME INT 16h handler 4Ah WORD offset of TAME INT 17h handler 4Ch WORD offset of TAME INT 21h handler 4Eh WORD offset of TAME INT 28h handler 50h WORD X in /max:X,Y or /freq:X,Y 52h WORD Y in /max:X,Y or /freq:X,Y 54h WORD number of polls remaining before next task switch 56h WORD /KEYIDLE value 58h 4 BYTEs ??? 5Ch WORD X in /boost:X,Y 5Eh WORD Y in /boost:X,Y 60h WORD /FG: value 62h WORD task switches left until next FGONLY DESQview API call 64h WORD multitasker version ??? 66h WORD virtual screen segment 68h BYTE interrupts already grabbed by TAME (see above) 69h BYTE flags for interrupts which may be acted on (same bits as above) 6Ah BYTE window or task number for this task 6Bh BYTE multitasker type 01h DESQview 02h DoubleDOS 03h TopView 04h OmniView 05h VM/386 6Ch BYTE type of task switching selected (bit flags) bit 0: DESQview bit 1: DoubleDOS bit 2: TopView bit 3: OmniView bit 4: KeySwitch bit 5: HLT instruction 6Dh BYTE watch_DOS 6Eh BYTE bit flags bit 0: TAME enabled bit 1: /FREQ instead of /MAX (counts in 50h and 52h per tick) bit 2: /TIMEPOLL bit 3: /KEYPOLL bit 4: inhibit timer bit 5: enable status monitoring 6Fh BYTE old status 70h WORD signature DA34h --------R-212B44BX4D41----------------------- INT 21 - pcANYWHERE IV/LAN - INSTALLATION CHECK AX = 2B44h ('D') BX = 4D41h ('MA') CX = 7063h ('pc') DX = 4157h ('AW') Return: AX = 4F4Bh ('OK') if large host resident = 6F6Bh ('ok') if small host resident CX:DX -> API entry point SeeAlso: INT 16/AH=79h Call API entry point with: AX = 0000h get pcANYWHERE IV version DS:SI -> BYTE buffer for host type code Return: AH = version number AL = revision number DS:DI buffer byte filled with 00h full-featured host 01h limited-feature LAN host other API may not be supported AX = 0001h initialize operation DS:SI -> initialization request structure (see below) Return: AX = function status (see below) AX = 0002h get status Return: AH = current operating mode (see init req structure below) AL = current connection status bit 0: a physical connection is active bit 1: remove screen updating is active bit 2: connection checking is active bit 3: hot key detection is active bit 4: background file transfer is active AX = 0003h suspend remote screen updates Return: AX = function status (see below) AX = 0004h resume screen updates Return: AX = function status (see below) AX = 0005h end current remote access session DS:SI -> termination request structure (see below) Return: AX = function status (see below) AX = 0006h remove pcANYWHERE IV from memory Return: AX = status 0000h successful FFD2h unable to release allocated memory FFD1h unable to release interrupt vectors AX = 8000h read data from communications channel DS:BX -> buffer CX = buffer size Return: AX >= number of characters read/available AX < 0 on error AX = 8001h write data to communications channel DS:BX -> buffer CX = buffer size Return: AX >= number of characters written AX < 0 on error AX = 8002h get connection status Return: AX = status > 0000h if connection active = 0000h if connection lost < 0000h on error Format of initialization request structure: Offset Size Description 00h BYTE operating mode 00h wait for a call 01h hot key activates 02h incoming call activates 03h initiate a call 01h 3 BYTEs user ID to append to config file names 04h WORD DS-relative pointer to path for config files 06h WORD DS-relative pointer to path for program files Format of termination request structure: Offset Size Description 00h BYTE operating mode after termination 00h wait for a call 01h hot key activates 02h incoming call activates 80h use current mode FFh remove from memory Values for function status: 0000h function completed successfully FFF2h unable to establish a connection when operating mode is "Initiate a call" FFF3h modem configuration is invalid (corrupt config) FFF4h modem initialization failed (no modem response) FFF5h the communications device could not be initialized FFF6h the host operator aborted the function FFF7h the communications driver type specified in the configuration file is different than the one loaded when pcANYWHERE IV was initially started FFF9h the configuration file is invalid FFFAh the configuration file could not be found FFFBh no session is active FFFCh a remote access session is active FFFDh the specified operating mode is invalid --------D-212C------------------------------- INT 21 - DOS 1+ - GET SYSTEM TIME AH = 2Ch Return: CH = hour CL = minute DH = second DL = 1/100 seconds Note: on most systems, the resolution of the system clock is about 5/100sec, so returned times generally do not increment by 1 on some systems, DL may always return 00h SeeAlso: AH=2Ah,AH=2Dh,AH=E7h,INT 1A/AH=00h,INT 1A/AH=02h,INT 1A/AH=FEh SeeAlso: INT 2F/AX=120Dh --------D-212D------------------------------- INT 21 - DOS 1+ - SET SYSTEM TIME AH = 2Dh CH = hour CL = minute DH = second DL = 1/100 seconds Return: AL = result 00h successful FFh invalid time, system time unchanged Note: DOS 3.3+ also sets CMOS clock SeeAlso: AH=2Bh"DOS",AH=2Ch,INT 1A/AH=01h,INT 1A/AH=03h,INT 1A/AH=FFh"AT&T" --------T-212D01CX7820----------------------- INT 21 - PC-Mix - INSTALLATION CHECK AX = 2D01h CX = 7820h ('X ') DX = 6D69h ('MI') Return: AL = 00h if installed --------D-212E--DL00------------------------- INT 21 - DOS 1+ - SET VERIFY FLAG AH = 2Eh DL = 00h (DOS 1.x/2.x only) AL = new state of verify flag 00h off 01h on Notes: default state at system boot is OFF when ON, all disk writes are verified provided the device driver supports read-after-write verification SeeAlso: AH=54h --------D-212F------------------------------- INT 21 - DOS 2+ - GET DISK TRANSFER AREA ADDRESS AH = 2Fh Return: ES:BX -> current DTA Note: under the FlashTek X-32 DOS extender, the pointer is in ES:EBX SeeAlso: AH=1Ah --------D-2130------------------------------- INT 21 - DOS 2+ - GET DOS VERSION AH = 30h ---DOS 5+ --- AL = what to return in BH 00h OEM number (as for DOS 2.0-4.0x) 01h version flag Return: AL = major version number (00h if DOS 1.x) AH = minor version number BL:CX = 24-bit user serial number (most versions do not use this) ---if DOS <5 or AL=00h--- BH = MSDOS OEM number (see below) ---if DOS 5+ and AL=01h--- BH = version flag bit 3: DOS is in ROM other: reserved (0) Notes: the OS/2 v1.x Compatibility Box returns major version 0Ah (10) the OS/2 v2.x Compatibility Box returns major version 14h (20) the Windows/NT DOS box returns version 5.00, subjet to SETVER DOS 4.01 and 4.02 identify themselves as version 4.00; use INT 21/AH=87h to distinguish between the original European MS-DOS 4.0 and the later PC-DOS 4.0x and MS-DOS 4.0x generic MS-DOS 3.30, Compaq MS-DOS 3.31, and others identify themselves as PC-DOS by returning OEM number 00h the version returned under DOS 4.0x may be modified by entries in the special program list (see AH=52h) the version returned under DOS 5+ may be modified by SETVER; use AX=3306h to get the true version number SeeAlso: AX=3000h/BX=3000h,AX=3306h,AX=4452h,AH=87h,INT 15/AX=4900h SeeAlso: INT 2F/AX=122Fh,INT 2F/AX=E002h Values for MSDOS OEM number: 00h IBM 01h Compaq??? 04h AT&T??? 05h Zenith 16h DEC 23h Olivetti 29h Toshiba 4Dh Hewlett-Packard 99h STARLITE architecture (OEM DOS, NETWORK DOS, SMP DOS) FFh Microsoft, Phoenix --------E-2130------------------------------- INT 21 - Phar Lap 386/DOS-Extender, Intel Code Builder - INSTALLATION CHECK AH = 30h EAX = 00003000h EBX = 50484152h ("PHAR") Return: AL = major DOS version AH = minor DOS version EAX bits 31-16 = 4458h ('DX') if 386/DOS-extender installed BL = ASCII major version number EAX bits 31-16 = 4243h ('BC') if Intel Code Builder installed EDX = address of GDA SeeAlso: AX=2501h,AX=FF00h,INT 2F/AX=F100h --------v-2130--DXABCD----------------------- INT 21 - VIRUS - "Possessed" - INSTALLATION CHECK AH = 30h DX = ABCDh Return: DX = DCBAh if installed SeeAlso: AX=0D20h,AX=30F1h --------T-213000BX1234----------------------- INT 21 - CTask 2.0+ - INSTALLATION CHECK AX = 3000h BX = 1234h DS:DX -> 8-byte version string (DX < FFF0h) "CTask21",00h for v2.1-2.2 Return: AL = DOS major version AH = DOS minor version CX:BX -> Ctask global data block Program: CTask is a multitasking kernel for C written by Thomas Wagner Note: if first eight bytes of returned data block equal eight bytes passed in, CTask is resident --------O-213000BX3000----------------------- INT 21 - PC-MOS/386 v3.0 - INSTALLATION CHECK/GET VERSION AX = 3000h BX = 3000h CX = DX = 3000h Return: AX = PC-MOS version Program: PC-MOS/386 is a multitasking/multiuser MS-DOS-compatible operating system by Software Links, Inc. SeeAlso: AH=30h,INT 38/AH=02h,INT 38/AH=10h --------v-2130F1----------------------------- INT 21 - VIRUS - "Dutch-555"/"Quit 1992" - INSTALLATION CHECK AX = 30F1h Return: AL = 00h if resident SeeAlso: AH=30h/DX=ABCDh,AX=330Fh ----------2130FFCX4445----------------------- INT 21 - DESQ??? - INSTALLATION CHECK AX = 30FFh CX = 4445h ("DE") DX = 5351h ("SQ") Return: BH = 05h if installed ??? Note: called by DUBLDISK.COM v2.6; this function is not supported by DESQview, so it may be for DESQview's precursor DESQ. SeeAlso: AX=4404h"DUBLDISK" --------D-2131------------------------------- INT 21 - DOS 2+ - TERMINATE AND STAY RESIDENT AH = 31h AL = return code DX = number of paragraphs to keep resident Return: never Notes: the value in DX only affects the memory block containing the PSP; additional memory allocated via AH=48h is not affected the minimum number of paragraphs which will remain resident is 11h for DOS 2.x and 06h for DOS 3+ most TSRs can save some memory by releasing their environment block before terminating (see AH=26h,AH=49h) SeeAlso: AH=00h,AH=4Ch,AH=4Dh,INT 20,INT 22,INT 27 --------D-2132------------------------------- INT 21 - DOS 2+ - GET DOS DRIVE PARAMETER BLOCK FOR SPECIFIC DRIVE AH = 32h DL = drive number (00h = default, 01h = A:, etc) Return: AL = status 00h successful DS:BX -> Drive Parameter Block (DPB) for specified drive FFh invalid or network drive Notes: the OS/2 compatibility box supports the DOS 3.3 version of this call except for the DWORD at offset 12h this call updates the DPB by reading the disk; the DPB may be accessed via the DOS list of lists (see AH=52h) if disk access is not desirable. undocumented prior to the release of DOS 5.0; only the DOS 4+ version of the DPB has been documented, however SeeAlso: AH=1Fh,AH=52h Format of DOS Drive Parameter Block: Offset Size Description 00h BYTE drive number (00h = A:, 01h = B:, etc) 01h BYTE unit number within device driver 02h WORD bytes per sector 04h BYTE highest sector number within a cluster 05h BYTE shift count to convert clusters into sectors 06h WORD number of reserved sectors at beginning of drive 08h BYTE number of FATs 09h WORD number of root directory entries 0Bh WORD number of first sector containing user data 0Dh WORD highest cluster number (number of data clusters + 1) 16-bit FAT if greater than 0FF6h, else 12-bit FAT 0Fh BYTE number of sectors per FAT 10h WORD sector number of first directory sector 12h DWORD address of device driver header 16h BYTE media ID byte 17h BYTE 00h if disk accessed, FFh if not 18h DWORD pointer to next DPB ---DOS 2.x--- 1Ch WORD cluster containing start of current directory, 0000h=root, FFFFh = unknown 1Eh 64 BYTEs ASCIZ pathname of current directory for drive ---DOS 3.x--- 1Ch WORD cluster at which to start search for free space when writing 1Eh WORD number of free clusters on drive, FFFFh = unknown ---DOS 4.0-6.0--- 0Fh WORD number of sectors per FAT 11h WORD sector number of first directory sector 13h DWORD address of device driver header 17h BYTE media ID byte 18h BYTE 00h if disk accessed, FFh if not 19h DWORD pointer to next DPB 1Dh WORD cluster at which to start search for free space when writing, usually the last cluster allocated 1Fh WORD number of free clusters on drive, FFFFh = unknown --------D-2133------------------------------- INT 21 - DOS 2+ - EXTENDED BREAK CHECKING AH = 33h AL = subfunction 00h get current extended break state Return: DL = current state, 00h = off, 01h = on 01h set state of extended ^C/^Break checking DL = 00h off, check only on character I/O functions 01h on, check on all DOS functions Note: under DOS 3.1+, this function does not use any of the DOS-internal and may thus be called at any time SeeAlso: AX=3302h --------D-213302----------------------------- INT 21 - DOS 3.x+ internal - GET AND SET EXTENDED CONTROL-BREAK CHECKING STATE AX = 3302h DL = new state 00h for OFF or 01h for ON Return: DL = old state of extended BREAK checking Note: this function does not use any of the DOS-internal stacks and may thus be called at any time; one possible use is modifying Control-Break checking from within an interrupt handler or TSR SeeAlso: AH=33h --------D-213305----------------------------- INT 21 - DOS 4+ - GET BOOT DRIVE AX = 3305h Return: DL = boot drive (1=A:,...) Notes: fully reentrant NEC 9800-series PCs always call the boot drive A: and assign the other drive letters sequentially to the other drives in the system --------D-213306----------------------------- INT 21 - DOS 5+ - GET TRUE VERSION NUMBER AX = 3306h Return: BL = major version BH = minor version DL = revision (bits 2-0, all others 0) DH = version flags bit 3: DOS is in ROM bit 4: DOS in in HMA Notes: this function always returns the true version number, unlike AH=30h, whose return value may be changed with SETVER because of the conflict from the CBIS PowerLAN redirector (see next entry), programs should check whether BH is less than 100 (64h) and BL is at least 5 before accepting the returned BX as the true version number; however, even this is not entirely reliable when that redirector is loaded fully reentrant OS/2 v2.1 will return BX=0A14h (version 20.10) the Windows NT DOS box returns BX=3205h (version 5.50)5 BUG: DR-DOS 5.0 and 6.0 return CF set/AX=0001h for INT 21/AH=33h subfunctions other than 00h-02h and 05h, while MS-DOS returns AL=FFh for invalid subfunctions SeeAlso: AH=30h,INT 2F/AX=112Fh --------N-213306----------------------------- INT 21 - CBIS POWERLAN - NETWORK REDIRECTOR - ??? AX = 3306h Return: AX = 3306h BL = ??? (usually 00h) BH = ??? (usually 00h or FFh) Note: unknown function, is in conflict with DOS 5+ version call SeeAlso: AX=3306h"DOS" --------v-21330F----------------------------- INT 21 - VIRUS - "Burghofer" - INSTALLATION CHECK AX = 330Fh Return: AL = 0Fh if resident (DOS returns AL=FFh) SeeAlso: AX=30F1h,AX=33E0h --------v-2133E0----------------------------- INT 21 - VIRUS - "Oropax" - INSTALLATION CHECK AX = 33E0h Return: AL = E0h if resident (DOS returns AL=FFh) SeeAlso: AX=330Fh,AX=357Fh --------D-2134------------------------------- INT 21 - DOS 2+ - GET ADDRESS OF INDOS FLAG AH = 34h Return: ES:BX -> one-byte InDOS flag Notes: the value of InDOS is incremented whenever an INT 21 function begins and decremented whenever one completes during an INT 28 call, it is safe to call some INT 21 functions even though InDOS may be 01h instead of zero InDOS alone is not sufficient for determining when it is safe to enter DOS, as the critical error handling decrements InDOS and increments the critical error flag for the duration of the critical error. Thus, it is possible for InDOS to be zero even if DOS is busy. the critical error flag is the byte immediately following InDOS in DOS 2.x, and the byte BEFORE the InDOS flag in DOS 3+ (except COMPAQ DOS 3.0, where the critical error flag is located 1AAh bytes BEFORE the critical section flag) For DOS 3.1+, an undocumented call exists to get the address of the critical error flag (see AX=5D06h) this function was undocumented prior to the release of DOS 5.0. SeeAlso: AX=5D06h,AX=5D0Bh,INT 15/AX=DE1Fh,INT 28 --------D-2135------------------------------- INT 21 - DOS 2+ - GET INTERRUPT VECTOR AH = 35h AL = interrupt number Return: ES:BX -> current interrupt handler Note: under DR-DOS 5.0, this function does not use any of the DOS-internal stacks and may thus be called at any time SeeAlso: AH=25h,AX=2503h --------E-213501----------------------------- INT 21 P - FlashTek X-32VM - ALLOCATE PROTECTED-MODE SELECTOR AX = 3501h Return: CF clear if successful BX = new selector CF set on error (no more selectors available) Note: the new selector will be an expand-up read/write data selector with undefined base and limit SeeAlso: AX=3502h,INT 31/AX=0000h --------E-213502----------------------------- INT 21 P - FlashTek X-32VM - DEALLOCATE PROTECTED-MODE SELECTOR AX = 3502h BX = selector Return: CF clear if successful CF set on error (invalid selector) Note: only selectors allocated via AX=3501h should be deallocated SeeAlso: AX=3501h,INT 31/AX=0001h --------E-213503----------------------------- INT 21 P - FlashTek X-32VM - SET SELECTOR BASE ADDRESS AX = 3503h BX = selector ECX = base address Return: CF clear if successful CF set on error (invalid selector) SeeAlso: AX=3504h,AX=3505h,INT 31/AX=0007h --------E-213504----------------------------- INT 21 P - FlashTek X-32VM - GET SELECTOR BASE ADDRESS AX = 3504h BX = selector Return: CF clear if successful ECX = absolute base address of selector CF set on error (invalid selector) SeeAlso: AX=3503h,INT 31/AX=0006h --------E-213505----------------------------- INT 21 P - FlashTek X-32VM - SET SELECTOR LIMIT AX = 3505h BX = selector ECX = desired limit Return: CF clear if successful ECX = actual limit set CF set on error (no more selectors available) Note: the limit will be rounded down to nearest 4K boundary if the requested limit is greater than 1MB SeeAlso: AX=3503h,INT 31/AX=0008h --------E-21350A----------------------------- INT 21 P - FlashTek X-32VM - PHYSICAL ADDRESS MAPPING AX = 350Ah EBX = absolute physical address ECX = size in bytes of area to map Return: CF clear if successful CF set on error (insufficient memory or service refused by DPMI host) Notes: should not make repeated calls for the same physical address there is no provision for unmapping memory --------E-21350B----------------------------- INT 21 P - FlashTek X-32VM - UPDATE AND RETURN AVAILABLE FREE MEMORY AX = 350Bh DS = default selector for DS Return: CF clear EAX = maximum amount of memory which can be allocated via AX=350Ch SeeAlso: AX=350Ch --------E-21350C----------------------------- INT 21 P - FlashTek X-32VM - ALLOCATE A BLOCK OF MEMORY AX = 350Ch ECX = size of block in bytes DS = default DS Return: CF clear if successful EAX = near pointer to new block EDX = new lowest legal value for stack CF set on error (requested size not multiple of 4K) SeeAlso: AX=350Bh,AX=350Dh --------E-21350D----------------------------- INT 21 P - FlashTek X-32VM - RESERVE BLOCK OF MEMORY FOR 32-BIT STACK AX = 350Dh EBX = current ESP value ECX = size of block in bytes DS = default DS Return: CF clear if successful EBX = new value for ESP EDX = suggested new limit for SS CF set on error Note: this function should only be called once during initialization SeeAlso: AX=350Bh,AX=350Ch --------v-21357F----------------------------- INT 21 - VIRUS - "Agiplan"/"Month 4-6" - INSTALLATION CHECK AX = 357Fh Return: DX = FFFFh if installed SeeAlso: AX=33E0h,AX=3DFFh --------D-2136------------------------------- INT 21 - DOS 2+ - GET FREE DISK SPACE AH = 36h DL = drive number (00h = default, 01h = A:, etc) Return: AX = FFFFh if invalid drive else AX = sectors per cluster BX = number of free clusters CX = bytes per sector DX = total clusters on drive Notes: free space on drive in bytes is AX * BX * CX total space on drive in bytes is AX * CX * DX "lost clusters" are considered to be in use according to Dave Williams' MS-DOS reference, the value in DX is incorrect for non-default drives after ASSIGN is run SeeAlso: AH=1Bh,AH=1Ch --------D-213700----------------------------- INT 21 - DOS 2+ - "SWITCHAR" - GET SWITCH CHARACTER AX = 3700h Return: AL = status 00h successful DL = current switch character FFh unsupported subfunction Desc: Determine the character which is used to introduce command switches. This setting is ignored by DOS commands in version 4.0 and higher, but is honored by many third-party programs. Notes: documented in some OEM versions of some releases of DOS supported by OS/2 compatibility box always returns DL=2Fh for DOS 5+ SeeAlso: AX=3701h --------D-213701----------------------------- INT 21 - DOS 2+ - "SWITCHAR" - SET SWITCH CHARACTER AX = 3701h DL = new switch character Return: AL = status 00h successful FFh unsupported subfunction Notes: documented in some OEM versions of some releases of DOS supported by OS/2 compatibility box ignored by DOS 5+ SeeAlso: AX=3700h --------D-2137------------------------------- INT 21 - DOS 2.x and 3.3+ only - "AVAILDEV" - SPECIFY \DEV\ PREFIX USE AH = 37h AL = subfunction 02h get availdev flag Return: DL = 00h \DEV\ must precede character device names = nonzero \DEV\ is optional 03h set availdev flag DL = 00h \DEV\ is mandatory = nonzero \DEV\ is optional Return: AL = status 00h successful FFh unsupported subfunction Notes: all versions of DOS from 2.00 allow \DEV\ to be prepended to device names without generating an error even if the directory \DEV does not actually exist (other paths generate an error if they do not exist). although DOS 3.3+ accepts these calls, they have no effect, and AL=02h always returns DL=FFh --------D-2138------------------------------- INT 21 - DOS 2+ - GET COUNTRY-SPECIFIC INFORMATION AH = 38h --DOS 2.x-- AL = 00h get current-country info DS:DX -> buffer for returned info (see below) Return: CF set on error AX = error code (02h) CF clear if successful AX = country code (MS-DOS 2.11 only) buffer at DS:DX filled --DOS 3+-- AL = 00h for current country AL = 01h thru 0FEh for specific country with code <255 AL = 0FFh for specific country with code >= 255 BX = 16-bit country code DS:DX -> buffer for returned info (see below) Return: CF set on error AX = error code (02h) CF clear if successful BX = country code DS:DX buffer filled SeeAlso: AH=65h,INT 10/AX=5001h,INT 2F/AX=110Ch,INT 2F/AX=1404h Format of PC-DOS 2.x country info: Offset Size Description 00h WORD date format 0 = USA mm dd yy 1 = Europe dd mm yy 2 = Japan yy mm dd 02h BYTE currency symbol 03h BYTE 00h 04h BYTE thousands separator char 05h BYTE 00h 06h BYTE decimal separator char 07h BYTE 00h 08h 24 BYTEs reserved Format of MS-DOS 2.x,DOS 3+ country info: Offset Size Description 00h WORD date format (see above) 02h 5 BYTEs ASCIZ currency symbol string 07h 2 BYTEs ASCIZ thousands separator 09h 2 BYTEs ASCIZ decimal separator 0Bh 2 BYTEs ASCIZ date separator 0Dh 2 BYTEs ASCIZ time separator 0Fh BYTE currency format bit 2 = set if currency symbol replaces decimal point bit 1 = number of spaces between value and currency symbol bit 0 = 0 if currency symbol precedes value 1 if currency symbol follows value 10h BYTE number of digits after decimal in currency 11h BYTE time format bit 0 = 0 if 12-hour clock 1 if 24-hour clock 12h DWORD address of case map routine (FAR CALL, AL = character to map to upper case [>= 80h]) 16h 2 BYTEs ASCIZ data-list separator 18h 10 BYTEs reserved Values for country code: 001h United States 002h Canadian-French 003h Latin America 01Fh Netherlands 020h Belgium 021h France 022h Spain 024h Hungary (not supported by DR-DOS 5.0) 026h Yugoslavia (not supported by DR-DOS 5.0) 027h Italy 029h Switzerland 02Ah Czechoslovakia (not supported by DR-DOS 5.0) 02Bh Austria (DR-DOS 5.0) 02Ch United Kingdom 02Dh Denmark 02Eh Sweden 02Fh Norway 030h Poland (not supported by DR-DOS 5.0) 031h Germany 037h Brazil (not supported by DR-DOS 5.0) 03Dh International English [Australia in DR-DOS 5.0] 051h Japan (DR-DOS 5.0) 052h Korea (DR-DOS 5.0) 15Fh Portugal 166h Finland 311h Middle East (DR-DOS 5.0) 3CCh Israel (DR-DOS 5.0) --------D-2138--DXFFFF----------------------- INT 21 - DOS 3+ - SET COUNTRY CODE AH = 38h DX = FFFFh AL = 01h thru FEh for specific country with code <255 AL = FFh for specific country with code >= 255 BX = 16-bit country code (see AH=38h) Return: CF set on error AX = error code (see AH=59h) CF clear if successful Note: not supported by OS/2 SeeAlso: INT 2F/AX=1403h --------D-2139------------------------------- INT 21 - DOS 2+ - "MKDIR" - CREATE SUBDIRECTORY AH = 39h DS:DX -> ASCIZ pathname Return: CF clear if successful AX destroyed CF set on error AX = error code (03h,05h) (see AH=59h) Notes: all directories in the given path except the last must exist fails if the parent directory is the root and is full DOS 2.x-3.3 allow the creation of a directory sufficiently deep that it is not possible to make that directory the current directory because the path would exceed 64 characters under the FlashTek X-32 DOS extender, the pointer is in DS:EDX SeeAlso: AH=3Ah,AH=3Bh,AH=6Dh,AH=E2h/SF=0Ah,INT 2F/AX=1103h --------D-213A------------------------------- INT 21 - DOS 2+ - "RMDIR" - REMOVE SUBDIRECTORY AH = 3Ah DS:DX -> ASCIZ pathname of directory to be removed Return: CF clear if successful AX destroyed CF set on error AX = error code (03h,05h,06h,10h) (see AH=59h) Notes: directory must be empty (contain only '.' and '..' entries) under the FlashTek X-32 DOS extender, the pointer is in DS:EDX SeeAlso: AH=39h,AH=3Bh,AH=E2h/SF=0Bh,INT 2F/AX=1101h --------D-213B------------------------------- INT 21 - DOS 2+ - "CHDIR" - SET CURRENT DIRECTORY AH = 3Bh DS:DX -> ASCIZ pathname to become current directory (max 64 bytes) Return: CF clear if successful AX destroyed CF set on error AX = error code (03h) (see AH=59h) Notes: if new directory name includes a drive letter, the default drive is not changed, only the current directory on that drive changing the current directory also changes the directory in which FCB file calls operate under the FlashTek X-32 DOS extender, the pointer is in DS:EDX SeeAlso: AH=47h,INT 2F/AX=1105h --------D-213C------------------------------- INT 21 - DOS 2+ - "CREAT" - CREATE OR TRUNCATE FILE AH = 3CH CX = file attributes (see below) DS:DX -> ASCIZ filename Return: CF clear if successful AX = file handle CF set on error AX = error code (03h,04h,05h) (see AH=59h) Notes: if a file with the given name exists, it is truncated to zero length under the FlashTek X-32 DOS extender, the pointer is in DS:EDX SeeAlso: AH=16h,AH=3Dh,AH=5Ah,AH=5Bh,AH=93h,INT 2F/AX=1117h Bitfields for file attributes: bit 0 read-only bit 1 hidden bit 2 system bit 3 volume label (ignored) bit 4 reserved, must be zero (directory) bit 5 archive bit bit 7 if set, file is shareable under Novell NetWare --------D-213D------------------------------- INT 21 - DOS 2+ - "OPEN" - OPEN EXISTING FILE AH = 3Dh AL = access and sharing modes (see below) DS:DX -> ASCIZ filename CL = attribute mask of files to look for (server call only) Return: CF clear if successful AX = file handle CF set on error AX = error code (01h,02h,03h,04h,05h,0Ch) (see AH=59h) Notes: file pointer is set to start of file file handles which are inherited from a parent also inherit sharing and access restrictions files may be opened even if given the hidden or system attributes under the FlashTek X-32 DOS extender, the pointer is in DS:EDX SeeAlso: AH=0Fh,AH=3Ch,AX=4301h,AX=5D00h,INT 2F/AX=1116h,INT 2F/AX=1226h Bitfields for access and sharing modes: bits 2-0 access mode 000 read only 001 write only 010 read/write 011 (DOS 5+ internal) passed to redirector on EXEC to allow case-sensitive filenames bit 3 reserved (0) bits 6-4 sharing mode (DOS 3+) 000 compatibility mode 001 "DENYALL" prohibit both read and write access by others 010 "DENYWRITE" prohibit write access by others 011 "DENYREAD" prohibit read access by others 100 "DENYNONE" allow full access by others bit 7 inheritance if set, file is private to current process and will not be inherited by child processes File sharing behavior: | Second and subsequent Opens First |Compat Deny Deny Deny Deny Open | All Write Read None |R W RW R W RW R W RW R W RW R W RW - - - - -| - - - - - - - - - - - - - - - - - Compat R |Y Y Y N N N 1 N N N N N 1 N N W |Y Y Y N N N N N N N N N N N N RW|Y Y Y N N N N N N N N N N N N - - - - -| Deny R |C C C N N N N N N N N N N N N All W |C C C N N N N N N N N N N N N RW|C C C N N N N N N N N N N N N - - - - -| Deny R |2 C C N N N Y N N N N N Y N N Write W |C C C N N N N N N Y N N Y N N RW|C C C N N N N N N N N N Y N N - - - - -| Deny R |C C C N N N N Y N N N N N Y N Read W |C C C N N N N N N N Y N N Y N RW|C C C N N N N N N N N N N Y N - - - - -| Deny R |2 C C N N N Y Y Y N N N Y Y Y None W |C C C N N N N N N Y Y Y Y Y Y RW|C C C N N N N N N N N N Y Y Y Legend: Y = open succeeds, N = open fails with error code 05h C = open fails, INT 24 generated 1 = open succeeds if file read-only, else fails with error code 2 = open succeeds if file read-only, else fails with INT 24 --------v-213DFF----------------------------- INT 21 - VIRUS - "JD-448" - INSTALLATION CHECK AX = 3DFFh Return: AX = 4A44h if resident SeeAlso: AX=357Fh,AX=4203h --------D-213E------------------------------- INT 21 - DOS 2+ - "CLOSE" - CLOSE FILE AH = 3Eh BX = file handle Return: CF clear if successful AX destroyed CF set on error AX = error code (06h) (see AH=59h) Note: if the file was written to, any pending disk writes are performed, the time and date stamps are set to the current time, and the directory entry is updated SeeAlso: AH=10h,AH=3Ch,AH=3Dh,INT 2F/AX=1106h,INT 2F/AX=1227h --------D-213F------------------------------- INT 21 - DOS 2+ - "READ" - READ FROM FILE OR DEVICE AH = 3Fh BX = file handle CX = number of bytes to read DS:DX -> buffer for data Return: CF clear if successful AX = number of bytes actually read (0 if at EOF before call) CF set on error AX = error code (05h,06h) (see AH=59h) Notes: data is read beginning at current file position, and the file position is updated after a successful read the returned AX may be smaller than the request in CX if a partial read occurred if reading from CON, read stops at first CR under the FlashTek X-32 DOS extender, the pointer is in DS:EDX SeeAlso: AH=27h,AH=40h,AH=93h,INT 2F/AX=1108h,INT 2F/AX=1229h --------G-213F------------------------------- INT 21 - Turbo Debug HARDWARE BREAKPOINTS - READ STATUS BLOCK AH = 3Fh BX = handle for character device "TDHDEBUG" CX = number of bytes to read DS:DX -> buffer for status block (see below) Return: CF clear if successful AX = number of bytes actually read CF set on error AX = error code (05h,06h) (see AH=59h) SeeAlso: AH=40h"Turbo Debug" Format of status block: Offset Size Description 00h BYTE status of command 00h successful 01h invalid handle 02h no more breakpoints available 03h hardware does not support specified breakpoint type 04h previous command prevents execution 05h debugger hardware not found 06h hardware failure 07h invalid command 08h driver not initialized yet FEh recursive entry (hardware breakpoint inside hw bp handler) ---status for command 01h--- 01h WORD device driver interface version number (currently 1) 03h WORD device driver software version 05h BYTE maximum simultaneous hardware breakpoints 06h BYTE configuration bits bit 0: CPU and DMA accesses are distinct bit 1: can detect DMA transfers bit 2: supports data mask bit 3: hardware pass counter on breakpoints bit 4: can match on data as well as addresses 07h BYTE supported breakpoint types (see below) 08h WORD supported addressing match modes (see below) 0Ah WORD supported data matches (see below) 0Ch BYTE maximum data match length (01h, 02h, or 04h) 0Dh WORD size of onboard memory (in K) 0Fh WORD maximum number of trace-back events 11h WORD hardware breakpoint enable byte address segment (0000h if not supported) ---status for command 04h--- 01h BYTE handle to use when referring to the just-set breakpoint Bitfields for supported breakpoint types: bit 0 memory read bit 1 memory write bit 2 memory read/write bit 3 I/O read bit 4 I/O write bit 5 I/O read/write bit 6 instruction fetch Bitfields for supported addressing match modes: bit 0 any address bit 1 equal to test value bit 2 not equal bit 3 above test value bit 4 below test value bit 5 below or equal bit 6 above or equal bit 7 within range bit 8 outside range Bitfields for supported data matches: bit 0 any data bit 1 equal to test value bit 2 not equal bit 3 above test value bit 4 below test value bit 5 below or equal bit 6 above or equal bit 7 within range bit 8 outside range --------N-213F------------------------------- INT 21 - PC/TCP IPCUST.SYS - READ CONFIGURATION DATA AH = 3Fh BX = handle for character device "$IPCUST" CX = number of bytes to read DS:DX -> buffer for configuration data (see below) Return: CF clear if successful AX = number of bytes actually read CF set on error AX = error code (05h,06h) (see AH=59h) Notes: if less than the entire data is read or written, the next read/write continues where the previous one ended; IOCTL calls AX=4402h and AX=4403h both reset the location at which the next operation starts to zero the data pointer is also reset to zero if the previous read or write reached or exceeded the end of the data, when the current function is read and the previous was write, or vice versa v2.1+ uses a new configuration method, but allows the installation of IPCUST.SYS for backward compatibility with other software which must read the PC/TCP configuration SeeAlso: AH=40h"IPCUST",AX=4402h"IPCUST" Format of configuration data: Offset Size Description 00h 12 BYTEs IPCUST.SYS device driver header 12h BYTE ??? 13h BYTE ??? 14h WORD ??? 16h BYTE bit flags bit 0: send BS rather than DEL for BackSpace key bit 1: wrap long lines 17h BYTE ??? 18h 64 BYTEs ASCIZ hostname 58h 64 BYTEs ASCIZ domain name (fully qualified domain name is hostname.domain-name) 98h 16 BYTEs ASCIZ username A8h 64 BYTEs ASCIZ full name E8h 64 BYTEs ASCIZ office address 128h 32 BYTEs ASCIZ phone number 148h WORD offset from GMT in minutes 14Ah 4 BYTEs ASCIZ timezone name 14Eh WORD number of time servers 150h ? DWORDs IP addresses for time servers (big-endian) ??? 164h WORD number of old-style name servers 166h 3 DWORDs IP addresses for name servers (big-endian) 172h WORD number of domain name servers 174h 3 DWORDs IP addresses for domain name servers (big-endian) 180h DWORD IP address of default gateway (big-endian) 184h DWORD IP address of log server (big-endian) 188h DWORD IP address of cookie server (big-endian) 18Ch DWORD IP address of lpr server (big-endian) 190h DWORD IP address of imagen print server 194h 54 BYTEs ??? 1E8h WORD TCP default window size in bytes 1EAh WORD TCP low window size 1ECh 64 BYTEs ASCIZ host tabel filename 22Ch 2 BYTEs ??? 22Eh 80 BYTEs ASCIZ mail relay host name 27Eh BYTE ??? 27Fh BYTE ??? bit flags 280h 44 BYTEs ??? 2ACh WORD ??? 2AEh 202 BYTEs ??? --------N-213F------------------------------- INT 21 - WORKGRP.SYS - GET ENTRY POINT AH = 3Fh BX = file handle for device "NET$HLP$" CX = 0008h DS:DX -> buffer for entry point record (see AX=4402h"WORKGRP.SYS") Return: CF clear if successful AX = number of bytes actually read (0 if at EOF before call) CF set on error AX = error code (05h,06h) (see AH=59h) Program: WORKGRP.SYS is distributed with MS-DOS 6.0 to permit communication with PCs running Windows for Workgroups or LAN Manager SeeAlso: AX=4402h"WORKGRP.SYS",INT 2F/AX=9400h --------D-2140------------------------------- INT 21 - DOS 2+ - "WRITE" - WRITE TO FILE OR DEVICE AH = 40h BX = file handle CX = number of bytes to write DS:DX -> data to write Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (05h,06h) (see AH=59h) Notes: if CX is zero, no data is written, and the file is truncated or extended to the current position data is written beginning at the current file position, and the file position is updated after a successful write the usual cause for AX < CX on return is a full disk BUG: a write of zero bytes will appear to succeed when it actually failed if the write is extending the file and there is not enough disk space for the expanded file (DOS 5.0-6.0); one should therefore check whether the file was in fact extended by seeking to 0 bytes from the end of the file (INT 21/AX=4202h/CX=0/DX=0) under the FlashTek X-32 DOS extender, the pointer is in DS:EDX SeeAlso: AH=28h,AH=3Fh,AH=93h,INT 2F/AX=1109h --------G-2140------------------------------- INT 21 - Turbo Debug HARDWARE BREAKPOINTS - SEND CMD TO HARDWARE BRKPNT DRIVER AH = 40h BX = handle for character device "TDHDEBUG" CX = number of bytes to write DS:DX -> hardware breakpoint command (see below) Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (05h,06h) (see AH=59h) Note: results are retrieved by reading from the device SeeAlso: AH=3Fh"Turbo Debug" Format of hardware breakpoint commands: Offset Size Description 00h BYTE command code 00h install interrupt vectors 01h get hardware capabilities 02h enable hardware breakpoints 03h disable hardware breakpoints 04h set hardware breakpoint 05h clear hardware breakpoint 06h set I/O base address and reset hardware 07h restore interrupt vectors ---command code 00h--- 01h DWORD pointer to Turbo Debugger entry point to be jumped to on hardware breakpoint; call with CPU state the same as on the breakpoint except for pushing AX and placing an entry code (FFh if breakout button or breakpoint handle) in AH ---command code 04h--- 01h BYTE breakpoint type 00h memory read 01h memory write 02h memory read/write 03h I/O read 04h I/O write 05h I/O read/write 06h instruction fetch 02h BYTE address matching mode 00h any address 01h equal to test value 02h different from test value 03h above test value 04h below test value 05h below or equal to test value 06h above or equal to test value 07h within inclusive range 08h outside specified range 03h DWORD 32-bit linear low address 07h DWORD 32-bit linear high address 0Bh WORD pass count 0Dh BYTE data size (01h, 02h, or 04h) 0Eh BYTE source of matched bus cycle 01h CPU 02h DMA 03h either 0Fh BYTE data-matching mode 00h match any 01h equal to test value 02h different from test value 03h above test value 04h below test value 05h below or equal to test value 06h above or equal to test value 07h within specified range 08h outside specified range 10h DWORD low data value 14h DWORD high data value 18h DWORD data mask specifying which bits of the data are tested ---command code 05h--- 01h BYTE handle of breakpoint to clear (breakpoint returned from command 04h) ---command code 06h--- 01h WORD base address of hardware debugger board --------N-2140------------------------------- INT 21 - PC/TCP IPCUST.SYS - WRITE CONFIGURATION DATA AH = 40h BX = handle for character device "$IPCUST" CX = number of bytes to write DS:DX -> buffer for configuration data (AH=3Fh"IPCUST") Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (05h,06h) (see AH=59h) Notes: if less than the entire data is read or written, the next read/write continues where the previous one ended; IOCTL calls AX=4402h and AX=4403h both reset the location at which the next operation starts to zero the data pointer is also reset to zero if the previous read or write reached or exceeded the end of the data, when the current function is read and the previous was write, or vice versa v2.1+ uses a new configuration method, but allows the installation of IPCUST.SYS for backward compatibility with other software which must read the PC/TCP configuration SeeAlso: AH=3Fh"IPCUST",AX=4402h"IPCUST" --------j-214000BX0002----------------------- INT 21 - FARTBELL.EXE - INSTALLATION CHECK AX = 4000h BX = 0002h CX = 0000h DS:DX = 0000h:0000h Return: CF clear if installed AX = CS of resident code Program: FARTBELL is a joke program by Guenther Thiele which makes various noises when programs output a bell SeeAlso: AX=4001h --------j-214001BX0002----------------------- INT 21 - FARTBELL.EXE - FORCE NOISE AX = 4001h BX = 0002h CX = 0000h DS:DX = 0000h:0000h Program: FARTBELL is a joke program by Guenther Thiele which makes various noises when programs output a bell SeeAlso: AX=4000h --------D-2141------------------------------- INT 21 - DOS 2+ - "UNLINK" - DELETE FILE AH = 41h DS:DX -> ASCIZ filename (no wildcards, but see below) CL = attribute mask for deletion (server call only, see below) Return: CF clear if successful AX destroyed (DOS 3.3) AL seems to be drive of deleted file CF set on error AX = error code (02h,03h,05h) (see AH=59h) Notes: (DOS 3.1+) wildcards are allowed if invoked via AX=5D00h, in which case the filespec must be canonical (as returned by AH=60h), and only files matching the attribute mask in CL are deleted DOS does not erase the file's data; it merely becomes inaccessible because the FAT chain for the file is cleared deleting a file which is currently open may lead to filesystem corruption. Unless SHARE is loaded, DOS does not close the handles referencing the deleted file, thus allowing writes to a nonexistant file. under DRDOS and DR Multiuser DOS, this function will fail if the file is currently open under the FlashTek X-32 DOS extender, the pointer is in DS:EDX SeeAlso: AH=13h,AX=4301h,AX=5D00h,AH=60h,AX=F244h,INT 2F/AX=1113h --------y-214101DXFFFE----------------------- INT 21 - SoftLogic Data Guardian - ??? AX = 4101h DX = FFFEh Return: AX = 0000h if installed Note: resident code sets several internal variables on this call --------D-2142------------------------------- INT 21 - DOS 2+ - "LSEEK" - SET CURRENT FILE POSITION AH = 42h AL = origin of move 00h start of file 01h current file position 02h end of file BX = file handle CX:DX = offset from origin of new file position Return: CF clear if successful DX:AX = new file position in bytes from start of file CF set on error AX = error code (01h,06h) (see AH=59h) Notes: for origins 01h and 02h, the pointer may be positioned before the start of the file; no error is returned in that case, but subsequent attempts at I/O will produce errors if the new position is beyond the current end of file, the file will be extended by the next write (see AH=40h) BUG: using this method to grow a file from zero bytes to a very large size can corrupt the FAT in some versions of DOS; the file should first be grown from zero to one byte and then to the desired large size SeeAlso: AH=24h,INT 2F/AX=1228h --------v-214203----------------------------- INT 21 - VIRUS - "Shake" - INSTALLATION CHECK AX = 4203h Return: AX = 1234h if resident SeeAlso: AX=3DFFh,AX=4243h --------v-214243----------------------------- INT 21 - VIRUS - "Invader" - INSTALLATION CHECK AX = 4243h Return: AX = 5678h if resident SeeAlso: AX=4203h,AX=4B04h --------D-214300----------------------------- INT 21 - DOS 2+ - GET FILE ATTRIBUTES AX = 4300h DS:DX -> ASCIZ filename Return: CF clear if successful CX = file attributes (see AX=4301h) AX = CX (DR-DOS 5.0) CF set on error AX = error code (01h,02h,03h,05h) (see AH=59h) Note: under the FlashTek X-32 DOS extender, the filename pointer is in DS:EDX SeeAlso: AX=4301h,AX=4310h,AH=B6h,INT 2F/AX=110Fh --------D-214301----------------------------- INT 21 - DOS 2+ - "CHMOD" - SET FILE ATTRIBUTES AX = 4301h CX = new file attributes (see below) DS:DX -> ASCIZ filename Return: CF clear if successful AX destroyed CF set on error AX = error code (01h,02h,03h,05h) (see AH=59h) Notes: will not change volume label or directory attribute bits, but will change the other attribute bits of a directory (the directory bit must be cleared to successfully change the other attributes of a directory, but the directory will not be changed to a normal file as a result) MS-DOS 4.01 reportedly closes the file if it is currently open for security reasons, the Novell NetWare execute-only bit can never be cleared; the file must be deleted and recreated under the FlashTek X-32 DOS extender, the filename pointer is in DS:EDX DOS 5.0 SHARE will close the file if it is currently open in sharing- compatibility mode, otherwise a sharing violation critical error is generated if the file is currently open SeeAlso: AX=4300h,AX=4311h,INT 2F/AX=110Eh Bitfields for file attributes: bit 7 shareable (Novell NetWare) bit 6 unused bit 5 archive bit 4 directory bit 3 volume label execute-only (Novell NetWare) bit 2 system bit 1 hidden bit 0 read-only --------O-214302----------------------------- INT 21 - DR-DOS 3.41+ internal - GET ACCESS RIGHTS AX = 4302h DS:DX -> ASCIZ pathname Return: CF clear if successful CX = access rights (see below) AX = CX (DR-DOS 5.0) CF set on error AX = error code Desc: Determine which operations the calling program may perform on a specified file without being required to provide a password. Notes: this protection scheme has been coordinated on all current Digital Research/Novell operating systems (DR-DOS 3.41+, DRMDOS 5.x, and FlexOS 2+) this function is documented in DR-DOS 6.0 and corresponds to the "Get/Set File Attributes" function, subfunction 2, documented in Concurrent DOS. only FlexOS actually uses the "execution" bits; DR-DOS 3.41+ treats them as "read" bits. DR-DOS 3.41-5.x only use bits 0-3. Only DR-DOS 6.0 using a DRMDOS 5.x security system allowing for users and groups uses bits 4-11. SeeAlso: AX=4303h Bitfields for access rights: bit 0 owner delete requires password bit 1 owner execution requires password (FlexOS) bit 2 owner write requires password bit 3 owner read requires password bit 4 group delete requires password bit 5 group execution requires password (FlexOS) bit 6 group write requires password bit 7 group read requires password bit 8 world delete requires password bit 9 world execution requires password (FlexOS) bit 10 world write requires password bit 11 world read requires password --------O-214303----------------------------- INT 21 - DR-DOS 3.41+ internal - SET ACCESS RIGHTS AND PASSWORD AX = 4303h CX = access rights bits 11-0: access rights (see AX=4302h) bit 15: new password is to be set DS:DX -> ASCIZ pathname [DTA] = new password if CX bit 15 is set (blank-padded to 8 characters) Return: CF clear if successful CF set on error AX = error code Notes: if the file is already protected, the old password must be added after the pathname, separated by a ";" this function is documented in DR-DOS 6.0 and corresponds to the "Get/Set File Attributes" function, subfunction 3, documented in Concurrent DOS. SeeAlso: AX=4302h,AX=4305h,AX=4454h --------O-214304----------------------------- INT 21 - DR-DOS 5.0-6.0 internal - GET ENCRYPTED PASSWORD AX = 4304h ??? Return: CF clear if successful CX = AX = ??? CF set on error AX = error code (see AH=59h) Note: this function is only supported by DR-DOS 5.0 and 6.0 and DRMDOS 5.1 SeeAlso: AX=4303h,AX=4305h --------O-214305----------------------------- INT 21 - DR-DOS 5.0-6.0 internal - SET EXTENDED FILE ATTRIBUTES AX = 4305h ??? Return: CF clear if successful CF set on error AX = error code (see AH=59h) Desc: this function allows the extended attributes, and optionally the encrypted password, of a file to be set. Note: this function is only supported by DR-DOS 5.0 and 6.0 and DRMDOS 5.1 SeeAlso: AX=4304h,AX=4311h --------O-214306----------------------------- INT 21 - DR-DOS 6.0 - GET FILE OWNER AX = 4306h ??? Return: ??? SeeAlso: AX=4307h --------O-214307----------------------------- INT 21 - DR-DOS 6.0 - SET FILE OWNER AX = 4307h ??? Return: ??? SeeAlso: AX=4306h --------N-214310----------------------------- INT 21 - Banyan VINES 2.1+ - GET EXTENDED FILE ATTRIBUTES AX = 4310h DS:DX -> ASCIZ filename Return: CF clear if successful CH = attributes (see AX=4311h) CF set on error AX = error code (01h,02h,03h,05h) (see AH=59h) Note: the filename may be a directory but must be on a VINES file service SeeAlso: AX=4300h,AX=4311h,AH=B6h,INT 2F/AX=110Fh --------N-214311----------------------------- INT 21 - Banyan VINES 2.1+ - SET EXTENDED FILE ATTRIBUTES AX = 4311h CH = new attributes bit 7: unused bit 6: shareable bit 5: execute-only bits 4-0: unused DS:DX -> ASCIZ filename Return: CF clear if successful CF set on error AX = error code (01h,02h,03h,05h) (see AH=59h) Note: the filename may be a directory but must be on a VINES file service SeeAlso: AX=4301h,AX=4305h,AX=4310h,INT 2F/AX=110Eh --------D-214400----------------------------- INT 21 - DOS 2+ - IOCTL - GET DEVICE INFORMATION AX = 4400h BX = handle Return: CF clear if successful DX = device information word (see below) AX destroyed CF set on error AX = error code (01h,05h,06h) (see AH=59h) Notes: value in DH corresponds to high byte of device driver's attribute word if handle refers to a character device Novell NetWare reportedly does not return a drive number in bits 5-0 for a disk file SeeAlso: AX=4401h,INT 2F/AX=122Bh Bitfields for device information word: character device bit 14: device driver can process IOCTL requests (see AX=4402h) bit 13: output until busy supported bit 11: driver supports OPEN/CLOSE calls bit 7: set (indicates device) bit 6: EOF on input bit 5: raw (binary) mode bit 4: device is special (uses INT 29) bit 3: clock device bit 2: NUL device bit 1: standard output bit 0: standard input disk file bit 15: file is remote (DOS 3+) bit 14: don't set file date/time on closing (DOS 3+) bit 11: media not removable bit 8: (DOS 4 only) generate INT 24 if no disk space on write or read past end of file bit 7: clear (indicates file) bit 6: file has not been written bits 5-0: drive number (0 = A:) --------D-214401----------------------------- INT 21 - DOS 2+ - IOCTL - SET DEVICE INFORMATION AX = 4401h BX = handle (must refer to character device) DX = device information word (see AX=4400h) (DH must be zero) Return: CF clear if successful CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4400h,INT 2F/AX=122Bh --------D-214402----------------------------- INT 21 - DOS 2+ - IOCTL - READ FROM CHARACTER DEVICE CONTROL CHANNEL AX = 4402h BX = file handle referencing character device CX = number of bytes to read DS:DX -> buffer Return: CF clear if successful AX = number of bytes actually read CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: format of data is driver-specific (see below for some specific cases) SeeAlso: AX=4400h,AX=4403h,AX=4404h,INT 2F/AX=122Bh --------N-214402----------------------------- INT 21 - Network Driver Interface Spec 2.0.1 - PROTOCOL MANAGER AX = 4402h BX = file handle for device "PROTMAN$" DS:DX -> request block (see below) CX = 000Eh (size of request block) Format of request block for GetProtocolManagerInfo: Offset Size Description 00h WORD 01h 02h WORD returned status (see below) 04h DWORD returned pointer to structure representing parsed user config 08h DWORD unused 0Ch WORD returned BCD version of NDIS on which Protocol Manager is based Format of request block for RegisterModule: Offset Size Description 00h WORD 02h 02h WORD returned status (see below) 04h DWORD pointer to module's common characteristics table (see below) 08h DWORD pointer to list of modules to which the module is to be bound 0Ch WORD unused Format of request block for BindAndStart: Offset Size Description 00h WORD 03h 02h WORD returned status (see below) 04h DWORD caller's virtual address in FailingModules structure 08h DWORD unused 0Ch WORD unused Format of request block for GetProtocolManagerLinkage: Offset Size Description 00h WORD 04h 02h WORD returned status (see below) 04h DWORD returned dispatch point 08h DWORD unused 0Ch WORD returned protocol manager DS Note: the dispatch point may be called as follows instead of using this IOCTL STACK: WORD protocol manager DS DWORD pointer to request block Return: AX = returned status STACK popped Format of request block for GetProtocolIniPath: Offset Size Description 00h WORD 05h 02h WORD returned status (see below) 04h DWORD pointer to a buffer for the ASCIZ pathname of PROTOCOL.INI 08h DWORD unused 0Ch WORD buffer length Format of request block for RegisterProtocolManagerInfo: Offset Size Description 00h WORD 06h 02h WORD returned status (see below) 04h DWORD pointer to structure containing parsed user config file 08h DWORD unused 0Ch WORD length of structure Format of request block for InitAndRegister: Offset Size Description 00h WORD 07h 02h WORD returned status (see below) 04h DWORD unused 08h DWORD poitner to ASCIZ name of the module to be prebind initialized 0Ch WORD unused Format of request block for UnbindAndStop: Offset Size Description 00h WORD 08h 02h WORD returned status (see below) 04h DWORD failing modules as for BindAndStart 08h DWORD if not 0000h:0000h, pointer to ASCIZ name of module to unbind if 0000h:0000h, terminate a set of previously dynamically bound protocol modules 0Ch WORD unused Format of request block for BindStatus: Offset Size Description 00h WORD 09h 02h WORD returned status (see below) 04h DWORD must be 0000h:0000h on return, points to root tree 08h DWORD 0000h:0000h 0Ch WORD unused under DOS Format of request block for RegisterStatus: Offset Size Description 00h WORD 0Ah 02h WORD returned status (0000h, 0008h, 002Ch) (see below) 04h DWORD 0000h:0000h 08h DWORD pointer to 16-byte ASCIZ module name 0Ch WORD 0000h Note: not supported by the 10NET v5.0 PROTMAN$ driver Values of status code: 0000h success 0001h wait for release--protocol has retained control of the data buffer 0002h request queued 0003h frame not recognized 0004h frame rejected 0005h frame should be forwarded 0006h out of resource 0007h invalid parameter 0008h invalid function 0009h not supported 000Ah hardware error 000Bh transmit error 000Ch unrecognized destination 000Dh buffer too small 0020h already started 0021h binding incomplete 0022h driver not initialized 0023h hardware not found 0024h hardware failure 0025h configuration failure 0026h interrupt conflict 0027h MAC incompatible 0028h initialization failed 0029h no binding 002Ah network may be disconnected 002Bh incompatible OS version 002Ch already registered 002Dh path not found 002Eh insufficient memory 002Fh info not found 00FFh general failure F000h-FFFFh reserved for vendor-specific codes, treated as general failure Format of common characteristics table: Offset Size Description 00h WORD size of table in bytes 02h BYTE NDIS major version 03h BYTE NDIS minor version 04h WORD reserved 06h BYTE module major version 07h BYTE module minor version 08h DWORD module function flag bits bit 0: binding at upper boundary supported bit 1: binding at lower boundary supported bit 2: dynamically bound bits 3-31 reserved, must be 0 0Ch 16 BYTEs ASCIZ module name 1Ch BYTE upper boundary protocol level 01h Media Access Control 02h Data link 03h network 04h transport 05h session FFh not specified 1Dh BYTE upper boundary interface type for MACs: 1 = MAC for data links and transports: to be defined for session: 1 = NCB any level: 0 = private (ISV-defined) 1Eh BYTE lower boundary protocol level 00h physical 01h Media Access Control 02h Data link 03h network 04h transport 05h session FFh not specified 1Fh BYTE lower boundary interface type same as offset 1Dh 20h WORD module ID filled in by protocol manager 22h WORD module DS 24h DWORD system request entry point 28h DWORD pointer to service-specific characteristics 0000h:0000h if none 2Ch DWORD pointer to service-specific status 0000h:0000h if none 30h DWORD pointer to upper dispatch table (see below) 0000h:0000h if none 34h DWORD pointer to lower dispatch table (see below) 0000h:0000h if none 38h DWORD reserved, must be 0 3Ch DWORD reserved, must be 0 Note: for compatibility with NDIS 1.x.x, a major version of 00h is interpreted as 01h Format of MAC Service-Specific Characteristics Table: Offset Size Description 00h WORD length of table in bytes 02h 16 BYTEs ASCIZ MAC type name, "802.3", "802.4", "802.5", "802.6", "DIX", "DIX+802.3", "APPLETALK", "ARCNET", "FDDI", "SDLC", "BSC", "HDLC", or "ISDN" 12h WORD length of station addresses in bytes 14h 16 BYTEs permanent station address 24h 16 BYTEs current station address 34h DWORD current functional adapter address (00000000h if none) 38h DWORD pointer to multicast address list 3Ch DWORD link speed in bits/sec 40h DWORD service flags (see below) 44h WORD maximum frame size which may be both sent and received 46h DWORD total transmit buffer capacity in bytes 4Ah WORD transmit buffer allocation block size in bytes 4Ch DWORD total receive buffer capacity in bytes 50h WORD receive buffer allocation block size in bytes 52h 3 BYTEs IEEE vendor code 55h BYTE vendor adapter code 56h DWORD pointer to ASCIZ vendor adapter description 5Ah WORD IRQ used by adapter 5Ch WORD transmit queue depth 5Eh WORD maximum supported number of data blocks in buffer descriptors 60h N BYTEs vendor-specific info Bitfields for service flags: bit 0 supports broadcast bit 1 supports multicast bit 2 supports functional/group addressing bit 3 supports promiscuous mode bit 4 station address software settable bit 5 statistics always current bit 6 supports InitiateDiagnostics bit 7 supports loopback bit 8 MAC does primarily ReceiveChain indications instead of ReceiveLookahead indications bit 9 supports IBM source routing bit 10 supports MAC reset bit 11 supports Open/Close adapter bit 12 supports interrupt request bit 13 supports source routing bridge bit 14 supports GDT virtual addresses (OS/2 version) bit 15 multiple TransferDatas allowed durign a single indication bit 16 MAC normally sets FrameSize = 0 in ReceiveLookahead bit 17-31 reserved, must be 0 Format of NetBIOS Service-Specific Characteristics Table Offset Size Description 00h WORD length of table in bytes 02h 16 BYTEs ASCIZ type name of NetBIOS module 12h WORD NetBIOS module code 14h N BYTEs vendor-specific info Format of MAC Service-Specific Status Table: Offset Size Description 00h WORD length of table in bytes 02h DWORD seconds since 0:00 1/1/70 when diagnostics last run (FFFFFFFFh = never) 06h DWORD MAC status bits bits 0-2: operational status 000 hardware not installed 001 hardware failed startup diagnostics 010 hardware configuration problem 011 hardware fault 100 operating marginally due to soft faults 101 reserved 110 reserved 111 hardware fully operational bit 3: MAC bound bit 4: MAC open bit 5: diagnostics in progress bits 6-31: reserved 0Ah WORD current packet filter flags bit 0: directed/multicast or group/functional bit 1: broadcast bit 2: promiscuous bit 3: all source routing bits 4-15: reserved, must be zero 0Ch DWORD pointer to media-specific status table or 0000h:0000h 10h DWORD seconds past 0:00 1/1/70 of last ClearStatistics 14h DWORD total frames received (FFFFFFFFh = not counted) 18h DWORD frames with CRC error (FFFFFFFFh = not counted) 1Ch DWORD total bytes received (FFFFFFFFh = not counted) 20h DWORD frames discarded--no buffer space (FFFFFFFFh = not counted) 24h DWORD multicast frames received (FFFFFFFFh = not counted) 28h DWORD broadcast frames received (FFFFFFFFh = not counted) 2Ch DWORD frames with errors (FFFFFFFFh = not counted) 30h DWORD overly large frames (FFFFFFFFh = not counted) 34h DWORD frames less than minimum size (FFFFFFFFh = not counted) 38h DWORD multicast bytes received (FFFFFFFFh = not counted) 3Ch DWORD broadcast bytes received (FFFFFFFFh = not counted) 40h DWORD frames discarded--hardware error (FFFFFFFFh = not counted) 44h DWORD total frames transmitted (FFFFFFFFh = not counted) 48h DWORD total bytes transmitted (FFFFFFFFh = not counted) 4Ch DWORD multicast frames transmitted (FFFFFFFFh = not counted) 50h DWORD broadcast frames transmitted (FFFFFFFFh = not counted) 54h DWORD broadcast bytes transmitted (FFFFFFFFh = not counted) 58h DWORD multicast bytes transmitted (FFFFFFFFh = not counted) 5Ch DWORD frames not transmitted--timeout (FFFFFFFFh = not counted) 60h DWORD frames not transmitted--hardware error (FFFFFFFFh = not countd) 64h N BYTEs vendor-specific info --------I-214402----------------------------- INT 21 U - IBM SYSTEM 36/38 WORKSTATION EMULATION - VDI.SYS - GET ??? AX = 4402h BX = handle for character device "GDMS" CX = number of bytes to read (>= 4) DS:DX -> buffer (see below) Return: CF set on error AX = error code (see AH=59h) CF clear if successful AX = number of bytes read Format of returned data: Offset Size Description 00h 4 BYTEs ??? 04h DWORD pointer to ??? 08h 4 BYTEs ??? --------m-214402----------------------------- INT 21 U - LASTBYTE.SYS v1.19 - IOCTL - GET ??? TABLE AX = 4402h BX = handle for device "LA$TBYTE" CX = 0004h DS:DX -> DWORD to hold address of 39-byte table of ??? Return: CF set on error AX = error code (see AH=59h) CF clear if successful AX = number of bytes read Note: LASTBYTE.SYS is part of "The Last Byte" by Key Software Products SeeAlso: AX=4402h"HIGHUMM" --------m-214402----------------------------- INT 21 - HIGHUMM.SYS v1.17+ - IOCTL - GET API ADDRESS AX = 4402h BX = handle for device "KSP$UMM" CX = 0004h DS:DX -> DWORD to hold entry point Return: CF set on error AX = error code (see AH=59h) CF clear if successful AX = number of bytes read Note: HIGHUMM.SYS is part of "The Last Byte" by Key Software Products SeeAlso: AX=4402h"LASTBYTE" Call HIGHUMM.SYS entry point with: AH = 00h allocate UMB (same as XMS function 10h) (see INT 2F/AX=4310h) DX = size in paragraphs Return: BX = segment number (if successful) DX = size of requested block/size of largest block AH = 01h deallocate UMB (same as XMS func 11h) (see INT 2F/AX=4310h) DX = segment number of UMB AH = 02h request a bank-switched memory block DX = size in paragraphs Return: BX = segment number (if successful) DX = size of requested block/size of largest block AH = 03h release a bank-switched memory block DX = segment number AH = 04h transfer data to/from high memory DS:SI -> source ES:DI -> destination CX = length in bytes Note: enables bank-switched memory, does the copy, then disables bank-switched memory AH = 05h get a word from bank-switched memory ES:DI -> word to read Return: DX = word AH = 06h put a word to bank-switched memory ES:DI -> word to write DX = word AH = 07h put a byte to bank-switched memory ES:DI -> byte to write DL = byte AH = 08h enable bank-switched memory DS:SI -> 6-byte status save area AH = 09h disable bank-switched memory DS:SI -> 6-byte save area from enable call (AH=08h) AH = 0Ah assign name to UMB or high bank-switched block DX = segment number DS:SI -> 8-byte blank-padded name AH = 0Bh locate UMB block by name DS:SI -> 8-byte blank-padded name Return: BX = segment number (if successful) DX = size of block AH = 0Ch locate bank-switched block by name DS:SI -> 8-byte blank-padded name Return: BX = segment number (if successful) DX = size of block Return: AX = status code 0001h successful 0000h failed BL = error code 80h not implemented B0h insufficient memory, smaller block available B1h insufficient memory, no blocks available B2h invalid segment number Note: only functions 00h and 01h are always available; the remaining functions are only enabled if the proper commandline switch is given --------c-214402----------------------------- INT 21 - SMARTDRV.SYS - IOCTL - GET CACHE STATUS AX = 4402h BX = file handle for device "SMARTAAR" CX = number of bytes to read (min 28h) DS:DX -> buffer for status record (see below) Return: CF clear if successful AX = number of bytes actually read CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4403h"SMARTDRV",INT 2F/AX=4A10h/BX=0000h Format of SMARTDRV status record: Offset Size Description 00h BYTE write-through flag (always 01h) 01h BYTE writes should be buffered (always 00h) 02h BYTE cache enabled if 01h 03h BYTE driver type (01h extended memory, 02h expanded) 04h WORD clock ticks between cache flushes (currently unused) 06h BYTE cache contains locked tracks if nonzero 07h BYTE flush cache on INT 19 reboot if nonzero 08h BYTE cache full track writes if nonzero 09h BYTE double buffering (for VDS) state (00h off, 01h on, 02h dynamic) 0Ah DWORD original INT 13 vector 0Eh BYTE minor version number 0Fh BYTE major version number 10h WORD unused 12h WORD sectors read \ 14h WORD sectors already in cache > may be scaled rather than 16h WORD sectors already in track buffer / absolute counts 18h BYTE cache hit rate in percent 19h BYTE track buffer hit rate in percent 1Ah WORD total tracks in cache 1Ch WORD number of tracks in use 1Eh WORD number of locked tracks 20h WORD number of dirty tracks 22h WORD current cache size in 16K pages 24h WORD original (maximum) cache size in 16K pages 26h WORD minimum cache size in 16K pages 28h DWORD pointer to byte flag to increment for locking cache contents --------d-214402----------------------------- INT 21 - CD-ROM device driver - IOCTL INPUT AX = 4402h BX = file handle referencing character device for CD-ROM driver CX = number of bytes to read DS:DX -> control block (see below) Return: CF clear if successful AX = number of bytes actually read CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: the data returned depends on the first byte of the control block; the remainder of the control block is filled by the driver SeeAlso: AX=4403h"CD-ROM",INT 2F/AX=0802h Format of control block: Offset Size Description 00h BYTE data being requested 00h device driver header address 01h drive head location 02h reserved 03h error statistics 04h audio channel info 05h raw drive bytes (uninterpreted and device-specific) 06h device status 07h sector size 08h volume size 09h media change status 0Ah audio disk info 0Bh audio track info 0Ch audio Q-Channel info 0Dh audio sub-channel info 0Eh UPC code ---function 00h--- 01h DWORD device driver header address (see also AH=52h) ---function 01h--- 01h BYTE addressing mode 00h HSG 01h Red Book 02h DWORD current location of drive's head logical sector number in HSG mode frame/second/minute/unused in Red Book mode (HSG sector = minute * 4500 + second * 75 + frame - 150) ---function 03h--- 01h N BYTEs undefined as of 5 Aug 88 specification ---function 04h--- 01h BYTE input channel (0-3) for output channel 0 02h BYTE volume for output channel 0 03h BYTE input channel (0-3) for output channel 1 04h BYTE volume for output channel 1 05h BYTE input channel (0-3) for output channel 2 06h BYTE volume for output channel 2 07h BYTE input channel (0-3) for output channel 3 08h BYTE volume for output channel 3 Notes: output channels 0 and 1 are left and right, 2 and 3 are left prime and right prime; a volume of 00h is off the default setting is for each input channel to be assigned to the same-numbered output channel at full (FFh) volume ---function 05h--- 01h BYTE number of bytes read 02h 128 BYTEs buffer for drive bytes ---function 06h--- 01h DWORD device parameters bit 0: door open bit 1: door unlocked bit 2: supports raw reading in addition to cooked bit 3: writable bit 4: can play audio/video tracks bit 5: supports interleaving bit 6: reserved bit 7: supports prefetch requests bit 8: supports audio channel control bit 9: supports Red Book addressing in addition to HSG bit 10: audio is playing ---function 07h--- 01h BYTE read mode 00h cooked 01h raw 02h WORD sector size in bytes ---function 08h--- 01h DWORD volume size in sectors ---function 09h--- 01h BYTE media change status 00h don't know 01h media unchanged FFh media has been changed ---function 0Ah--- 01h BYTE lowest audio track number 02h BYTE highest audio track number 03h DWORD start address of lead-out track (Red Book format) --function 0Bh--- 01h BYTE track number (set by caller) 02h DWORD starting point of track (Red Book format) 06h BYTE track control info bits 15,14,12: track type (notice: bits not contiguous!) 000 two audio channels, no pre-emphasis 001 two audio channels with pre-emphasis 010 data track 100 four audio channels, no pre-emphasis 101 four audio channels with pre-emphasis other reserved bit 13: digital copy permitted ---function 0Ch--- 01h BYTE CONTROL and ADR byte (as received from drive) 02h BYTE track number 03h BYTE point or index 04h BYTE minute \ 05h BYTE second > running time within track 06h BYTE frame / 07h BYTE zero 08h BYTE "AMIN" or "PMIN" \ 09h BYTE "ASEC" or "PSEC" > running time on disk 0Ah BYTE "AFRAME" or "PFRAME" / ---function 0Dh--- 01h DWORD starting frame address (Red Book format) 05h DWORD transfer address 09h DWORD number of sectors to read Note: copies 96 bytes of sub-channel info per sector into buffer ---function 0Eh--- 01h BYTE CONTROL and ADR byte 02h 7 BYTEs UPC/EAN code (13 BCD digits,low-order nybble of last byte is 0) 09h BYTE zero 0Ah BYTE "AFRAME" --------m-214402----------------------------- INT 21 U - Quarterdeck - QEMM-386 v5+ - GET API ENTRY POINT AX = 4402h BX = file handle for device "QEMM386$" CX = 0004h DS:DX -> DWORD buffer for API entry point Return: CF clear if successful buffer filled (see INT 67/AH=3Fh for entry point parameters) CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4402h"HOOKROM",INT 2F/AX=D201h/BX=5145h,INT 67/AH=3Fh --------m-214402----------------------------- INT 21 U - Quarterdeck - QEMM-386 v6+ - GET EMM IMPORT STRUCTURE ADDRESS AX = 4402h BX = file handle for device "EMMXXXX0" CX = 0006h (size of buffer in bytes) DS:DX -> buffer for import structure address (see below) first byte must be 01h on entry Return: CF clear if successful buffer filled (see INT 67/AH=3Fh function 1B00h) CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: this call always returns an error if Windows3 support has been disabled with the NW3 switch to QEMM386.SYS SeeAlso: INT 2F/AX=D201h/BX=5145h,INT 67/AH=3Fh Format of import structure address: Offset Size Description 00h DWORD physical address of EMM import structure 04h BYTE major version 05h BYTE minor version --------Q-214402----------------------------- INT 21 U - Quarterdeck - HOOKROM.SYS - GET HOOKED VECTOR TABLE AX = 4402h BX = file handle for device "HOOKROM$" CX = 0004h DS:DX -> DWORD buffer for address of hooked vector table (see below) Return: CF clear if successful DS:DX buffer filled CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4402h"QEMM" Format of hooked vector table entry: Offset Size Description 00h 5 BYTEs FAR jump to actual interrupt handler (end of table if first byte is not EAh) 05h BYTE interrupt vector number --------m-214402----------------------------- INT 21 U - Microsoft EMM386.EXE v4.45 - GET MEMORY MANAGER INFORMATION AX = 4402h BX = file handle for device "EMMXXXX0" CX = size of buffer in bytes (varies, see below) DS:DX -> buffer for returned data (see below) first byte must be set on entry to indicate desired data Return: CF clear if successful buffer filled CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: an error is returned if the number of bytes to be read does not match the number of bytes returned for the specified data item SeeAlso: INT 67/AX=FFA5h Format of data buffer: Offset Size Description 00h BYTE (call) function 00h get ??? 01h get EMM import structure??? 02h get ??? 03h get ??? 04h get ??? ---function 00h--- 00h WORD ??? (0025h) 02h DWORD API entry point (see INT 67/AX=FFA5h) ---function 01h--- 00h DWORD physical address of EMM import structure??? 04h BYTE major version??? 05h BYTE minor version??? ---function 02h--- 00h WORD ??? ---function 03h--- 00h WORD ??? 02h WORD ??? ---function 04h--- 00h WORD ??? 02h WORD number of paragraphs of ??? 04h WORD ??? --------d-214402----------------------------- INT 21 - Advanced SCSI Programming Interface (ASPI) - INTERFACE AX = 4402h BX = file handle for device "SCSIMGR$" CX = 0004h DS:DX -> buffer for function address Return: CF clear if successful AX = 0004h CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: the function address is called with the address of a SCSI Request Block on the stack and the caller must clean up the stack SeeAlso: AX=440Ch"ASPITAPE",INT 11/AH=FFh"WD7000" Format of SCSI Request Block (64 bytes): Offset Size Description 00h BYTE request number 00h "HA_INQ" host adapter inquiry 01h "GET_TYPE" get device type 02h "EXEC_SIO" execute SCSI I/O 03h "ABORT_SRB" abort SRB 04h "RESET_DEV" reset SCSI device 05h "SET_HAPRMS" set host adapter parameters 01h BYTE request status 00h not done yet 02h aborted 04h SCSI I/O error 80h invalid 81h no adapter 82h no device attached else status 02h BYTE host adapter ID 03h BYTE request flags bit 3: ??? 04h DWORD reserved ---request 00h--- 08h BYTE (returned) number of host adapters 09h BYTE (returned) target adapter ID 0Ah 16 BYTEs (returned) manager ID 1Ah 16 BYTEs (returned) adapter ID 2Ah 16 BYTEs (returned) parameters ---request 01h--- 08h BYTE target ID 09h BYTE logical unit number 0Ah BYTE (returned) device type 01h streamer ---request 02h--- 08h BYTE target ID 09h BYTE logical unit number 0Ah DWORD data allocation length 0Eh BYTE sense allocation length 0Fh DWORD data buffer pointer 13h DWORD next request pointer (for linking) 17h BYTE CDB length 18h BYTE (returned) host adapter status 11h select timeout 12h data overrun 13h bus error 14h bus failure 19h BYTE (returned) target status 02h sense data stored in SRB 08h target busy 18h reservation error 1Ah DWORD post routine address 1Eh WORD real mode Post DS 20h DWORD SRB pointer 24h WORD reserved 26h DWORD SRB physical address 2Ah 22 BYTEs SCSIMGR$ workspace 40h N BYTEs CCB (20-24 bytes) ---request 04h--- 08h BYTE target ID 09h BYTE logical unit number 0Ah 14 BYTEs reserved 18h BYTE (returned) host adapter status (see above) 19h BYTE (returned) target status (see above) 1Ah DWORD post routine address 1Eh 34 BYTEs workspace Format of CCB: Offset Size Description 00h BYTE command code 01h rewind 05h get block size limits 08h read 0Ah write 10h write file marks 11h SCSI Space (set position?) 12h SCSI Inquire 19h erase 1Bh load/unload media 01h BYTE flags bits 4-0: vary by function bits 7-5: logical unit number 02h BYTE "adr_1" 03h BYTE "adr_0" 04h BYTE length 05h BYTE control ... 06h/0Ah 14 BYTEs buffer for sense data --------m-214402----------------------------- INT 21 U - Qualitas 386MAX v6.00+ - IOCTL INPUT - GET STATE AX = 4402h BX = file handle for device "386MAX$$" CX = 005Ah DS:DX -> version byte followed by 386MAX state buffer (see below) version byte must be 03h for 386MAX v6.01 Return: CF clear if successful buffer at DS:DX+1 filled AX = number of bytes actually copied CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Notes: if the value given in CX is less than 5Ah, only a partial state record will be returned the state is 40h bytes for 386MAX (actually ASTEMM) v2.20 ("386MAX$$" did not exist yet, use "QMMXXXX0" and then "EMMXXXX0" instead) and 56h bytes for v5.11. to invoke 386MAX API functions, push DX onto the stack, load DX with the word at offset 25h in the returned state, load all other registers as needed for the desired function, and execute an OUT DX,AL or OUT DX,AX; DX will be set to the pushed value on return if it is not otherwise modified by the API function. For safety, in case a function is not supported or 386MAX is not present, SP should be saved and restored around the API call. Windows 3.1 Standard mode, LAN Manager, and Windows for Workgroups all use the 386MAX API; LAN Manager and Windows for Workgroups reportedly make some calls incorrectly SeeAlso: AX=4403h"386MAX",INT 67/AH=3Fh Format of 386MAX v6.01 state: Offset Size Description 00h 6 BYTEs signature "386MAX" 06h 4 BYTEs version string "N;NN" (i.e. "6;01" for v6.01) 0Ah WORD segment of low-memory portion of 386MAX.SYS 0Ch 2 BYTEs ??? 0Eh WORD segment of ??? memory block or 0000h 10h WORD bit flags bit 1: ??? bit 2: ??? bit 3: ??? (cleared by calling INT 67 functions) bit 4: high RAM present??? bit 5: ??? bit 6: 386MAX active??? bit 7: 386MAX is providing EMS services bit 8: ??? bit 9: ??? (see INT 15/AX=2402h) bit 10: ??? bit 11: ??? bit 12: ??? bit 13: QPMS has been used bit 14: ??? bit 15: ??? 12h WORD starting address of video memory in K 14h 2 BYTEs ??? 16h WORD total high DOS memory in KB 18h 2 BYTEs ??? 1Ah WORD available shared memory in KB 1Ch WORD KBytes extended memory used by 386MAX 1Eh 2 BYTEs ??? 20h WORD total extended memory in KB 22h WORD IO port to write (OUT DX,AL) to invoke 386MAX INT 15 functions 24h WORD IO port to write (OUT DX,AL) to invoke 386MAX API functions 26h WORD ??? 28h 2 BYTEs ??? 2Ah DWORD ??? 2Eh 4 BYTEs ??? 32h WORD system configuration??? flags bit 1: ROM compressed??? bit 3: ??? bit 5: 386MAX loaded into high memory bit 11: PC/XT (thus only single 8259 interrupt controller present, DMA only in 1st megabyte, etc) 34h WORD ??? bit flags 36h 4 BYTEs ??? 3Ah WORD segment of first MCB in high memory chain??? 3Ch WORD flags bit 2: no DPMI services bit 11: don't backfill holes in video memory area bit 12: don't backfill below video memory??? 3Eh WORD flags bit 7: ??? 40h WORD flags bit 0: Windows3 support enabled bit 8: ??? 42h WORD segment of first 386MAX control block??? (see below) 44h WORD amount of memory to report available on INT 15/AH=88h 46h 4 BYTEs ??? 4Ah WORD ??? 4Ch 2 BYTEs ??? 4Eh WORD ??? 50h WORD bit flags bit 12: ??? 52h DWORD old INT 21h 56h DWORD pointer to 386MAX's EMS (INT 67h) handler Format of 386MAX control block: Offset Size Description 00h WORD segment of next block (FFFFh if last) 02h WORD segment of previous block (FFFFh if first) 04h 12 BYTEs filename 10h WORD resident size in paragraphs 12h WORD environment size??? 14h WORD real prsent environment size + 1 (0000h if ENVSAVE used) 16h 2 BYTEs ??? 18h DWORD initial size or SIZE=n in 386LOAD commandline 1Ch DWORD SIZE=-1 ??? 20h DWORD SIZE= ??? 24h BYTE PRGREG= if specified, else FFh 25h BYTE ENVREG= if specified, else FFh 26h BYTE FlexFrame (00h not present, 01h present) 27h 3 BYTEs ??? 2Ah BYTE GROUP= or 00h if not present 2Bh BYTE ??? 2Ch WORD PSP Format of high memory info record: Offset Size Description 00h WORD segment address of memory region 02h WORD size of memory region in paragraphs 04h BYTE type or flags??? 00h if locked out 02h if EMS page frame 04h if high RAM 42h if ROM 05h BYTE ??? Format of ROM shadowing record: Offset Size Description 00h WORD segment of ROM??? 02h WORD segment of ROM??? 04h 2 BYTEs ??? 06h WORD size of shadowed ROM in paragraphs 08h 4 BYTEs ??? Values for memory type: 00h unused by EMS 01h DOS 04h page frame overlapping ROM??? 80h high memory 84h page frame??? 87h video ROM??? Note: the type may be 00h (unused) if the 16K page is split among different uses (such as ROM and high RAM) Call 386MAX API (via OUT DX,AL) with: STACK: WORD value for DX AH = 01h get high memory information ES:DI -> buffer for array of high memory info records (see above) Return: CX = number of records placed in buffer AH = 02h get shadowed ROM info??? ES:DI -> buffer for array of ROM shadowing records (see above) Return: CX = number of records placed in buffer AH = 03h get 386MAX state ES:DI -> 90-byte buffer for state (see above) Return: AH = 00h (successful) buffer filled Note: unlike INT 21/AX=4402h"386MAX", this function omits the first byte specifying the state buffer version AH = 04h get memory types??? ES:DI -> buffer for memory type info (array of bytes, one per 16K page) (see above) Return: CX = number of bytes placed in buffer AH = 05h get ??? AL = subfunction 00h invoke INT 15/AX=2401h first 01h don't invoke INT 15/AX=2401h first CX = number of bytes to copy (0000h for default) SI = ??? ES:DI -> buffer for ??? Return: CX = number of bytes actually copied ??? AH = 06h get memory speed info ES:DI -> buffer for memory speed records (see below) Return: AH = 00h (successful) CX = number of bytes placed in buffer Note: this function can take over a second to execute AH = 07h ??? ??? Return: ??? AH = 08h ??? AL = ??? (00h or nonzero) AH = 09h toggle ??? flags BX = bitmask of bits of ??? flags (word at state+10h) to toggle Return: AH = 00h (successful) Note: invokes INT 15/AX=2401h first AH = 0Ah toggle ??? flags BX = bitmask of bits of ??? (word at state+32h) to toggle Return: AH = 00h (successful) Notes: invokes INT 15/AX=2401h first does ??? if bit 3 on after specified bits are toggled AH = 0Bh toggle ??? flags BX = bitmask of bits of ??? (word at state+34h) to toggle Return: AH = 00h (successful) Note: invokes INT 15/AX=2401h first AH = 0Ch toggle ??? flags BX = bitmask of bits of ??? (word at state+40h) to toggle Return: AH = 00h (successful) Note: invokes INT 15/AX=2401h first AH = 0Dh specify 386MAX high-memory location BX = segment address of high-memory real-mode portion of 386MAX ??? Return: AH = status (00h successful) ??? AH = 0Eh CRT controller register virtualization AL = subfunction 00h allow access to CRTC I/O ports 03B4h/03B5h, 03D4h/03D5h 01h trap accesses to CRTC I/O ports AH = 0Fh reboot system Return: never AH = 11h get high memory information ES:DI -> 96-byte buffer for high memory info Return: AH = 00h (successful) ES:DI buffer filled Notes: each byte in buffer contains bit flags for a 4K page in the A000h-FFFFh region bit 0: ??? bit 1: physical address same as linear address bit 2: EMS page frame bit 6: ??? this function can take over a second to execute AH = 12h ??? AL = subfunction 00h ??? 01h ??? ??? Return: AH = 00h (successful) if AL=00h or 01h AH = 8Fh otherwise AH = 13h page protection??? AL = subfunction 00h set all ??? 4K pages to read-only??? 01h set all ??? 4K pages to read-write??? ??? Return: AH = 00h (successful) if AL=00h or 01h AH = 8Fh otherwise AH = 15h ??? ??? Return: ??? AH = 16h get 386MAX memory usage screen ES:DI -> buffer for memory info display CX = size of buffer in bytes Return: ES:DI buffer filled with '$'-terminated string (if large enough to hold entire usage screen) AH = 17h Windows 3 startup/termination AL = subfunction 00h Windows3 initializing DX (on stack) = Windows startup flags DI = Windows version number (major in upper byte) ES:BX = 0000h:0000h DS:SI = 0000h:0000h Return: CX = 0000h if OK for Windows to load <> 0 if Windows should not load ES:BX -> startup info structure DS:SI -> Virtual86 mode enable/disable callback 01h Windows3 terminating ES:BX -> ??? DX (on stack) = Windows exit flags Return: ??? AH = 18h QPMS (Qualitas Protected Memory Services) AL = subfunction 00h get QPMS configuration Return: BX = starting segment of QPMS memory window CX = number of 4K pages reserved for QPMS??? DX = number of 4K pages in QPMS window??? 01h map QPMS memory page??? BX = 4K page number within memory reserved for QPMS??? CL = 4K page number within QPMS memory window??? 02h mark all QPMS memory read-only 03h mark all QPMS memory read-write Return: AH = status (00h,8Ah,8Bh,8Fh) AH = 19h get linear address for physical address EDX = physical address (low word on stack) Return: AH = status 00h successful EDX = linear address at which physical address may be accessed 8Bh physical address currently not addressable Note: calls INT 15/AX=2401h first AH = 1Ah set page table entry??? EDX = new page table entry??? (low word on stack) ESI = linear address of page??? Return: AH = status (00h,8Bh) Note: calls INT 15/AX=2401h first AH = 1Bh get ??? Return: AH = status BX = ??? CX = ??? EDX = physical address of ??? AH = 1Ch get original interrupt vector AL = interrupt vector (00h-7Fh) Return: AH = 00h (successful) EDX = original vector before 386MAX loaded (segment in high word, offset in low word) Note: no range checking is performed; requests for INTs 80h- FFh will return random values AH = 1Dh display string??? SI = ??? Return: AH = 00h (successful) ??? AH = 1Eh ??? ES:DI -> ??? ??? Return: ??? AH = 1Fh ??? ??? Return: AX = 0000h if successful BX = ??? (0001h for 386MAX v6.01) CL = ??? DL = state buffer size??? (5Ah for 386MAX v6.01) DH = ??? (00h for 386MAX v6.01) SI = ??? ES???:DI -> ??? AH = 40h-5Dh EMS services (see INT 67/AH=40h etc) AH = DEh VCPI services (see INT 67/AX=DE00h etc) Return: AH = status (as for EMS INT 67 calls) 00h successful 80h internal error 81h hardware malfunction 83h invalid handle 84h undefined function 8Ah invalid logical page nuber 8Bh illegal physical page number 8Fh undefined subfunction A4h access denied etc. STACK popped (value placed in DX if no specific return value for DX) Format of memory speed record: Offset Size Description 00h DWORD page table entry for 4K page 04h WORD number of microticks (840ns units) required for REP LODSD of entire 4K page --------V-214402----------------------------- INT 21 - PGS1600.DEV - IOCTL - GET CONFIGURATION INFO AX = 4402h BX = file handle for device "PGS1600$" CX = 0018h (size of buffer) DS:DX -> configuration buffer (see below) Return: CF clear if successful buffer filled AX = number of bytes actually copied CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Program: PGS1600.DEV is a device driver for the Cornerstone Technology PG1600 display adapter, which provides a 1600x1200 monochrome display as well as one of two emulations, MDA or CGA. SeeAlso: AX=4403h"PGS1600" Format of configuration information: Offset Size Description 00h WORD version (high byte = major, low byte = minor) 02h WORD board initialisation mode 04h WORD board I/O address 03D0h CGA emulation 03B0h MDA emulation 0390h no emulation 0350h no emulation, alternate 06h WORD emulation buffer segment B800h CGA emulation B000h MDA emulation 0000h no emulation 08h WORD PG1600 graphics buffer segment 0Ah WORD number of bytes between consecutive graphic rows 0Ch WORD horizontal pixel size 0Eh WORD vertical pixel size 10h WORD horizontal dots per inch 12h WORD vertical dots per inch 14h WORD graphics buffer bits per pixel 16h WORD monitor bits per pixel --------N-214402----------------------------- INT 21 - PC/TCP IPCUST.SYS - RESET CONFIGURATION DATA READ POINTER AX = 4402h BX = file handle referencing device "$IPCUST" CX, DS:DX ignored Return: CF clear if successful AX destroyed CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Notes: there are a total of 378h bytes of configuration data for IPCUST.SYS version 2.05. If less than the entire data is read or written, the next read/write continues where the previous one ended; this call and AX=4403h both reset the location at which the next operation starts to zero v2.1+ uses a new configuration method, but allows the installation of IPCUST.SYS for backward compatibility with other software which must read the PC/TCP configuration SeeAlso: AH=3Fh"IPCUST",AH=40h"IPCUST",AX=4403h"IPCUST" --------N-214402----------------------------- INT 21 - WORKGRP.SYS - GET API ENTRY POINT AX = 4402h BX = file handle for device "NET$HLP$" CX = 0008h DS:DX -> buffer for entry point record Return: CF clear if successful AX = number of bytes actually read CF set on error AX = error code Program: WORKGRP.SYS is distributed with MS-DOS 6.0 to permit communication with PCs running Windows for Workgroups or LAN Manager SeeAlso: AH=3Fh"WORKGRP.SYS" Format of entry point record: Offset Size Description 00h WORD 3633h \ signature??? 02h WORD EF6Fh / 04h DWORD address of entry point Note: first four bytes of buffer must be 6Fh E9h 33h 36h on entry when using IOCTL rather than READ to get the entry point record Call WORKGRP entry point with: STACK: WORD function number (0000h-0009h) Return: STACK unchanged Call WORKGRP function 00h with: STACK: WORD 0000h (function "get ???") Return: DX:AX -> data table Call WORKGRP function 01h with: STACK: WORD 0001h (function "hook ???") Return: STACK: DWORD pointer to ??? WORD 0001h (function number) Call WORKGRP function 02h with: STACK: WORD 0002h (function "unhook ???") ??? Return: ??? Call WORKGRP function 03h with: STACK: WORD 0003h (function "reenable printer port") WORD LPT port number Return: ??? Call WORKGRP function 04h with: STACK: WORD 0004h (function "disable printer port") WORD LPT port number Return: ??? Call WORKGRP function 05h with: STACK: WORD 0005h (function "???") ??? Return: ??? Call WORKGRP function 06h with: STACK: WORD 0006h (function "???") Return: STACK unchanged AX = 0000h DX = 0000h Call WORKGRP functions 07h-09h with: STACK: WORD 0007h-0009h (NOP functions) Return: STACK unchanged AX = 0001h DX = 0000h --------N-214402----------------------------- INT 21 - 10NET v5.0 - 10BEUI.DOS - API AX = 4402h BX = file handle referencing device "10BEUI$" DS:DX -> parameter record (see below) CX ignored Return: CF clear if successful AX destroyed CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4402h"10MEMMGR",INT 6F/AH=00h"10NET" Format of parameter record: Offset Size Description 00h WORD 000Ah (function number???) 02h WORD ??? 04h DWORD pointer to buffer for ??? 08h 4 BYTEs ??? 0Ch WORD transfer size --------N-214402----------------------------- INT 21 - 10NET v5.0 - 10MEMMGR.SYS - API AX = 4402h BX = file handle referencing device "MEMMGR0$" DS:DX -> 6-byte buffer for interface info (see below) CX ignored Return: CF clear if successful AX destroyed CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4402h"10BEUI",INT 6F/AH=00h"10NET" Format of interface info: Offset Size Description 00h DWORD address of entry point (see below) 04h WORD version (0500h for v5.00) Call entry point with: AL = 01h ??? BX = ??? Return: CF clear if successful CF set on error AX = error code AL = 02h ??? ??? AL = 03h ??? ??? AL = 04h set/restore memory allocation strategy BX = subfunction 0000h set strategy 0001h restore strategy Return: CF clear if successful CF set on error (if function disabled) various registers destroyed AL = other Return: CF set AX = 0000h BL = 01h --------D-214403----------------------------- INT 21 - DOS 2+ - IOCTL - WRITE TO CHARACTER DEVICE CONTROL CHANNEL AX = 4403h BX = file handle referencing character device CX = number of bytes to write DS:DX -> data to write Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Notes: format of data is driver-specific (see below for some specific cases) if the file handle refers to "4DOSSTAK", the 4DOS (v2.x-3.03) KEYSTACK.SYS driver will push the specified characters on the keyboard stack; similarly for "NDOSSTAK", the NDOS KEYSTACK.SYS driver will push the characters onto the keyboard stack SeeAlso: AX=4400h,AX=4402h,AX=4405h,INT 2F/AX=122Bh,INT 2F/AX=D44Dh SeeAlso: INT 2F/AX=D44Fh --------c-214403----------------------------- INT 21 - SMARTDRV.SYS - IOCTL - CACHE CONTROL AX = 4403h BX = handle for device "SMARTAAR" CX = number of bytes to write DS:DX -> SMARTDRV control block (see below) Return: CF clear if successful AX = number of bytes actually written = 0000h if control block too small for given command CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4402h"SMARTDRV",INT 2F/AX=4A10h/BX=0000h Format of SMARTDRV control block: Offset Size Description 00h BYTE function code 00h flush cache 01h flush and discard cache 02h disable caching (flushes and discards cache first) 03h enable caching 04h control write caching 05h set flushing tick count 06h lock cache contents 07h unlock cache contents 08h set flush-on-reboot flag 09h unused 0Ah control full-track caching 0Bh reduce cache size 0Ch increase cache size 0Dh set INT 13 chain address ---function 04h--- 01h BYTE write caching control action 00h turn off write-through 01h turn on write-through 02h turn off write buffering (also flushes cache) 03h turn on write buffering (also flushes cache) ---function 05h--- 01h WORD number of timer ticks between cache flushes ---function 08h--- 01h BYTE new flush-on-reboot flag (00h off, 01h on) ---function 0Ah--- 01h BYTE full-track writes are 00h not cached 01h cached ---functions 0Bh,0Ch--- 01h WORD number of 16K pages by which to increase/reduce cache size ---function 0Dh--- 01h DWORD new address to which to chain on INT 13 Note: the previous address is not preserved --------d-214403----------------------------- INT 21 - CD-ROM device driver - IOCTL OUTPUT AX = 4403h BX = file handle referencing character device for CD-ROM driver CX = number of bytes to write DS:DX -> control block (see below) Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4402h"CD-ROM",INT 2F/AX=0802h Format of control block: Offset Size Description 00h BYTE function code 00h eject disk 01h lock/unlock door 02h reset drive 03h control audio channel 04h write device control string 05h close tray ---functions 00h,02h,05h--- no further fields ---function 01h--- 01h BYTE lock function 00h unlock door 01h lock door ---function 03h--- 01h BYTE input channel (0-3) for output channel 0 02h BYTE volume for output channel 0 03h BYTE input channel (0-3) for output channel 1 04h BYTE volume for output channel 1 05h BYTE input channel (0-3) for output channel 2 06h BYTE volume for output channel 2 07h BYTE input channel (0-3) for output channel 3 08h BYTE volume for output channel 3 Note: output channels 0 and 1 are left and right, 2 and 3 are left prime and right prime; a volume of 00h is off ---function 04h--- 01h N BYTEs bytes to send directly to the CD-ROM drive without interpretation --------d-214403----------------------------- INT 21 - Brian Antoine Seagate ST-01 SCSI.SYS - IOCTL - EXECUTE COMMANDS AX = 4403h BX = handle for device "SCSITAPE" CX = number of bytes to write DS:DX -> SCSITAPE control block (see below) Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4405h"ST-01",INT 78/AH=10h Format of SCSITAPE control block: Offset Size Description 00h WORD command type 'F' Format (argument 1 = interleave, argument 2 = format type) 'E' Erase 'R' Rewind 'L' Load 'N' No Load 'S' Space (argument 1 = count, argument 2 = type) 'M' File Mark (argument 1 = count) 'A' Reassign 02h WORD argument 1 04h WORD argument 2 06h WORD segment of command buffer 08h WORD offset of command buffer 0Ah WORD length of command buffer --------E-214403----------------------------- INT 21 U - AI Architects - OS/x86??? - API AX = 4403h BX = handle for device "AIA_OS" CX = number of bytes to write (ignored) DS:DX -> 12-byte buffer, first byte is command: 81h installation check 82h get API entry point 84h uninstall Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (01h,05h,06h,0Ch,0Dh) (see AH=59h) Notes: these functions are only available if the DOS extender was loaded as a device driver in CONFIG.SYS called by TKERNEL (a licensed version of AI Architects/Ergo OS/x86) SeeAlso: INT 2F/AX=FBA1h/BX=0081h,INT 2F/AX=FBA1h/BX=0082h Index: installation check;OS/x86|entry point;OS/x86|uninstall;OS/x86 Format of buffer on return: Offset Size Description 00h 4 BYTEs signature "IABH" ---if func 81h--- (no additional fields) ---if func 82h--- 04h DWORD pointer to API entry point (see INT 2F/AX=FBA1h/BX=0082h) ---if func 84h--- 04h WORD success indicator 06h WORD segment of ??? 08h WORD segment of ??? memory block to free if nonzero 0Ah WORD segment of ??? memory block to free if nonzero --------m-214403----------------------------- INT 21 U - Qualitas 386MAX v6.01 - SET STATE AX = 4403h BX = handle for device "386MAX$$" CX = number of bytes to copy (up to 5Ah) DS:DX -> 386MAX state buffer (see AX=4402h"386MAX") Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: the first byte of the buffer must be either 01h, 02h, or 03h (specifying the version of the state record) and the buffer must contain CX bytes AFTER the initial byte SeeAlso: AX=4402h"386MAX" --------V-214403----------------------------- INT 21 - PGS1600.DEV - IOCTL - SET CONFIGURATION??? AX = 4403h BX = file handle for device "PGS1600$" CX = 0018h (size of buffer) DS:DX -> configuration buffer (see AX=4402h"PGS1600") Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Program: PGS1600.DEV is a device driver for the Cornerstone Technology PG1600 display adapter, which provides a 1600x1200 monochrome display as well as one of two emulations, MDA or CGA. SeeAlso: AX=4402h"PGS1600" --------N-214403----------------------------- INT 21 - PC/TCP IPCUST.SYS - RESET CONFIGURATION DATA READ POINTER AX = 4403h BX = file handle referencing device "$IPCUST" CX, DS:DX ignored Return: CF clear if successful AX destroyed CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Notes: there are a total of 378h bytes of configuration data for IPCUST.SYS version 2.05. If less than the entire data is read or written, the next read/write continues where the previous one ended; this call and AX=4402h both reset the location at which the next operation starts to zero v2.1+ uses a new configuration method, but allows the installation of IPCUST.SYS for backward compatibility with other software which must read the PC/TCP configuration SeeAlso: AH=3Fh"IPCUST",AH=40h"IPCUST",AX=4402h"IPCUST" --------D-214404----------------------------- INT 21 - DOS 2+ - IOCTL - READ FROM BLOCK DEVICE CONTROL CHANNEL AX = 4404h BL = drive number (00h = default, 01h = A:, etc.) CX = number of bytes to read DS:DX -> buffer Return: CF clear if successful AX = number of bytes actually read CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: format of data is driver-specific SeeAlso: AX=4402h,AX=4405h,INT 2F/AX=122Bh --------d-214404CX0004----------------------- INT 21 - Stacker - GET DEVICE DRIVER ADDRESS AND SET VOLUME NUMBER AX = 4404h CX = 0004h BL = drive number (00h = default, 01h = A:, etc.) DS:DX -> DWORD buffer to receive device driver address Note: In addition to returning the address of the Stacker device driver, this call also sets the volume number at offset 3Eh in the device driver (see INT 25/AX=CDCDh) SeeAlso: INT 25/AX=CDCDh --------d-214404----------------------------- INT 21 - Stacker - GET STACVOL FILE SECTORS AX = 4404h BL = drive number (0 is current drive) CX = byte count (i.e., 200h = 1 sector) DS:DX -> buffer (see below) Return: Data Buffer contains the number of sectors requested from the STACVOL physical file for the drive specified. Format of stacker buffer: Offset Size Description 00h WORD 01CDh 02h WORD sector count 04h DWORD number of starting sector 08h DWORD far pointer to Data Buffer --------d-214404----------------------------- INT 21 - DUBLDISK.SYS v2.6 - GET INFO AX = 4404h BL = drive number of DoubleDisk drive (00h = default, 01h = A:, etc.) CX = number of bytes (000Ah-0014h, call ignored otherwise) DS:DX -> data record (see below) Return: CF clear if successful AX = number of bytes read CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Program: DUBLDISK.SYS is the device driver portion of DoubleDisk, a disk expander by Vertisoft Systems, Inc. Note: the installation check consists of scanning memory for the signature "FAT 2.6 byte:", which is immediately followed by a data table SeeAlso: AX=440Dh Index: installation check;DUBLDISK.SYS Format of data record: Offset Size Description 00h WORD (call) signature 4444h 02h BYTE (call) function 00h ??? 01h ??? ---function 00h--- 02h BYTE (return) ??? 03h BYTE (return) ??? ---function 01h--- 02h WORD (return) 4444h 04h WORD allocation unit size??? 06h WORD ??? 08h WORD ??? 0Ah BYTE ??? Format of signature data table: Offset Size Description 00h 5 BYTEs ??? 05h BYTE first drive number 06h BYTE number of drives 07h ??? --------d-214404----------------------------- INT 21 - DBLSPACE.BIN - IOCTL - FLUSH OR INVALIDATE INTERNAL CACHES AX = 4404h BL = drive number (00h = default, 01h = A:, etc) CX = 000Ah (size of DSPACKET structure) DS:DX -> DSPACKET structure (see below) Return: CF clear if IOCTL successful -- check DSPACKET for actual status AX = number of bytes actually transferred CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4405h"DBLSPACE",INT 2F/AX=4A11h/BX=0000h Format of DSPACKET structure: Offset Size Description 00h WORD signature 444Dh ("DM") 02h BYTE command code 46h ('F') flush internal caches 49h ('I') flush and invalidate internal caches 03h WORD result code (return) 4F4Bh ("OK") if successful, else unchanged 05h 5 BYTEs padding --------D-214405----------------------------- INT 21 - DOS 2+ - IOCTL - WRITE TO BLOCK DEVICE CONTROL CHANNEL AX = 4405h BL = drive number (00h = default, 01h = A:, etc) CX = number of bytes to write DS:DX -> data to write Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: format of data is driver-specific SeeAlso: AX=4403h,AX=4404h,INT 2F/AX=122Bh --------d-214405----------------------------- INT 21 - Brian Antoine Seagate ST-01 SCSI.SYS - IOCTL - EXECUTE COMMANDS AX = 4405h BX = drive number (00h = default, 01h = A:, etc) CX = number of bytes to write DS:DX -> SCSIDISK control block (see AX=4403h"ST-01") Return: CF clear if successful AX = number of bytes actually written CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) SeeAlso: AX=4403h"ST-01" --------d-214405----------------------------- INT 21 U - DBLSPACE.BIN - IOCTL - FLUSH OR INVALIDATE INTERNAL CACHES AX = 4405h BL = drive number (00h = default, 01h = A:, etc) CX = 000Ah (size of DSPACKET structure) DS:DX -> DSPACKET structure (see below) Return: CF clear if IOCTL successful -- check DSPACKET for actual status AX = number of bytes actually transferred CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: this call is identical to the documented AX=4404h SeeAlso: AX=4404h"DBLSPACE",INT 2F/AX=4A11h/BX=0000h Format of DSPACKET structure: Offset Size Description 00h WORD signature 444Dh ("DM") 02h BYTE command code 46h ('F') flush internal caches 49h ('I') flush and invalidate internal caches 03h WORD result code (return) 4F4Bh ("OK") if successful, else unchanged 05h 5 BYTEs padding --------D-214406----------------------------- INT 21 - DOS 2+ - IOCTL - GET INPUT STATUS AX = 4406h BX = file handle Return: CF clear if successful AL = input status 00h not ready (device) or at EOF (file) FFh ready CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: files may not register as being at EOF if positioned there by AH=42h SeeAlso: AX=4407h,INT 2F/AX=122Bh --------D-214407----------------------------- INT 21 - DOS 2+ - IOCTL - GET OUTPUT STATUS AX = 4407h BX = file handle Return: CF clear if successful AL = input status 00h not ready FFh ready CF set on error AX = error code (01h,05h,06h,0Dh) (see AH=59h) Note: for DOS 2+, files are always ready for output, even if the disk is full or no media is in the drive SeeAlso: AX=4406h,INT 2F/AX=122Bh --------D-214408----------------------------- INT 21 - DOS 3.0+ - IOCTL - CHECK IF BLOCK DEVICE REMOVABLE AX = 4408h BL = drive number (00h = default, 01h = A:, etc) Return: CF clear if successful AX = 0000h if removable = 0001h if fixed CF set on error AX = error code (01h,0Fh) (see AH=59h) SeeAlso: AX=4400h,AX=4409h,INT 2F/AX=122Bh --------D-214409----------------------------- INT 21 - DOS 3.1+ - IOCTL - CHECK IF BLOCK DEVICE REMOTE AX = 4409h BL = drive number (00h = default, 01h = A:, etc) Return: CF clear if successful DX = device attribute word bit 15: drive is SUBSTituted bit 12: drive is remote bit 9: direct I/O not allowed CF set on error AX = error code (01h,0Fh) (see AH=59h) Note: on local drives, DX bits not listed above are the attribute word from the device driver header (see AH=52h); for remote drives, the other bits appear to be undefined for DOS versions prior to 5.0 (they are all cleared in DOS 5+) SeeAlso: AX=4400h,AX=4408h,AX=440Ah,INT 2F/AX=122Bh --------D-21440A----------------------------- INT 21 - DOS 3.1+ - IOCTL - CHECK IF HANDLE IS REMOTE AX = 440Ah BX = handle Return: CF clear if successful DX = attribute word (as stored in SFT) bit 15: set if remote bit 14: date/time not set on close CF set on error AX = error code (01h,06h) (see AH=59h) Note: if file is remote, Novell Advanced NetWare 2.0 returns the number of the file server on which the handle is located in CX SeeAlso: AX=4400h,AX=4409h,AH=52h,INT 2F/AX=122Bh --------D-21440B----------------------------- INT 21 - DOS 3.1+ - IOCTL - SET SHARING RETRY COUNT AX = 440Bh CX = pause between retries (default 1) DX = number of retries (default 3) Return: CF clear if successful CF set on error AX = error code (01h) (see AH=59h) Notes: delay is dependent on processor speed (value in CX specifies number of 64K-iteration empty loops to execute) if DX=0000h on entry, the retry count is left unchanged SeeAlso: AH=52h,INT 2F/AX=1224h,INT 2F/AX=122Bh --------D-21440C----------------------------- INT 21 - DOS 3.2+ - IOCTL - GENERIC CHARACTER DEVICE REQUEST AX = 440Ch BX = device handle CH = category code 00h unknown (DOS 3.3+) 01h COMn: (DOS 3.3+) 03h CON (DOS 3.3+) 05h LPTn: 9Eh Media Access Control driver (STARLITE) 00h-7Fh reserved for Microsoft 80h-FFh reserved for OEM/user-defined CL = function 00h MAC driver Bind (STARLITE) 45h set iteration count 4Ah select code page 4Ch start code-page preparation 4Dh end code-page preparation 5Fh set display information (DOS 4+) 65h get iteration count 6Ah query selected code page 6Bh query prepare list 7Fh get display information (DOS 4+) DS:DX -> (DOS) parameter block (see below) SI = parameter to pass to driver (European MS-DOS 4.0, OS/2 comp box) DI = parameter to pass to driver (European MS-DOS 4.0, OS/2 comp box) Return: CF set on error AX = error code (see AH=59h) CF clear if successful DS:DX -> iteration count if CL=65h SI = returned value (European MS-DOS 4.0, OS/2 comp box) DI = returned value (European MS-DOS 4.0, OS/2 comp box) DS:DX -> (OS/2 comp box) data block Note: bit assignments for function code in CL: bit 7: set to ignore if unsupported, clear to return error bit 6: set if passed to driver, clear if intercepted by DOS bit 5: set if queries data from device, clear if sends command bits 4-0: subfunction SeeAlso: AX=440Dh,INT 2F/AX=0802h,INT 2F/AX=122Bh,INT 2F/AX=14FFh SeeAlso: INT 2F/AX=1A01h Format of parameter block for function 00h: Offset Size Description 00h 8 BYTEs ASCIZ signature "STARMAC" 08h WORD version 0Ah WORD flags bit 0: media requires connect or listen request before use bit 1: network is a LAN (broadcast/multicast supported) bit 2: point-to-point network 0Ch WORD handle for use with MAC driver's private interface (filled in by MAC driver) 0Eh WORD context 10h WORD approximate speed in KB/sec (filled in by MAC driver) 12h WORD approximate cost in cents per hour (filled in by MAC driver) 14h WORD maximum packet size in bytes (filled in by MAC driver) 16h WORD addressing format (filled in by MAC driver) 0000h general addressing 0001h Ethernet addressing 0002h Token Ring addressing 0003h Token Bus addressing 18h DWORD Send entry point (filled in by MAC driver) 1Ch DWORD RegisterEventHandler entry point (filled in by MAC driver) 20h DWORD SetPacketFilter entry point (filled in by MAC driver) 24h DWORD UnBind entry point (filled in by MAC driver) Format of parameter block for function 45h: Offset Size Description 00h WORD number of times output is attempted before driver assumes device is busy Format of parameter block for functions 4Ah and 6Ah: Offset Size Description 00h WORD length of data 02h WORD code page ID 04h 2N BYTEs DCBS (double byte character set) lead byte range start/end for each of N ranges (DOS 4.0) WORD 0000h end of data (DOS 4.0) Format of parameter block for function 4Ch: Offset Size Description 00h WORD flags DISPLAY.SYS = 0000h PRINTER.SYS bit 0 clear to prepare downloaded font, set to prepare cartridge selection 02h WORD length of remainder of parameter block 04h WORD number of code pages following 06h N WORDs code page 1,...,N Format of parameter block for function 4Dh: Offset Size Description 00h WORD length of data 02h WORD code page ID Format of parameter block for functions 5Fh and 7Fh: Offset Size Description 00h BYTE level (0 for DOS 4.x-6.0) 01h BYTE reserved (0) 02h WORD length of following data (14) 04h WORD control flags bit 0 set for blink, clear for intensity bits 1 to 15 reserved 06h BYTE mode type (1=text, 2=graphics) 07h BYTE reserved (0) 08h WORD colors 0 = monochrome else N bits per pixel 0Ah WORD pixel columns 0Ch WORD pixel rows 0Eh WORD character columns 10h WORD character rows Format of parameter block for function 6Bh: Offset Size Description 00h WORD length of following data 02h WORD number of hardware code pages 04h N WORDs hardware code pages 1,...,N WORD number of prepared code pages N WORDs prepared code pages 1,...,N --------d-21440C----------------------------- INT 21 - Greg Shenaut ASPITAPE.SYS - INTERFACE AX = 440Ch BX = device handle CH = category code 07h tape (ASPITAPE.SYS) CL = function 01h "mtop" - perform tape operation 02h "mtget" - get tape status 03h ignore end-of-tape errors 04h enable end-of-tape errors DS:DX -> parameter block (see below) Return: CF set on error AX = error code (see AH=59h) CF clear if successful DS:DX -> data block Notes: This device driver is a simple DOS interface to the Adaptec Advanced SCSI Programming Interface (ASPI). It provides the following device names as access to the SCSI tape, 'RMTx' (rewind on close) and 'NRMTx' (NO rewind on close) where x can go from 0 to 3. There may also be the following names 'MTx' and 'NMTx' which default to 1024 byte blocks. The names may also have a '$' appended to try and make them unique from file names of 'RMT0' etc. once opend these devices must be put into RAW mode SeeAlso: AX=4402h"ASPI" Format of mtop parameter block: Offset Size Description 00h WORD operation code 00h "MTWEOF" - write an end-of-file record 01h "MTFSF" - forward space file 02h "MTBSF" - backward space file 03h "MTFSR" - forward space record 04h "MTBSR" - backward space record 05h "MTREW" - rewind 06h "MTOFFL" - rewind and unload 07h "MTNOP" - perform TEST UNIT READY 02h DWORD repetition count Format of mtget parameter block: Offset Size Description 00h BYTE ASPI host ID 01h BYTE SCSI target ID 02h BYTE SCSI logical unit number 03h BYTE device parameters bit 0: drive must use fixed-block read and write bit 7: drive is an ASPI device 04h BYTE current device state (see below) 05h BYTE unit number within driver 06h WORD fixed block blocksize 08h BYTE last SCSI status 09h BYTE last SCSI sense key 0Ah WORD last SCSI opcode (packed) bits 0-7: SCSI operation (SCSI packet byte 0) bits 8-10: SCSI flags (SCSI packet byte 1) bits 11-12: ASPI "Direction Bits" (ASPI SRB byte 3) 0Ch WORD residual bytes from SCSI opcode Bitfields for current device state: bit 0 device currently opened in buffered mode bit 1 drive currently opened in nonbuffered mode bit 2 rewind drive on last close bit 3 drive has been written on bit 4 drive has been read from bit 5 next read will return 0 bytes bit 6 EOM will resemble EOF bit 7 drive may be busy rewinding --------D-21440D----------------------------- INT 21 - DOS 3.2+ - IOCTL - GENERIC BLOCK DEVICE REQUEST AX = 440Dh BL = drive number (00h=default,01h=A:,etc) CH = category code 08h disk drive 00h-7Fh reserved for Microsoft 80h-FFh reserved for OEM/user-defined CL = function 00h (OS/2) \ used to lock/unlock a drive 01h (OS/2) / 40h set device parameters 41h write logical device track 42h format and verify logical device track 46h (DOS 4+) set volume serial number (see also AH=69h) 47h (DOS 4+) set access flag 60h get device parameters 61h read logical device track 62h verify logical device track 66h (DOS 4+) get volume serial number (see also AH=69h) 67h (DOS 4+) get access flag 68h (DOS 5+) sense media type DS:DX -> (DOS) parameter block (see below) SI:DI -> (OS/2 comp box) parameter block (see below) Return: CF set on error AX = error code (01h,02h) (see AH=59h) CF clear if successful DS:DX -> data block if CL=60h or CL=61h Notes: DOS 4.01 seems to ignore the high byte of the number of directory entries in the BPB for diskettes. functions 46h and 66h undocumented in DOS 4.x, documented for DOS 5+ the DUBLDISK.SYS v2.6 driver only supports minor codes 60h and 67h SeeAlso: AX=440Ch,AH=69h,INT 2F/AX=0802h,INT 2F/AX=122Bh Format of parameter block for functions 40h, 60h: Offset Size Description 00h BYTE special functions bit 0 set if function to use current BPB, clear if Device BIOS Parameter Block field contains new default BPB bit 1 set if function to use track layout fields only must be clear if CL=60h bit 2 set if all sectors in track same size (should be set) bits 3-7 reserved 01h BYTE device type 00h 320K/360K disk 01h 1.2M disk 02h 720K disk 03h single-density 8-inch disk 04h double-density 8-inch disk 05h fixed disk 06h tape drive 07h (DOS 3.3+) 1.44M floppy 08h read/write optical disk 09h (DOS 5+) 2.88M floppy 0Ah other type of block device 02h WORD device attributes bit 0 set if nonremovable medium bit 1 set if door lock ("changeline") supported bits 2-15 reserved 04h WORD number of cylinders 06h BYTE media type for 1.2M drive 00h 1.2M disk (default) 01h 320K/360K disk F8h for DUBLDISK.SYS v2.6 expanded drives always 00h for other drive types 07h 31 BYTEs device BPB (see AH=53h), bytes after BPB offset 1Eh omitted ---function 40h only--- 26h WORD number of sectors per track (start of track layout field) max 63 28h N word pairs: number,size of each sector in track Format of parameter block for functions 41h, 61h: Offset Size Description 00h BYTE special functions (reserved, must be zero) 01h WORD number of disk head 03h WORD number of disk cylinder 05h WORD number of first sector to read/write 07h WORD number of sectors 09h DWORD transfer address Format of parameter block for function 42h: Offset Size Description 00h BYTE reserved, must be zero (DOS <3.2) bit 0=0: format/verify track 1: format status call (DOS 3.2+), don't actually format bits 1-7 reserved, must be zero on return (DOS 4.x): bit 0: set if specified tracks, sectors/track supported bit 1: set if function not supported by BIOS bit 2: set if specified tracks, sectors/track not supported bit 3: set if no disk in drive 01h WORD number of disk head 03h WORD number of disk cylinder Format of parameter block for function 62h: Offset Size Description 00h BYTE reserved, must be zero (DOS <3.2) bit 0=0: verify single track 1: verify multiple tracks bits 1-7 reserved, must be zero on return (DOS 4.x): bit 0: set if specified tracks, sectors/track supported bit 1: set if function not supported by BIOS bit 2: set if specified tracks, sectors/track not supported bit 3: set if no disk in drive 01h WORD number of disk head 03h WORD number of disk cylinder 05h WORD number of tracks to verify (equivalent to 255 or fewer sectors) Format of parameter block for functions 46h, 66h: Offset Size Description 00h WORD (call) info level (should be 0000h) 02h DWORD disk serial number (binary) 06h 11 BYTEs volume label or "NO NAME " 11h 8 BYTEs filesystem type "FAT12 " or "FAT16 " (CL=66h only) Format of parameter block for functions 47h, 67h: Offset Size Description 00h BYTE special-function field (must be zero) 01h BYTE disk-access flag, nonzero if access allowed by driver Format of parameter block for function 68h: Offset Size Description 00h BYTE 01h for default media type, 00h for any other media type (see also INT 13/AH=20h) 01h BYTE 02h for 720K, 07h for 1.44M, 09h for 2.88M --------D-21440E----------------------------- INT 21 - DOS 3.2+ - IOCTL - GET LOGICAL DRIVE MAP AX = 440Eh BL = drive number (00h=default,01h=A:,etc) Return: CF set on error AX = error code (01h,0Fh) (see AH=59h) CF clear if successful AL = 00h block device has only one logical drive assigned 1..26 the last letter used to reference the drive (1=A:,etc) SeeAlso: AX=440Fh,INT 2F/AX=122Bh --------D-21440F----------------------------- INT 21 - DOS 3.2+ - IOCTL - SET LOGICAL DRIVE MAP AX = 440Fh BL = physical drive number (00h=default,01h=A:,etc)) Return: CF set on error AX = error code (01h,0Fh) (see AH=59h) CF clear if successful drive now responds to next logical drive number Note: maps logical drives to physical drives, similar to DOS's treatment of a single physical floppy drive as both A: and B: SeeAlso: AX=440Eh,INT 2F/AX=122Bh --------D-214410----------------------------- INT 21 - DOS 5+ - IOCTL - QUERY GENERIC IOCTL CAPABILITY (HANDLE) AX = 4410h BX = handle for device CH = category code (see AX=440Ch) CL = function code Return: CF clear if successful AX = 0000h specified IOCTL function is supported CF set on error AL = 01h IOCTL capability not available Note: a program which wishes to use Generic IOCTL calls beyond those in the standard DOS 3.2 set may use this call first to see whether a particular call is supported SeeAlso: AX=440Ch,AX=440Dh,AX=4411h --------d-214410BXFFFF----------------------- INT 21 U - NewSpace - ENABLE DRIVER AX = 4410h BX = FFFFh Program: NewSpace is a TSR by Isogon Corporation which automatically compresses all files as they are written and decompresses them as they are read Note: compressed files are not accessible unless the driver is enabled SeeAlso: AX=4411h/BX=FFFFh --------D-214411----------------------------- INT 21 - DOS 5+ - IOCTL - QUERY GENERIC IOCTL CAPABILITY (DRIVE) AX = 4411h BL = drive number CH = category code (see AX=440Dh) CL = function code Return: CF clear if successful AX = 0000h specified IOCTL function is supported CF set on error AL = 01h IOCTL capability not available Note: a program which wishes to use Generic IOCTL calls beyond those in the standard DOS 3.2 set may use this call first to see whether a particular call is supported SeeAlso: AX=440Ch,AX=440Dh,AX=4410h --------d-214411BXFFFF----------------------- INT 21 U - NewSpace - DISABLE DRIVER AX = 4411h BX = FFFFh Program: NewSpace is a TSR by Isogon Corporation which automatically compresses all files as they are written and decompresses them as they are read Note: compressed files are not accessible unless the driver is enabled SeeAlso: AX=4410h/BX=FFFFh --------O-214412----------------------------- INT 21 - DR-DOS 5+ - DETERMINE DOS TYPE AX = 4412h CF set Return: CF set if not DR-DOS AX = error code (see AH=59h) CF clear if DR-DOS DX = AX = version code (see AX=4452h) Note: this obsolete call which will not be supported in future versions of DR-DOS is identical to AX=4452h SeeAlso: AX=4452h --------d-214412BXFFFF----------------------- INT 21 U - NewSpace - INSTALLATION CHECK??? AX = 4412h BX = FFFFh Return: AX = PSP segment of NewRes (resident driver for NewSpace) BX:DX -> ??? CX = ??? SeeAlso: AX=4411h/BX=FFFFh --------d-214413BXFFFF----------------------- INT 21 U - NewSpace - GET ??? AX = 4413h BX = FFFFh Return: AX = code segment of NewRes (resident driver for NewSpace) BX = offset of ??? SeeAlso: AX=4412h/BX=FFFFh --------O-214414----------------------------- INT 21 U - DR-DOS 5.0 - SET GLOBAL PASSWORD AX = 4414h DS:DX -> password string (blank-padded to 8 characters) Desc: Specify the master password for accessing files. Note: this obsolete call which will not be supported in future versions of DR-DOS is identical to AX=4452h SeeAlso: AX=4454h --------d-214414BXFFFF----------------------- INT 21 U - NewSpace - DEBUGGING DUMP AX = 4414h BX = FFFFh Return: debugging dump written to X:\NEWSPACE.SMP SeeAlso: AX=4413h/BX=FFFFh,AX=44FFh/BX=FFFFh --------O-2144------------------------------- INT 21 U - DR-DOS 5.0 - HISTORY BUFFER, SHARE, AND HILOAD CONTROL AH = 44h AL = 16h to 18h Note: these obsolete subfunctions (which will not be supported in future versions of DR-DOS) are identical to AX=4456h through 4458h SeeAlso: AX=4456h,AX=4457h,AX=4458h --------O-214451----------------------------- INT 21 - Concurrent DOS v3.2+ - INSTALLATION CHECK AX = 4451h Return: CF set if not Concurrent DOS AX = error code (see AH=59h) CF clear if successful AH = single-tasking/multitasking nature 10h single-tasking AL = operating system version ID (see AX=4452h) 14h multitasking AL = operating system version ID (see below) Notes: as of Concurrent DOS/XM 5.0 (possibly earlier), the version is stored in the environment variable VER use this function if you are looking for multitasking capabilities, AX=4452h for single-tasking this function should never return the single-tasking values SeeAlso: AX=4452h,AX=4459h Values for operating system version ID: 32h Concurrent PC DOS 3.2 41h Concurrent DOS 4.1 50h Concurrent DOS/XM 5.0 or Concurrent DOS/386 1.1 60h Concurrent DOS/XM 6.0 or Concurrent DOS/386 2.0 62h Concurrent DOS/XM 6.2 or Concurrent DOS/386 3.0 66h DR Multiuser DOS 5.1 --------O-214452----------------------------- INT 21 - DR-DOS 3.41+ - DETERMINE DOS TYPE/GET DR-DOS VERSION AX = 4452h CF set Return: CF set if not DR-DOS AX = error code (see AH=59h) CF clear if DR-DOS DX = AX = version code AH = single-tasking/multitasking 10h single-tasking AL = operating system version ID (see below) 14h multitasking AL = operating system version ID (see AX=4451h) Notes: the DR-DOS version is stored in the environment variable VER use this function if looking for single-tasking capabilities, AX=4451h if looking for multitasking; this call should never return multi- tasking values SeeAlso: AX=4412h,AX=4451h,AX=4459h Values for operating system version ID: 60h DOS Plus 63h DR-DOS 3.41 64h DR-DOS 3.42 65h DR-DOS 5.00 67h DR-DOS 6.00 70h PalmDOS --------O-214454----------------------------- INT 21 U - DR-DOS 3.41+ - SET GLOBAL PASSWORD AX = 4454h DS:DX -> password string (blank-padded to 8 characters) Desc: Specify the master password for accessing files. SeeAlso: AX=4303h,AX=4414h --------O-214456----------------------------- INT 21 U - DR-DOS 5.0+ - HISTORY BUFFER CONTROL AX = 4456h DL = flag bit 0: 1 = COMMAND.COM history buffers 0 = set to application Return: AL = ??? (20h if DL bit 0 set, A0h if clear (DR-DOS 6.0)) Note: This was seen called by COMMAND.COM of DR-DOS 6.0 --------O-214457----------------------------- INT 21 U - DR-DOS 5.0+ - SHARE/HILOAD CONTROL AX = 4457h DH = subfunction 00h enable/disable SHARE DL = 00h disable = 01h enable else Return: AX = ??? 01h get HILOAD status Return: AX = status 0000h off 0001h on 02h set HILOAD status DL = new state (00h off, 01h on) Return: AX = ??? other Return: AX = ??? Note: This was seen called by COMMAND.COM of DR-DOS 6.0 SeeAlso: AX=4457h/DX=FFFFh --------O-214457DXFFFF----------------------- INT 21 U - DR-DOS 6.0 - GET SHARE STATUS AX = 4457h DX = FFFFh Return: AX = SHARE status SeeAlso: INT 2F/AX=1000h --------O-214458----------------------------- INT 21 U - DR-DOS 5.0+ internal - GET POINTER TO TABLE OF ??? AX = 4458h Return: ES:BX -> internal table (see below) AX = ??? (0B50h for DR-DOS 5.0, 0A56h for DR-DOS 6.0) SeeAlso: AX=4452h Format of internal table: Offset Size Description 00h DWORD pointer to ??? 04h 7 BYTEs ??? 0Bh WORD K of extended memory at startup 0Dh BYTE number of far jump entry points 0Eh WORD segment containing far jumps to DR-DOS entry points (see below) ---DR-DOS 6.0--- 10h WORD (only if kernel loaded in HMA) offset in HMA of first free HMA memory block (see below) or 0000h if none; segment is FFFFh 12h WORD pointer to segment of environment variables set in CONFIG, or 0000h if already used 14h WORD (only if kernel loaded in HMA) offset in HMA of first used HMA memory block (see below) or 0000h if none; segment is FFFFh Note: the segment used for the DR-DOS 6.0 CONFIG environment variables (excluding COMSPEC, VER and OS) is only useful for programs/drivers called from CONFIG.SYS. The word is set to zero later and the area lost. Format of kernel entry jump table for DR-DOS 5.0-6.0: Offset Size Description 00h 5 BYTEs far jump to kernel entry point for CP/M CALL 5 05h 5 BYTEs far jump to kernel entry point for INT 20 0Ah 5 BYTEs far jump to kernel entry point for INT 21 0Fh 5 BYTEs far jump to kernel entry point for INT 22??? (RETF) 14h 5 BYTEs far jump to kernel entry point for INT 23??? (RETF) 19h 5 BYTEs far jump to kernel entry point for INT 24 1Eh 5 BYTEs far jump to kernel entry point for INT 25 23h 5 BYTEs far jump to kernel entry point for INT 26 28h 5 BYTEs far jump to kernel entry point for INT 27 2Dh 5 BYTEs far jump to kernel entry point for INT 28 32h 5 BYTEs far jump to kernel entry point for INT 2A (IRET) 37h 5 BYTEs far jump to kernel entry point for INT 2B (IRET) 3Ch 5 BYTEs far jump to kernel entry point for INT 2C (IRET) 41h 5 BYTEs far jump to kernel entry point for INT 2D (IRET) 46h 5 BYTEs far jump to kernel entry point for INT 2E (IRET) 4Bh 5 BYTEs far jump to kernel entry point for INT 2F Note: all of these entry points are indirected through this jump table to allow the kernel to be relocated into high memory while leaving the actual entry addresses in low memory for maximum compatibility Format of HMA Memory Block (DR-DOS 6.0 kernel loaded in HMA): Offset Size Description 00h WORD offset of next HMA Memory Block (0000h if last block) 02h WORD size of this block in bytes (at least 10h) 04h BYTE type of HMA Memory Block (interpreted by MEM) 00h system 01h KEYB 02h NLSFUNC 03h SHARE 04h TaskMAX 05h COMMAND 05h var TSR (or system) code and data. DR-DOS TSR's, such as KEYB, hooks interrupts using segment FFFEh instead FFFFh. --------O-214459----------------------------- INT 21 - DR MultiUser DOS 5.0 - API AX = 4459h CL = function (see INT E0"CP/M") DS,DX = parameters Notes: DR-DOS 5.0 returns CF set and AX=0001h this API is also available on INT E0 SeeAlso: AX=4452h,INT E0"CP/M" --------d-2144FFBXFFFF----------------------- INT 21 U - NewSpace - ??? AX = 44FFh BX = FFFFh DX = ??? Program: NewSpace is a TSR by Isogon Corporation which automatically compresses all files as they are written and decompresses them as they are read SeeAlso: AX=4414h/BX=FFFFh --------D-2145------------------------------- INT 21 - DOS 2+ - "DUP" - DUPLICATE FILE HANDLE AH = 45h BX = file handle Return: CF clear if successful AX = new handle CF set on error AX = error code (04h,06h) (see AH=59h) Notes: moving file pointer for either handle will also move it for the other, because both will refer to the same system file table for DOS versions prior to 3.3, file writes may be forced to disk by duplicating the file handle and closing the duplicate SeeAlso: AH=3Dh,AH=46h --------D-2146------------------------------- INT 21 - DOS 2+ - "DUP2", "FORCEDUP" - FORCE DUPLICATE FILE HANDLE AH = 46h BX = file handle CX = file handle to become duplicate of first handle Return: CF clear if successful CF set on error AX = error code (04h,06h) (see AH=59h) Notes: closes file with handle CX if it is still open DOS 3.30 hangs if BX=CX on entry moving file pointer for either handle will also move it for the other, because both will refer to the same system file table SeeAlso: AH=3Dh,AH=45h --------D-2147------------------------------- INT 21 - DOS 2+ - "CWD" - GET CURRENT DIRECTORY AH = 47h DL = drive number (00h = default, 01h = A:, etc) DS:SI -> 64-byte buffer for ASCIZ pathname Return: CF clear if successful AX = 0100h (undocumented) CF set on error AX = error code (0Fh) (see AH=59h) Notes: the returned path does not include a drive or the initial backslash many Microsoft products for Windows rely on AX being 0100h on success under the FlashTek X-32 DOS extender, the buffer pointer is in DS:ESI SeeAlso: AH=19h,AH=3Bh,INT 15/AX=DE25h --------D-2148------------------------------- INT 21 - DOS 2+ - ALLOCATE MEMORY AH = 48h BX = number of paragraphs to allocate Return: CF clear if successful AX = segment of allocated block CF set on error AX = error code (07h,08h) (see AH=59h) BX = size of largest available block Notes: DOS 2.1-6.0 coalesces free blocks while scanning for a block to allocate .COM programs are initially allocated the largest available memory block, and should free some memory with AH=49h before attempting any allocations under the FlashTek X-32 DOS extender, EBX contains a protected-mode near pointer to the allocated block on a successful return SeeAlso: AH=49h,AH=4Ah,AH=58h,AH=83h --------D-2149------------------------------- INT 21 - DOS 2+ - FREE MEMORY AH = 49h ES = segment of block to free Return: CF clear if successful CF set on error AX = error code (07h,09h) (see AH=59h) Notes: apparently never returns an error 07h, despite official docs; DOS 3.30 code contains only an error 09h exit DOS 2.1-6.0 does not coalesce adjacent free blocks when a block is freed, only when a block is allocated or resized SeeAlso: AH=48h,AH=4Ah --------D-214A------------------------------- INT 21 - DOS 2+ - RESIZE MEMORY BLOCK AH = 4Ah BX = new size in paragraphs ES = segment of block to resize Return: CF clear if successful CF set on error AX = error code (07h,08h,09h) (see AH=59h) BX = maximum paragraphs available for specified memory block Notes: under DOS 2.1-5.0, if there is insufficient memory to expand the block as much as requested, the block will be made as large as possible DOS 2.1-5.0 coalesces any free blocks immediately following the block to be resized SeeAlso: AH=48h,AH=49h,AH=83h --------D-214B------------------------------- INT 21 - DOS 2+ - "EXEC" - LOAD AND/OR EXECUTE PROGRAM AH = 4Bh AL = type of load 00h load and execute 01h load but do not execute 03h load overlay 04h load and execute in background (European MS-DOS 4.0 only) "Exec & Go" (see also AH=80h) DS:DX -> ASCIZ program name (must include extension) ES:BX -> parameter block (see below) CX = mode (subfunction 04h only) 0000h child placed in zombie mode after termination 0001h child's return code discarded on termination Return: CF clear if successful BX,DX destroyed if subfunction 01h, process ID set to new program's PSP; get with INT 21/AH=62h CF set on error AX = error code (01h,02h,05h,08h,0Ah,0Bh) (see AH=59h) Notes: DOS 2.x destroys all registers, including SS:SP for functions 00h and 01h, the calling process must ensure that there is enough unallocated memory available; if necessary, by releasing memory with AH=49h or AH=4Ah for function 01h, the AX value to be passed to the child program is put on top of the child's stack for function 03h, DOS assumes that the overlay is being loaded into memory allocated by the caller function 01h was undocumented prior to the release of DOS 5.0 some versions (such as DR-DOS 6.0) check the parameters and parameter block and return an error if an invalid value (such as an offset of FFFFh) is found background programs under European MS-DOS 4.0 must use the new executable format new executables begin running with the following register values AX = environment segment BX = offset of command tail in environment segment CX = size of automatic data segment (0000h = 64K) ES,BP = 0000h DS = automatic data segment SS:SP = initial stack the command tail corresponds to an old executable's PSP:0081h and following, except that the 0Dh is turned into a NUL (00h); new format executables have no PSP under the FlashTek X-32 DOS extender, only function 00h is supported and the pointers are passed in DS:EDX and ES:EBX names for the various executable type understood by various environments: MZ old-style DOS executable NE Windows or OS/2 1.x segmented ("new") executable LE Windows virtual device driver (VxD) linear executable LX variant of LE used in OS/2 2.x W3 Windows WIN386.EXE file; a collection of LE files PE Win32 (Windows NT and Win32s) portable executable based on Unix COFF BUGS: DOS 2.00 assumes that DS points at the current program's PSP Load Overlay (subfunction 03h) loads up to 512 bytes too many if the file contains additional data after the actual overlay SeeAlso: AX=4B05h,AH=4Ch,AH=4Dh,AH=64h"OS/2",AH=8Ah,INT 2E Format of EXEC parameter block for AL=00h,01h,04h: Offset Size Description 00h WORD segment of environment to copy for child process (copy caller's environment if 0000h) 02h DWORD pointer to command tail to be copied into child's PSP 06h DWORD pointer to first FCB to be copied into child's PSP 0Ah DWORD pointer to second FCB to be copied into child's PSP 0Eh DWORD (AL=01h) will hold subprogram's initial SS:SP on return 12h DWORD (AL=01h) will hold entry point (CS:IP) on return Format of EXEC parameter block for AL=03h: Offset Size Description 00h WORD segment at which to load overlay 02h WORD relocation factor to apply to overlay if in .EXE format Format of EXEC parameter block for FlashTek X-32: Offset Size Description 00h PWORD 48-bit far pointer to environment string 06h PWORD 48-bit far pointer to command tail string Format of .EXE file header: Offset Size Description 00h 2 BYTEs .EXE signature, either "MZ" or "ZM" (5A4Dh or 4D5Ah) 02h WORD number of bytes in last 512-byte page of executable 04h WORD total number of 512-byte pages in executable (includes any partial last page) 06h WORD number of relocation entries 08h WORD header size in paragraphs 0Ah WORD minimum paragraphs of memory to allocation in addition to executable's size 0Ch WORD maximum paragraphs to allocate in addition to executable's size 0Eh WORD initial SS relative to start of executable 10h WORD initial SP 12h WORD checksum (one's complement of sum of all words in executable) 14h DWORD initial CS:IP relative to start of executable 18h WORD offset within header of relocation table 40h or greater for new-format (NE,LE,LX,W3,PE,etc.) executable 1Ah WORD overlay number (normally 0000h = main program) ---new executable--- 1Ch 4 BYTEs ??? 20h WORD behavior bits 22h 26 BYTEs reserved for additional behavior info 3Ch DWORD offset of new executable (NE,LE,etc) header within disk file, or 00000000h if plain MZ executable ---Borland TLINK--- 1Ch 2 BYTEs ??? (apparently always 01h 00h) 1Eh BYTE signature FBh 1Fh BYTE TLINK version (major in high nybble, minor in low nybble) 20h 2 BYTEs ??? (v2.0 apparently always 72h 6Ah, v3.0+ seems always 6Ah 72h) ---ARJ self-extracting archive--- 1Ch 4 BYTEs signature "RJSX" (older versions, new signature is "aRJsfX" in the first 1000 bytes of the file) ---LZEXE 0.90 compressed executable--- 1Ch 4 BYTEs signature "LZ09" ---LZEXE 0.91 compressed executable--- 1Ch 4 BYTEs signature "LZ91" ---PKLITE compressed executable--- 1Ch BYTE minor version number 1Dh BYTE bits 0-3: major version bit 4: extra compression bit 5: huge (multi-segment) file 1Eh 6 BYTEs signature "PKLITE" (followed by copyright message) ---LHarc 1.x self-extracting archive--- 1Ch 4 BYTEs unused??? 20h 3 BYTEs jump to start of extraction code 23h 2 BYTEs ??? 25h 12 BYTEs signature "LHarc's SFX " ---LHA 2.x self-extracting archive--- 1Ch 8 BYTEs ??? 24h 10 BYTEs signature "LHa's SFX " (v2.10) or "LHA's SFX " (v2.13) ---TopSpeed C 3.0 CRUNCH compressed file--- 1Ch DWORD 018A0001h 20h WORD 1565h ---PKARCK 3.5 self-extracting archive--- 1Ch DWORD 00020001h 20h WORD 0700h ---BSA (Soviet archiver) self-extracting archive--- 1Ch WORD 000Fh 1Eh BYTE A7h ---LARC self-extracting archive--- 1Ch 4 BYTEs ??? 20h 11 BYTEs "SFX by LARC " ---LH self-extracting archive--- 1Ch 8 BYTEs ??? 24h 8 BYTEs "LH's SFX " ---other linkers--- 1Ch var optional information --- N N DWORDs relocation items Notes: if word at offset 02h is 4, it should be treated as 00h, since pre-1.10 versions of the MS linker set it that way if both minimum and maximum allocation (offset 0Ah/0Ch) are zero, the program is loaded as high in memory as possible the maximum allocation is set to FFFFh by default Format of new executable header: Offset Size Description 00h 2 BYTEs "NE" (4Eh 45h) signature 02h 2 BYTEs linker version (major, then minor) 04h WORD offset from start of this header to entry table (see below) 06h WORD length of entry table in bytes 08h DWORD file load CRC (0 in Borland's TPW) 0Ch BYTE program flags bits 0-1 DGROUP type 0 = none 1 = single shared 2 = multiple (unshared) 3 = (null) bit 2: global initialization bit 3: protected mode only bit 4: 8086 instructions bit 5: 80286 instructions bit 6: 80386 instructions bit 7: 80x87 instructions 0Dh BYTE application flags bits 0-2: application type 001 full screen (not aware of Windows/P.M. API) 010 compatible with Windows/P.M. API 011 uses Windows/P.M. API bit 3: is a Family Application (OS/2) bit 5: 0=executable, 1=errors in image bit 6: non-conforming program (valid stack is not maintained) bit 7: DLL or driver rather than application (SS:SP info invalid, CS:IP points at FAR init routine called with AX=module handle which returns AX=0000h on failure, AX nonzero on successful initialization) 0Eh WORD auto data segment index 10h WORD initial local heap size 12h WORD initial stack size (added to data seg, 0000h if SS != DS) 14h DWORD program entry point (CS:IP), "CS" is index into segment table 18h DWORD initial stack pointer (SS:SP), "SS" is segment index if SS=automatic data segment and SP=0000h, the stack pointer is set to the top of the automatic data segment, just below the local heap 1Ch WORD segment count 1Eh WORD module reference count 20h WORD length of nonresident names table in bytes 22h WORD offset from start of this header to segment table (see below) 24h WORD offset from start of this header to resource table 26h WORD offset from start of this header to resident names table 28h WORD offset from start of this header to module reference table 2Ah WORD offset from start of this header to imported names table (array of counted strings, terminated with a string of length 00h) 2Ch DWORD offset from start of file to nonresident names table 30h WORD count of moveable entry point listed in entry table 32h WORD file alignment size shift count 0 is equivalent to 9 (default 512-byte pages) 34h WORD number of resource table entries 36h BYTE target operating system 00h unknown 01h OS/2 02h Windows 03h European MS-DOS 4.x 04h Windows 386 05h BOSS (Borland Operating System Services) 37h BYTE other EXE flags bit 0: supports long filenames bit 1: 2.X protected mode bit 2: 2.X proportional font bit 3: gangload area 38h WORD offset to return thunks or start of gangload area 3Ah WORD offset to segment reference thunks or length of gangload area 3Ch WORD minimum code swap area size 3Eh 2 BYTEs expected Windows version (minor version first) Note: this header is documented in detail in the Windows 3.1 SDK Programmer's Reference, Vol 4. Format of Codeview trailer (at end of executable): Offset Size Description 00h WORD signature 4E42h ('NB') 02h WORD Microsoft debug info version number 04h DWORD Codeview header offset Format of new executable segment table record: 00h WORD offset in file (shift left by alignment shift to get byte offs) 02h WORD length of image in file (0000h = 64K) 04h WORD segment attributes (see below) 06h WORD number of bytes to allocate for segment (0000h = 64K) Note: the first segment table entry is entry number 1 Bitfields for segment attributes: bit 0 data segment rather than code segment bit 1 unused??? bit 2 real mode bit 3 iterated bit 4 movable bit 5 sharable bit 6 preloaded rather than demand-loaded bit 7 execute-only (code) or read-only (data) bit 8 relocations (directly following code for this segment) bit 9 debug info present bits 10,11 80286 DPL bits bit 12 discardable bits 13-15 discard priority Format of new executable entry table item (list): Offset Size Description 00h BYTE number of entry points (00h if end of entry table list) 01h BYTE segment number (00h if end of entry table list) 02h 3N BYTEs entry records Offset Size Description 00h BYTE flags bit 0: exported bit 1: single data bits 2-7: unused??? 01h WORD offset within segment Format of new executable relocation data (immediately follows segment image): Offset Size Description 00h WORD number of relocation items 02h 8N BYTEs relocation items Offset Size Description 00h BYTE relocation type 00h LOBYTE 02h BASE 03h PTR 05h OFFS 0Bh PTR48 0Dh OFFS32 01h BYTE flags bit 2: additive 02h WORD offset within segment 04h WORD target address segment 06h WORD target address offset Format of new executable resource data: Offset Size Description 00h WORD alignment shift count for resource data 02h N RECORDs resources Format of resource record: Offset Size Description 00h WORD type ID 0000h if end of resource records >= 8000h if integer type else offset from start of resource table to type string 02h WORD number of resources of this type 04h DWORD reserved for runtime use 08h N Resources (see below) Note: resource type and name strings are stored immediately following the resource table, and are not null-terminated Format of new executable resource entry: Offset Size Description 00h WORD offset in alignment units from start of file to contents of the resource data 02h WORD length of resource image in bytes 04h WORD flags bit 4: moveable bit 5: shareable bit 6: preloaded 06h WORD resource ID >= 8000h if integer resource else offset from start of resource table to resource string 08h DWORD reserved for runtime use Notes: resource type and name strings are stored immediately following the resource table, and are not null-terminated strings are counted strings, with a string of length 0 indicating the end of the resource table Format of new executable module reference table [one bundle of entries]: Offset Size Description 00h BYTE number of records in this bundle (00h if end of table) 01h BYTE segment indicator 00h unused FFh movable segment, segment number is in entry else segment number of fixed segment 02h N RECORDs Format of segment record Offset Size Description 00h BYTE flags bit 0: entry is exported bit 1: entry uses global (shared) data bits 7-3: number of parameter words ---fixed segment--- 01h WORD offset ---moveable segment--- 01h 2 BYTEs INT 3F instruction (CDh 3Fh) 03h BYTE segment number 05h WORD offset Note: table entries are numbered starting from 1 Format of new executable resident/nonresident name table entry: Offset Size Description 00h BYTE length of string (00h if end of table) 01h N BYTEs ASCII text of string N+1 WORD ordinal number (index into entry table) Notes: the first string in the resident name table is the module name; the first entry in the nonresident name table is the module description the strings are case-sensitive; if the executable was linked with /IGNORECASE, all strings are in uppercase Format of Linear Executable (enhanced mode executable) header: Offset Size Description 00h 2 BYTEs "LE" (4Ch 45h) signature 02h BYTE byte order (00h = little-endian, nonzero = big-endian) 03h BYTE word order (00h = little-endian, nonzero = big-endian) 04h DWORD executable format level 08h WORD CPU type (see also INT 15/AH=C9h) 01h Intel 80286 or upwardly compatible 02h Intel 80386 or upwardly compatible 03h Intel 80486 or upwardly compatible 04h Intel 80586 or upwardly compatible 20h Intel i860 (N10) or compatible 21h Intel "N11" or compatible 40h MIPS Mark I (R2000, R3000) or compatible 41h MIPS Mark II (R6000) or compatible 42h MIPS Mark III (R4000) or compatible 0Ah WORD target operating system 01h OS/2 02h Windows 03h European DOS 4.0 04h Windows 386 0Ch DWORD module version 10h DWORD module type bit 2: initialization (only for DLLs) 0 = global 1 = per-process bit 4: no internal fixups in executable image bit 5: no external fixups in executable image bits 8,9,10: 0 = unknown 1 = incompatible with PM windowing \ 2 = compatible with PM windowing > (only for 3 = uses PM windowing API / programs) bit 13: module not loadable (only for programs) bit 15: module is DLL rather than program 14h DWORD number of memory pages 18h Initial CS:EIP DWORD object number DWORD offset 20h Initial SS:ESP DWORD object number DWORD offset 28h DWORD memory page size 2Ch DWORD bytes on last page 30h DWORD fixup section size 34h DWORD fixup section checksum 38h DWORD loader section size 3Ch DWORD loader section checksum 40h DWORD offset of object table (see below) 44h DWORD object table entries 48h DWORD object page map table offset 4CH DWORD object iterate data map offset 50h DWORD resource table offset 54h DWORD resource table entries 58h DWORD resident names table offset 5Ch DWORD entry table offset 60h DWORD module directives table offset 64h DWORD Module Directives entries 68h DWORD Fixup page table offset 6Ch DWORD Fixup record table offset 70h DWORD imported modules name table offset 74h DWORD imported modules count 78h DWORD imported procedures name table offset 7Ch DWORD per-page checksum table offset 80h DWORD data pages offset 84h DWORD preload page count 88h DWORD non-resident names table offset 8Ch DWORD non-resident names table length 90h DWORD non-resident names checksum 94h DWORD automatic data object 98h DWORD debug information offset 9Ch DWORD debug information length A0h DWORD preload instance pages number A4h DWORD demand instance pages number A8h DWORD extra heap allocation ACh 20 BYTEs reserved C0h WORD device ID (MS-Windows VxD only) C2h WORD DDK version (MS-Windows VxD only) Note: used by EMM386.EXE, QEMM, and Windows 3.0 Enhanced Mode drivers Format of object table entry: Offset Size Description 00h DWORD virtual size in bytes 04h DWORD relocation base address 08h DWORD object flags (see below) 0Ch DWORD page map index 10h DWORD page map entries 14h 4 BYTEs reserved??? (apparently always zeros) Bitfields for object flags: bit 0 readable bit 1 writable bit 2 executable bit 3 resource bit 4 discardable bit 5 shared bit 6 preloaded bit 7 invalid bit 8-9 type 00 normal 01 zero-filled 10 resident 11 resident/contiguous bit 10 "RESIDENT/LONG_LOCKABLE" bit 11 reserved bit 12 "16:16_ALIAS" bit 13 "BIG" (Huge: 32-bit) bit 14 conforming bit 15 "OBJECT_I/O_PRIVILEGE_LEVEL" bits 16-31 reserved Format of object page map table entry: Offset Size Description 00h BYTE ??? (usually 00h) 01h WORD index to fixup table (big-endian) 0000h if no relocation info 03h BYTE type (00h hard copy in file, 03h some relocation needed) Format of resident names table entry: Offset Size Description 00h BYTE length of name 01h N BYTEs name N+1 3 BYTEs ??? Format of linear executable entry table: Offset Size Description 00h BYTE number of entries in table 01h 10 BYTEs per entry Offset Size Description 00h BYTE bit flags bit 0: non-empty bundle bit 1: 32-bit entry 01h WORD object number 03h BYTE entry type flags bit 0: exported bit 1: uses single data rather than instance bit 2: reserved bits 3-7: number of stack parameters 04h DWORD offset of entry point 08h 2 BYTEs ??? Note: empty bundles (bit flags at 00h = 00h) are used to skip unused indices, and do not contain the remaining nine bytes Format of linear executable fixup record: Offset Size Description 00h BYTE type bits 7-4: modifier (0001 single, 0011 multiple) bits 3-0: type 0000 byte offset 0010 word segment 0011 16-bit far pointer (DWORD) 0101 16-bit offset 0110 32-bit far pointer (PWORD) 0111 32-bit offset 1000 near call or jump, WORD/DWORD based on seg attrib 01h BYTE fixup type bit 7: ordinal is BYTE rather than WORD bit 5: addition with DWORD rather than WORD bit 4: reloation info has size with new two bytes at end bit 2: set of add to destination, clear to replace destination bits 1-0: type 00 internal fixup 01 external fixup, imported by ordinal 10 external fixup, imported by name ---if single type--- 02h WORD offset within page 04h relocation information ---internal fixup--- BYTE object number ---external,ordinal--- BYTE one-based module number in Import Module table BYTE/WORD ordinal number WORD/DWORD value to add (only present if modifier bit 4 set) ---external,name--- BYTE one-based module number in Import Module table WORD offset in Import Procedure names WORD/DWORD value to add (only present if modifier bit 4 set) ---if multiple type--- 02h BYTE number of items 03h var relocation info as for "single" type (see above) N WORDs offsets of items to relocate Format of Borland debugging information header (following load image): Offset Size Description 00h WORD signature 52FBh 02h WORD version ID 04h DWORD size of name pool in bytes 08h WORD number of names in namem pool 0Ah WORD number of type entries 0Ch WORD number of structure members 0Eh WORD number of symbols 10h WORD number of global symbols 12h WORD number of modules 14h WORD number of locals (optional) 16h WORD number of scopes in table 18h WORD number of line-number entries 1Ah WORD number of include files 1Ch WORD number of segment records 1Eh WORD number of segment/file correlations 20h DWORD size of load image after removing uninitialized data and debug info 24h DWORD debugger hook; pointer into debugged program whose meaning depends on program flags 28h BYTE program flags bit 0: case-sensitive link bit 1: pascal overlay program 29h WORD no longer used 2Bh WORD size of data pool in bytes 2Dh BYTE padding 2Eh WORD size of following header extension (currently 00h, 10h, or 20h) 30h WORD number of classes 32h WORD number of parents 34h WORD number of global classes (currently unused) 36h WORD number of overloads (currently unused) 38h WORD number of scope classes 3Ah WORD number of module classes 3Ch WORD number of coverage offsets 3Eh DWORD offset relative to symbol base of name pool 42h WORD number of browser information records 44h WORD number of optimized symbol records 46h WORD debugging flags 48h 8 BYTEs padding Note: additional information on the Borland debugging info may be found in Borland's Open Architecture Handbook --------U-214B------------------------------- INT 21 - ELRES v1.0 only - INSTALLATION CHECK AH = 4Bh DS:DX = 0000h:0000h Return: ES:BX -> ELRES history structure (see AH=2Bh/CX=454Ch) DX = DABEh (signature, DAve BEnnett) Program: ELRES is an MS-DOS return code (errorlevel) recorder by David H. Bennett SeeAlso: AH=2Bh/CX=454Ch --------v-214B04----------------------------- INT 21 - VIRUS - "MG", "699"/"Thirteen Minutes" - INSTALLATION CHECK AX = 4B04h Return: CF clear if "MG" resident AX = 044Bh if "699"/"Thirteen Minutes" resident SeeAlso: AX=4243h,AX=4B25h --------D-214B05----------------------------- INT 21 - DOS 5+ - SET EXECUTION STATE AX = 4B05h DS:DX -> execution state structure (see below) Return: CF clear if successful AX = 0000h CF set on error AX = error code (see AH=59h) Note: used by programs which intercept AX=4B00h to prepare new programs for execution (including setting the DOS version number). No DOS, BIOS or other software interrupt may be called after return from this call before commencement of the child process. If DOS is running in the HMA, A20 is turned off on return from this call. SeeAlso: AH=4Bh Format of execution state structure: Offset Size Description 00h WORD reserved (00h) 02h WORD type flags bit 0: program is an .EXE bit 1: program is an overlay 04h DWORD pointer to ASCIZ name of program file 08h WORD PSP segment of new program 0Ah DWORD starting CS:IP of new program 0Eh DWORD program size including PSP --------v-214B25----------------------------- INT 21 - VIRUS - "1063"/"Mono" - INSTALLATION CHECK AX = 4B25h Return: DI = 1234h if resident SeeAlso: AX=4B04h,AX=4B40h --------v-214B40----------------------------- INT 21 - VIRUS - "Plastique"/"AntiCad" - INSTALLATION CHECK AX = 4B40h Return: AX = 5678h if resident SeeAlso: AX=4B25h,AX=4B41h,AX=4B4Ah --------v-214B41----------------------------- INT 21 - VIRUS - "Plastique"/"AntiCad" - ??? AX = 4B41h ??? Return: ??? SeeAlso: AX=4B40h --------v-214B4A----------------------------- INT 21 - VIRUS - "Jabberwocky" - INSTALLATION CHECK AX = 4B4Ah Return: AL = 57h if resident SeeAlso: AX=4B40h,AX=4B4Bh --------v-214B4B----------------------------- INT 21 - VIRUS - "Horse-2" - INSTALLATION CHECK AX = 4B4Bh Return: CF clear if resident SeeAlso: AX=4B4Ah,AX=4B4Dh --------v-214B4D----------------------------- INT 21 - VIRUS - "Murphy-2", "Patricia"/"Smack" - INSTALLATION CHECK AX = 4B4Dh Return: CF clear if resident SeeAlso: AX=4B4Ah,AX=4B50h --------v-214B50----------------------------- INT 21 - VIRUS - "Plastique-2576"/"AntiCad-2576" - INSTALLATION CHECK AX = 4B50h Return: AX = 1234h if resident SeeAlso: AX=4B4Dh,AX=4B53h,AX=4B60h --------v-214B53----------------------------- INT 21 - VIRUS - "Horse" - INSTALLATION CHECK AX = 4B53h Return: CF clear if resident SeeAlso: AX=4B50h,AX=4B55h --------v-214B55----------------------------- INT 21 - VIRUS - "Sparse" - INSTALLATION CHECK AX = 4B55h Return: AX = 1231h if resident SeeAlso: AX=4B53h,AX=4B59h --------v-214B59----------------------------- INT 21 - VIRUS - "Murphy-1", "Murphy-4" - INSTALLATION CHECK AX = 4B59h Return: CF clear if resident SeeAlso: AX=4B50h,AX=4B5Eh --------v-214B5E----------------------------- INT 21 - VIRUS - "Brothers" - INSTALLATION CHECK AX = 4B5Eh Return: CF clear if resident SeeAlso: AX=4B59h,AX=4B87h --------v-214B60----------------------------- INT 21 - VIRUS - "Plastique-2576"/"AntiCad-2576" - ??? AX = 4B60h ??? Return: ??? SeeAlso: AX=4B50h --------v-214B87----------------------------- INT 21 - VIRUS - "Shirley" - INSTALLATION CHECK AX = 4B87h Return: AX = 6663h if resident SeeAlso: AX=4B5Eh,AX=4B95h --------v-214B95----------------------------- INT 21 - VIRUS - "Zherkov-1882" - INSTALLATION CHECK AX = 4B95h Return: AX = 1973h if resident SeeAlso: AX=4B87h,AX=4BA7h --------v-214BA7----------------------------- INT 21 - VIRUS - "1876"/"Dash-em" - INSTALLATION CHECK AX = 4BA7h Return: AX = B459h if resident SeeAlso: AX=4B95h,AX=4BAAh --------v-214BAA----------------------------- INT 21 - VIRUS - "Nomenklatura" - INSTALLATION CHECK AX = 4BAAh Return: CF clear if resident SeeAlso: AX=4BA7h,AX=4BAFh --------v-214BAF----------------------------- INT 21 - VIRUS - "948"/"Screenplus1", "Magnitogorsk" - INSTALLATION CHECK AX = 4BAFh Return: AL = AFh if "Magnitogorsk" resident AL = FAh if "948"/"Screenplus1" resident SeeAlso: AX=4BAAh,AX=4BDDh --------v-214BDD----------------------------- INT 21 - VIRUS - "Lozinsky"/"Zherkov" - INSTALLATION CHECK AX = 4BDDh Return: AX = 1234h SeeAlso: AX=4BAFh,AX=4BFEh --------v-214BEE----------------------------- INT 21 - F-DRIVER.SYS v1.14+ - GRAB INT 21 AX = 4BEEh Return: AX = 1234h if grab successful = 2345h if failed (INT 21 grabbed previously) Notes: F-DRIVER.SYS is part of the F-PROT virus/trojan protection package by Fridrik Skulason when called the first time, this function moves the INT 21 monitoring code from its original location in the INT 21 chain to be the first thing called by INT 21. This is the mechanism used by F-NET. SeeAlso: INT 2F/AX=4653h ----------214BF0----------------------------- INT 21 - DIET v1.10+ (Overlay Mode) - INSTALLATION CHECK AX = 4BF0h Return: CF clear if installed AX = 899Dh Program: DIET is an executable-compression program SeeAlso: AX=4BF1h ----------214BF1----------------------------- INT 21 - DIET v1.10+ (Overlay Mode) - EXPAND PROGRAM??? AX = 4BF1h Return: ??? SeeAlso: AX=4BF0h --------v-214BFE----------------------------- INT 21 - VIRUS - "Hitchcock", "Dark Avenger-1028", "1193" - INSTALLATION CHECK AX = 4BFEh Return: AX = 1234h if "Hitchcock" resident AX = ABCDh if "1193"/"Copyright" resident DI = 55BBh if "Dark Avenger-1028" resident SeeAlso: AX=4BDDh,AX=4BFFh"Justice" --------v-214BFF----------------------------- INT 21 - VIRUS - "USSR-707", "Justice", "Europe 92" - INSTALLATION CHECK AX = 4BFFh Return: BL = FFh if "USSR-707" resident DI = 55AAh if "Justice" resident CF clear if "Europe 92" resident SeeAlso: AX=4BFEh,AX=4BFFh"Cascade",AX=5252h --------v-214BFFSI0000----------------------- INT 21 - VIRUS - "Cascade" - INSTALLATION CHECK AX = 4BFFh SI = 0000h DI = 0000h Return: DI = 55AAh if installed SeeAlso: AX=4BFFh"Justice",AX=5252h --------D-214C------------------------------- INT 21 - DOS 2+ - "EXIT" - TERMINATE WITH RETURN CODE AH = 4Ch AL = return code Return: never returns Notes: unless the process is its own parent (see AH=26h, offset 16h in PSP), all open files are closed and all memory belonging to the process is freed all network file locks should be removed before calling this function SeeAlso: AH=00h,AH=26h,AH=4Bh,AH=4Dh,INT 15/AH=12h/BH=02h,INT 20,INT 22 SeeAlso: INT 60/DI=0601h --------D-214D------------------------------- INT 21 - DOS 2+ - GET RETURN CODE AH = 4Dh Return: AH = termination type 00h normal (INT 20,INT 21/AH=00h, or INT 21/AH=4Ch) 01h control-C abort 02h critical error abort 03h terminate and stay resident (INT 21/AH=31h or INT 27) AL = return code Notes: the word in which DOS stores the return code is cleared after being read by this function, so the return code can only be retrieved once this call should not be used if the child was started with AX=4B04h; use AH=8Ah instead the following sequence will close a Virtual DOS Machine under OS/2 2.0: MOV AH,4Dh INT 21h HLT DB 02h,0FDh This sequence is the only way to close a specific VDM which was booted from floppy or a disk image. SeeAlso: AH=4Bh,AH=4Ch,AH=8Ah --------D-214E------------------------------- INT 21 - DOS 2+ - "FINDFIRST" - FIND FIRST MATCHING FILE AH = 4Eh AL = special flag for use by APPEND (see note below) CX = file attribute mask (see AX=4301h) (bits 0 and 5 ignored) DS:DX -> ASCIZ file specification (may include path and wildcards) Return: CF clear if successful [DTA] = FindFirst data block (see below) CF set on error AX = error code (02h,03h,12h) (see AH=59h) Notes: for search attributes other than 08h, all files with at MOST the specified combination of hidden, system, and directory attributes will be returned. Under DOS 2.x, searching for attribute 08h (volume label) will also return normal files, while under DOS 3+ only the volume label (if any) will be returned. this call also returns successfully if given the name of a character device without wildcards. DOS 2.x returns attribute 00h, size 0, and the current date and time. DOS 3+ returns attribute 40h and the current date and time. immediately after an INT 2F/AX=B711h (APPEND return found name), the name at DS:DX will be overwritten; if AL=00h on entry, the actual found pathname will be stored, otherwise, the actual found path will be prepended to the original filespec without a path. under LANtastic, this call may be used to obtain a list of a server's shared resources by searching for "\\SERVER\*.*"; a list of printer resources may be obtained by searching for "\\SERVER\@*.*" under the FlashTek X-32 DOS extender, the filespec pointer is in DS:EDX BUG: under DOS 3.x and 4.x, the second and subsequent calls to this function with a character device name (no wildcards) and search attributes which include the volume-label bit (08h) will fail unless there is an intervening DOS call which implicitly or explicity performs a directory search without the volume-label bit. Such implicit searches are performed by CREATE (AH=3Ch), OPEN (AH=3Dh), UNLINK (AH=41h), and RENAME (AH=56h) SeeAlso: AH=11h,AH=4Fh,AX=4301h,INT 2F/AX=111Bh,INT 2F/AX=B711h Format of FindFirst data block: Offset Size Description ---PC-DOS 3.10, PC-DOS 4.01, MS-DOS 3.2/3.3/5.0--- 00h BYTE drive letter (bits 0-6), remote if bit 7 set 01h 11 BYTEs search template 0Ch BYTE search attributes ---DOS 2.x (and some DOS 3.x???)--- 00h BYTE search attributes 01h BYTE drive letter 02h 11 BYTEs search template ---WILDUNIX.COM--- 00h 12 BYTEs 15-character wildcard search pattern and drive letter (packed) 0Ch BYTE search attributes ---DOS 2.x and most 3.x--- 0Dh WORD entry count within directory 0Fh DWORD pointer to DTA??? 13h WORD cluster number of start of parent directory ---PC-DOS 4.01, MS-DOS 3.2/3.3/5.0--- 0Dh WORD entry count within directory 0Fh WORD cluster number of start of parent directory 11h 4 BYTEs reserved ---all versions, documented fields--- 15h BYTE attribute of file found 16h WORD file time bits 11-15: hour bits 5-10: minute bits 0-4: seconds/2 18h WORD file date bits 9-15: year-1980 bits 5-8: month bits 0-4: day 1Ah DWORD file size 1Eh 13 BYTEs ASCIZ filename+extension --------f-214E------------------------------- INT 21 - WILDUNIX.COM internal - INSTALLATION CHECK AH = 4Eh DS:DX = 0000h:0000h Return: AH = 99h if installed Program: WILDUNIX.COM is a resident Unix-style wildcard expander by Steve Hosgood and Terry Barnaby --------D-214F------------------------------- INT 21 - DOS 2+ - "FINDNEXT" - FIND NEXT MATCHING FILE AH = 4Fh [DTA] = data block from previous FindFirst or FindNext call Return: CF clear if successful CF set on error AX = error code (12h) (see AH=59h) SeeAlso: AH=12h,AH=4Eh --------D-2150------------------------------- INT 21 - DOS 2+ internal - SET CURRENT PROCESS ID (SET PSP ADDRESS) AH = 50h BX = segment of PSP for new process Notes: DOS uses the current PSP address to determine which processes own files and memory; it corresponds to process identifiers used by other OSs under DOS 2.x, this function cannot be invoked inside an INT 28h handler without setting the Critical Error flag under DOS 3+, this function does not use any of the DOS-internal stacks and may thus be called at any time, even during another INT 21h call some Microsoft applications use segments of 0000h and FFFFh; although one should only call this function with valid PSP addresses, any program hooking it should be prepared to handle invalid addresses supported by OS/2 compatibility box this call was undocumented prior to the release of DOS 5.0 SeeAlso: AH=26h,AH=51h,AH=62h --------D-2151------------------------------- INT 21 - DOS 2+ internal - GET CURRENT PROCESS ID (GET PSP ADDRESS) AH = 51h Return: BX = segment of PSP for current process Notes: DOS uses the current PSP address to determine which processes own files and memory; it corresponds to process identifiers used by other OSs under DOS 2.x, this function cannot be invoked inside an INT 28h handler without setting the Critical Error flag under DOS 3+, this function does not use any of the DOS-internal stacks and may thus be called at any time, even during another INT 21h call supported by OS/2 compatibility box identical to the documented AH=62h this call was undocumented prior to the release of DOS 5.0 SeeAlso: AH=26h,AH=50h,AH=62h --------D-2152------------------------------- INT 21 U - DOS 2+ internal - "SYSVARS" - GET LIST OF LISTS AH = 52h Return: ES:BX -> DOS list of lists Notes: partially supported by OS/2 v1.1 compatibility box (however, most pointers are FFFFh:FFFFh, LASTDRIVE is FFh, and the NUL header "next" pointer is FFFFh:FFFFh). on return, ES points at the DOS data segment (see also INT 2F/AX=1203h) SeeAlso: INT 2F/AX=1203h Format of List of Lists: Offset Size Description -12 WORD (DOS 3.1+) sharing retry count (see AX=440Bh) -10 WORD (DOS 3.1+) sharing retry delay (see AX=440Bh) -8 DWORD (DOS 3+) pointer to current disk buffer -4 WORD (DOS 3+) pointer in DOS code segment of unread CON input when CON is read via a handle, DOS reads an entire line, and returns the requested portion, buffering the rest for the next read. 0000h indicates no unread input -2 WORD segment of first memory control block 00h DWORD pointer to first Drive Parameter Block (see AH=32h) 04h DWORD pointer to first System File Table (see below) 08h DWORD pointer to active CLOCK$ device's header (most recently loaded driver with CLOCK bit set) 0Ch DWORD pointer to active CON device's header (most recently loaded driver with STDIN bit set) ---DOS 2.x--- 10h BYTE number of logical drives in system 11h WORD maximum bytes/block of any block device 13h DWORD pointer to first disk buffer (see below) 17h 18 BYTEs actual NUL device driver header (not a pointer!) NUL is always the first device on DOS's linked list of device drivers. (see below) ---DOS 3.0--- 10h BYTE number of block devices 11h WORD maximum bytes/block of any block device 13h DWORD pointer to first disk buffer (see below) 17h DWORD pointer to array of current directory structures (see below) 1Bh BYTE value of LASTDRIVE command in CONFIG.SYS (default 5) 1Ch DWORD pointer to STRING= workspace area 20h WORD size of STRING area (the x in STRING=x from CONFIG.SYS) 22h DWORD pointer to FCB table 26h WORD the y in FCBS=x,y from CONFIG.SYS 28h 18 BYTEs actual NUL device driver header (not a pointer!) NUL is always the first device on DOS's linked list of device drivers. (see below) ---DOS 3.1-3.3--- 10h WORD maximum bytes per sector of any block device 12h DWORD pointer to first disk buffer in buffer chain (see below) 16h DWORD pointer to array of current directory structures (see below) 1Ah DWORD pointer to system FCB tables (see below) 1Eh WORD number of protected FCBs (the y in the CONFIG.SYS FCBS=x,y) 20h BYTE number of block devices installed 21h BYTE number of available drive letters (largest of 5, installed block devices, and CONFIG.SYS LASTDRIVE=). Also size of current directory structure array. 22h 18 BYTEs actual NUL device driver header (not a pointer!) NUL is always the first device on DOS's linked list of device drivers. (see below) 34h BYTE number of JOIN'ed drives ---DOS 4.x--- 10h WORD maximum bytes per sector of any block device 12h DWORD pointer to disk buffer info record (see below) 16h DWORD pointer to array of current directory structures (see below) 1Ah DWORD pointer to system FCB tables (see below) 1Eh WORD number of protected FCBs (the y in the CONFIG.SYS FCBS=x,y) (always 00h for DOS 5.0) 20h BYTE number of block devices installed 21h BYTE number of available drive letters (largest of 5, installed block devices, and CONFIG.SYS LASTDRIVE=). Also size of current directory structure array. 22h 18 BYTEs actual NUL device driver header (not a pointer!) NUL is always the first device on DOS's linked list of device drivers. (see below) 34h BYTE number of JOIN'ed drives??? 35h WORD pointer within IBMDOS code segment to list of special program names (see below) (always 0000h for DOS 5.0) 37h DWORD pointer to FAR routine for resident IFS utility functions (see below) may be called by any IFS driver which does not wish to service functions 20h or 24h-28h itself 3Bh DWORD pointer to chain of IFS (installable file system) drivers 3Fh WORD the x in BUFFERS x,y (rounded up to multiple of 30 if in EMS) 41h WORD number of lookahead buffers (the y in BUFFERS x,y) 43h BYTE boot drive (1=A:) 44h BYTE 01h if 80386+, 00h otherwise??? 45h WORD extended memory size in K ---DOS 5.0-6.0--- 10h 39 BYTEs as for DOS 4.x (see above) 37h DWORD pointer to SETVER program list or 0000h:0000h 3Bh WORD (DOS=HIGH) offset in DOS CS of function to fix A20 control when executing special .COM format 3Dh WORD PSP of most-recently EXECed program if DOS in HMA, 0000h if low 3Fh 8 BYTEs as for DOS 4.x (see above) Format of memory control block (see also below): Offset Size Description 00h BYTE block type: 5Ah if last block in chain, otherwise 4Dh 01h WORD PSP segment of owner or 0000h if free 0006h if DR-DOS XMS UMB 0007h if DR-DOS excluded upper memory ("hole") 0008h if belongs to DOS FFFAh if 386MAX UMB control block (see AX=4402h"386MAX") FFFDh if 386MAX locked-out memory FFFEh if 386MAX UMB (immediately follows its control block) FFFFh if 386MAX 6.01 device driver 03h WORD size of memory block in paragraphs 05h 3 BYTEs unused by MS-DOS (386MAX) if locked-out block, region start/prev region end ---DOS 2.x,3.x--- 08h 8 BYTEs unused ---DOS 4+ --- 08h 8 BYTEs ASCII program name if PSP memory block or DR-DOS UMB, else garbage null-terminated if less than 8 characters Notes: the next MCB is at segment (current + size + 1) under DOS 3.1+, the first memory block is the DOS data segment, containing installable drivers, buffers, etc. Under DOS 4+ it is divided into subsegments, each with its own memory control block (see below), the first of which is at offset 0000h. for DOS 5+, blocks owned by DOS may have either "SC" or "SD" in bytes 08h and 09h. "SC" is system code or locked-out inter-UMB memory, "SD" is system data, device drivers, etc. Some versions of DR-DOS use only seven characters of the program name, placing a NUL in the eighth byte. Format of MS-DOS 5+ UMB control block: Offset Size Description 00h BYTE type: 5Ah if last block in chain, 4Dh otherwise 01h WORD first available paragraph in UMB if control block at start of UMB, 000Ah if control block at end of UMB 03h WORD length in paragraphs of following UMB or locked-out region 05h 3 BYTEs unused 08h 8 BYTEs block type name: "UMB" if start block, "SM" if end block in UMB Format of STARLITE (General Software's Embedded DOS) memory control block: Offset Size Description 00h BYTE block type: 5Ah if last block in chain, otherwise 4Dh 01h WORD PSP segment of owner, 0000h if free, 0008h if belongs to DOS 03h WORD size of memory block in paragraphs 05h BYTE unused 06h WORD segment address of next memory control block (0000h if last) 08h WORD segment address of previous memory control block or 0000h 0Ah 6 BYTEs reserved Format of DOS 4+ data segment subsegment control blocks: Offset Size Description 00h BYTE subsegment type (blocks typically appear in this order) "D" device driver "E" device driver appendage "I" IFS (Installable File System) driver "F" FILES= control block storage area (for FILES>5) "X" FCBS= control block storage area, if present "C" BUFFERS EMS workspace area (if BUFFERS /X option used) "B" BUFFERS= storage area "L" LASTDRIVE= current directory structure array storage area "S" STACKS= code and data area, if present (see below) "T" INSTALL= transient code 01h WORD paragraph of subsegment start (usually the next paragraph) 03h WORD size of subsegment in paragraphs 05h 3 BYTEs unused 08h 8 BYTEs for types "D" and "I", base name of file from which the driver was loaded (unused for other types) Format of data at start of STACKS code segment (if present): Offset Size Description 00h WORD ??? 02h WORD number of stacks (the x in STACKS=x,y) 04h WORD size of stack control block array (should be 8*x) 06h WORD size of each stack (the y in STACKS=x,y) 08h DWORD pointer to STACKS data segment 0Ch WORD offset in STACKS data segment of stack control block array 0Eh WORD offset in STACKS data segment of last element of that array 10h WORD offset in STACKS data segment of the entry in that array for the next stack to be allocated (initially same as value in 0Eh and works its way down in steps of 8 to the value in 0Ch as hardware interrupts pre-empt each other) Note: the STACKS code segment data may, if present, be located as follows: DOS 3.2: The code segment data is at a paragraph boundary fairly early in the IBMBIO segment (seen at 0070:0190h) DOS 3.3: The code segment is at a paragraph boundary in the DOS data segment, which may be determined by inspecting the segment pointers of the vectors for those of interrupts 02h, 08h-0Eh, 70h, 72-77h which have not been redirected by device drivers or TSRs. DOS 4+ Identified by sub-segment control block type "S" within the DOS data segment. SeeAlso: INT B4"STACKMAN" Format of array elements in STACKS data segment: Offset Size Description 00h BYTE status: 00h=free, 01h=in use, 03h=corrupted by overflow of higher stack. 01h BYTE not used 02h WORD previous SP 04h WORD previous SS 06h WORD ptr to word at top of stack (new value for SP). The word at the top of the stack is preset to point back to this control block. SHARE.EXE hooks (DOS 3.1-6.00): (offsets from first system file table--pointed at by ListOfLists+04h) Offset Size Description -3Ch DWORD pointer to FAR routine for ??? Note: not called by MS-DOS 3.3, set to 0000h:0000h by SHARE 3.3+ -38h DWORD pointer to FAR routine called on opening file on call, internal DOS location points at filename(see AX=5D06h) Return: CF clear if successful CF set on error AX = DOS error code (24h) (see AH=59h) Note: SHARE directly accesses DOS-internal data to get name of file just opened -34h DWORD pointer to FAR routine called on closing file ES:DI -> system file table Note: does something to every lock record for file -30h DWORD pointer to FAR routine to close all files for given computer (called by AX=5D03h) -2Ch DWORD pointer to FAR routine to close all files for given process (called by AX=5D04h) -28h DWORD pointer to FAR routine to close file by name (called by AX=5D02h) DS:SI -> DOS parameter list (see AX=5D00h) DPL's DS:DX -> name of file to close Return: CF clear if successful CF set on error AX = DOS error code (03h) (see AH=59h) -24h DWORD pointer to FAR routine to lock region of file call with BX = file handle CX:DX = starting offset SI:AX = size Return: CF set on error AL = DOS error code (21h) (see AH=59h) Note: not called if file is marked as remote -20h DWORD pointer to FAR routine to unlock region of file call with BX = file handle CX:DX = starting offset SI:AX = size Return: CF set on error AL = DOS error code (21h) (see AH=59h) Note: not called if file is marked as remote -1Ch DWORD pointer to FAR routine to check if file region is locked call with ES:DI -> system file table entry for file CX = length of region from current position in file Return: CF set if any portion of region locked AX = 0021h -18h DWORD pointer to FAR routine to get open file list entry (called by AX=5D05h) call with DS:SI -> DOS parameter list (see AX=5D00h) DPL's BX = index of sharing record DPL's CX = index of SFT in SFT chain of sharing rec Return: CF set on error or not loaded AX = DOS error code (12h) (see AH=59h) CF clear if successful ES:DI -> filename CX = number of locks owned by specified SFT BX = network machine number DX destroyed -14h DWORD pointer to FAR routine for updating FCB from SFT??? call with DS:SI -> unopened FCB ES:DI -> system file table entry Return: BL = C0h??? Note: copies following fields from SFT to FCB: starting cluster of file 0Bh 1Ah sharing record offset 33h 1Ch file attribute 04h 1Eh -10h DWORD pointer to FAR routine to get first cluster of FCB file ??? call with ES:DI -> system file table entry DS:SI -> FCB Return: CF set if SFT closed or sharing record offsets mismatched CF clear if successful BX = starting cluster number from FCB -0Ch DWORD pointer to FAR routine to close file if duplicate for process DS:SI -> system file table Return: AX = number of handle in JFT which already uses SFT Note: called during open/create of a file Note: if SFT was opened with inheritance enabled and sharing mode 111, does something to all other SFTs owned by same process which have the same file open mode and sharing record -08h DWORD pointer to FAR routine for ??? Note: closes various handles referring to file most-recently opened -04h DWORD pointer to FAR routine to update directory info in related SFT entries call with ES:DI -> system file table entry for file (see below) AX = subfunction (apply to each related SFT) 00h: update time stamp (offset 0Dh) and date stamp (offset 0Fh) 01h: update file size (offset 11h) and starting cluster (offset 0Bh). Sets last-accessed cluster fields to start of file if file never accessed 02h: as function 01h, but last-accessed fields always changed 03h: do both functions 00h and 02h Note: follows ptr at offset 2Bh in system file table entries Note: NOP if opened with no-inherit or via FCB Note: most of the above hooks (except -04h, -14h, -18h, and -3Ch) assume either that SS=DOS DS or SS=DS=DOS DS and directly access DOS-internal data Format of sharing record: Offset Size Description 00h BYTE flag 00h free block 01h allocated block FFh end marker 01h WORD size of block 03h BYTE checksum of pathname (including NUL) if sum of ASCII values is N, checksum is (N/256 + N%256) 04h WORD offset in SHARE's DS of lock record (see below) 06h DWORD pointer to start of system file table chain for file 0Ah WORD unique sequence number 0Ch var ASCIZ full pathname Format of SHARE.EXE lock record: Offset Size Description 00h WORD offset in SHARE's DS of next lock table in list 02h DWORD offset in file of start of locked region 06h DWORD offset in file of end of locked region 0Ah DWORD pointer to System File Table entry for this file 0Eh WORD PSP segment of lock's owner Format of DOS 2.x system file tables: Offset Size Description 00h DWORD pointer to next file table (offset FFFFh if last) 04h WORD number of files in this table 06h 28h bytes per file Offset Size Description 00h BYTE number of file handles referring to this file 01h BYTE file open mode (see AH=3Dh) 02h BYTE file attribute 03h BYTE drive (0 = character device, 1 = A, 2 = B, etc) 04h 11 BYTEs filename in FCB format (no path,no period,blank-padded) 0Fh WORD ??? 11h WORD ??? 13h DWORD file size??? 17h WORD file date in packed format (see AX=5700h) 19h WORD file time in packed format (see AX=5700h) 1Bh BYTE device attribute (see AX=4400h) ---character device--- 1Ch DWORD pointer to device driver ---block device--- 1Ch WORD starting cluster of file 1Eh WORD relative cluster in file of last cluster accessed ------ 20h WORD absolute cluster number of current cluster 22h WORD ??? 24h DWORD current file position??? Format of DOS 3.0 system file tables and FCB tables: Offset Size Description 00h DWORD pointer to next file table (offset FFFFh if last) 04h WORD number of files in this table 06h 38h bytes per file Offset Size Description 00h-1Eh as for DOS 3.1+ (see below) 1Fh WORD byte offset of directory entry within sector 21h 11 BYTES filename in FCB format (no path/period, blank-padded) 2Ch DWORD (SHARE.EXE) pointer to previous SFT sharing same file 30h WORD (SHARE.EXE) network machine number which opened file (Windows Enhanced mode DOSMGR uses the virtual machine ID as the machine number; see INT 2F/AX=1683h) 32h WORD PSP segment of file's owner (first three entries for AUX/CON/PRN contain segment of IO.SYS startup code) 34h WORD (SHARE.EXE) offset in SHARE code seg of share record 36h WORD ??? apparently always 0000h Format of DOS 3.1-3.3x system file tables and FCB tables: Offset Size Description 00h DWORD pointer to next file table (offset FFFFh if last) 04h WORD number of files in this table 06h 35h bytes per file Offset Size Description 00h WORD number of file handles referring to this file 02h WORD file open mode (see AH=3Dh) bit 15 set if this file opened via FCB 04h BYTE file attribute (see AX=4301h) 05h WORD device info word (see AX=4400h) bit 15 set if remote file bit 14 set means do not set file date/time on closing bit 12 set means don't inherit on EXEC bits 5-0 drive number for disk files 07h DWORD pointer to device driver header if character device else pointer to DOS Drive Parameter Block (see AH=32h) 0Bh WORD starting cluster of file 0Dh WORD file time in packed format (see AX=5700h) 0Fh WORD file date in packed format (see AX=5700h) 11h DWORD file size ---system file table--- 15h DWORD current offset in file (may be larger than size of file; INT 21/AH=42h does not check new position) ---FCB table--- 15h WORD counter for last I/O to FCB 17h WORD counter for last open of FCB (these are separate to determine the times of the latest I/O and open) --- 19h WORD relative cluster within file of last cluster accessed 1Bh WORD absolute cluster number of last cluster accessed 0000h if file never read or written??? 1Dh WORD number of sector containing directory entry 1Fh BYTE number of dir entry within sector (byte offset/32) 20h 11 BYTEs filename in FCB format (no path/period, blank-padded) 2Bh DWORD (SHARE.EXE) pointer to previous SFT sharing same file 2Fh WORD (SHARE.EXE) network machine number which opened file (Windows Enhanced mode DOSMGR uses the virtual machine ID as the machine number; see INT 2F/AX=1683h) 31h WORD PSP segment of file's owner (see AH=26h) (first three entries for AUX/CON/PRN contain segment of IO.SYS startup code) 33h WORD offset within SHARE.EXE code segment of sharing record (see above) 0000h = none Format of DOS 4.0-6.0 system file tables and FCB tables: Offset Size Description 00h DWORD pointer to next file table (offset FFFFh if last) 04h WORD number of files in this table 06h 3Bh bytes per file Offset Size Description 00h WORD number of file handles referring to this file 02h WORD file open mode (see AH=3Dh) bit 15 set if this file opened via FCB 04h BYTE file attribute (see AX=4301h) 05h WORD device info word (see AX=4400h) bit 15 set if remote file bit 14 set means do not set file date/time on closing bit 13 set if named pipe bit 12 set if no inherit bit 11 set if network spooler 07h DWORD pointer to device driver header if character device else pointer to DOS Drive Parameter Block (see AH=32h) or REDIR data 0Bh WORD starting cluster of file 0Dh WORD file time in packed format (see AX=5700h) 0Fh WORD file date in packed format (see AX=5700h) 11h DWORD file size 15h DWORD current offset in file ---local file--- 19h WORD relative cluster within file of last cluster accessed 1Bh DWORD number of sector containing directory entry 1Fh BYTE number of dir entry within sector (byte offset/32) ---network redirector--- 19h DWORD pointer to REDIRIFS record 1Dh 3 BYTEs ??? ------ 20h 11 BYTEs filename in FCB format (no path/period, blank-padded) 2Bh DWORD (SHARE.EXE) pointer to previous SFT sharing same file 2Fh WORD (SHARE.EXE) network machine number which opened file (Windows Enhanced mode DOSMGR uses the virtual machine ID as the machine number; see INT 2F/AX=1683h) 31h WORD PSP segment of file's owner (see AH=26h) (first three entries for AUX/CON/PRN contain segment of IO.SYS startup code) 33h WORD offset within SHARE.EXE code segment of sharing record (see above) 0000h = none 35h WORD (local) absolute cluster number of last clustr accessed (redirector) ??? 37h DWORD pointer to IFS driver for file, 0000000h if native DOS Format of current directory structure (CDS) (array, LASTDRIVE entries): Offset Size Description 00h 67 BYTEs ASCIZ path in form X:\PATH (local) or \\MACH\PATH (network) 43h WORD drive attributes (see also note below and AX=5F07h) bit 15: uses network redirector \ invalid if 00, installable bit 14: physical drive / file system if 11 bit 13: JOIN'ed \ path above is true path that would be bit 12: SUBST'ed / needed if not under SUBST or JOIN bit 7: remote drive hidden from redirector's assign-list and exempt from network connection make/break commands; set for CD-ROM drives 45h DWORD pointer to Drive Parameter Block for drive (see AH=32h) ---local drives--- 49h WORD starting cluster of current directory 0000h = root, FFFFh = never accessed 4Bh WORD ??? seems to be FFFFh always 4Dh WORD ??? seems to be FFFFh always ---network drives--- 49h DWORD pointer to redirector or REDIRIFS record, or FFFFh:FFFFh (DOS 4 only) available for use by IFS driver 4Dh WORD stored user data from INT 21/AX=5F03h ------ 4Fh WORD offset in current directory path of backslash corresponding to root directory for drive this value specifies how many characters to hide from the "CHDIR" and "GETDIR" calls; normally set to 2 to hide the drive letter and colon, SUBST, JOIN, and networks change it so that only the appropriate portion of the true path is visible to the user ---DOS 4+ --- 51h BYTE (DOS 4 only, remote drives) device type 04h network drive 52h DWORD pointer to IFS driver (DOS 4) or redirector block (DOS 5+) for this drive, 00000000h if native DOS 56h WORD available for use by IFS driver Notes: the path for invalid drives is normally set to X:\, but may be empty after JOIN x: /D in DR-DOS 5.0 or NET USE x: /D in older LAN versions normally, only one of bits 13&12 may be set together with bit 14, but DR-DOS 5.0 uses other combinations for bits 15-12: 0111 JOIN, 0001 SUBST, 0101 ASSIGN (see below) Format of DR-DOS 5.0-6.0 current directory structure entry (array): Offset Size Description 00h 67 BYTEs ASCIZ pathname of actual root directory for this logical drive 43h WORD drive attributes 1000h SUBSTed drive 3000h??? JOINed drive 4000h physical drive 5000h ASSIGNed drive 7000h JOINed drive 8000h network drive 45h BYTE physical drive number (0=A:) if this logical drive is valid 46h BYTE ??? apparently flags for JOIN and ASSIGN 47h WORD cluster number of start of parent directory (0000h = root) 49h WORD entry number of current directory in parent directory 4Bh WORD cluster number of start of current directory 4Dh WORD used for media change detection (details not available) 4Fh WORD cluster number of SUBST/JOIN "root" directory 0000h if physical root directory Format of device driver header: Offset Size Description 00h DWORD pointer to next driver, offset=FFFFh if last driver 04h WORD device attributes Character device: bit 15 set (indicates character device) bit 14 IOCTL supported (see AH=44h) bit 13 (DOS 3+) output until busy supported bit 12 reserved bit 11 (DOS 3+) OPEN/CLOSE/RemMedia calls supported bits 10-8 reserved bit 7 (DOS 5+) Generic IOCTL check call supported (cmd 19h) (see AX=4410h,AX=4411h) bit 6 (DOS 3.2+) Generic IOCTL call supported (command 13h) (see AX=440Ch,AX=440Dh) bit 5 reserved bit 4 device is special (use INT 29 "fast console output") bit 3 device is CLOCK$ (all reads/writes use transfer record described below) bit 2 device is NUL bit 1 device is standard output bit 0 device is standard input Block device: bit 15 clear (indicates block device) bit 14 IOCTL supported bit 13 non-IBM format bit 12 reserved bit 11 (DOS 3+) OPEN/CLOSE/RemMedia calls supported bit 10 reserved bit 9 direct I/O not allowed??? (set by DOS 3.3 DRIVER.SYS for "new" drives) bit 8 ??? set by DOS 3.3 DRIVER.SYS for "new" drives bit 7 (DOS 5+) Generic IOCTL check call supported (cmd 19h) (see AX=4410h,AX=4411h) bit 6 (DOS 3.2+) Generic IOCTL call supported (command 13h) implies support for commands 17h and 18h (see AX=440Ch,AX=440Dh,AX=440Eh,AX=440Fh) bits 5-2 reserved bit 1 driver supports 32-bit sector addressing (DOS 3.31+) bit 0 reserved Note: for European MS-DOS 4.0, bit 11 also indicates that bits 8-6 contain a version code (000 = DOS 3.0,3.1; 001 = DOS 3.2, 010 = European DOS 4.0) 06h WORD device strategy entry point call with ES:BX -> request header (see INT 2F/AX=0802h) 08h WORD device interrupt entry point ---character device--- 0Ah 8 BYTEs blank-padded character device name ---block device--- 0Ah BYTE number of subunits (drives) supported by driver 0Bh 7 BYTEs unused --- 12h WORD (CD-ROM driver) reserved, must be 0000h appears to be another device chain 14h BYTE (CD-ROM driver) drive letter (must initially be 00h) 15h BYTE (CD-ROM driver) number of units 16h 6 BYTEs (CD-ROM driver) signature 'MSCDnn' where 'nn' is version (currently '00') Format of CLOCK$ transfer record: Offset Size Description 00h WORD number of days since 1-Jan-1980 02h BYTE minutes 03h BYTE hours 04h BYTE hundredths of second 05h BYTE seconds Format of DOS 2.x disk buffer: Offset Size Description 00h DWORD pointer to next disk buffer, offset = FFFFh if last least-recently used buffer is first in chain 04h BYTE drive (0=A, 1=B, etc), FFh if not in use 05h 3 BYTEs unused??? (seems always to be 00h 00h 01h) 08h WORD logical sector number 0Ah BYTE number of copies to write (1 for non-FAT sectors) 0Bh BYTE sector offset between copies if multiple copies to be written 0Ch DWORD pointer to DOS Drive Parameter Block (see AH=32h) 10h buffered data Format of DOS 3.x disk buffer: Offset Size Description 00h DWORD pointer to next disk buffer, offset = FFFFh if last least-recently used buffer is first in chain 04h BYTE drive (0=A,1=B, etc), FFh if not in use 05h BYTE flags bit 7: ??? bit 6: buffer dirty bit 5: buffer has been referenced bit 4: ??? bit 3: sector in data area bit 2: sector in a directory, either root or subdirectory bit 1: sector in FAT bit 0: boot sector??? (guess) 06h WORD logical sector number 08h BYTE number of copies to write (1 for non-FAT sectors) 09h BYTE sector offset between copies if multiple copies to be written 0Ah DWORD pointer to DOS Drive Parameter Block (see AH=32h) 0Eh WORD unused??? (almost always 0) 10h buffered data Format of DOS 4.00 (pre UR 25066) disk buffer info: Offset Size Description 00h DWORD pointer to array of disk buffer hash chain heads (see below) 04h WORD number of disk buffer hash chains (referred to as NDBCH below) 06h DWORD pointer to lookahead buffer, zero if not present 0Ah WORD number of lookahead sectors, else zero (the y in BUFFERS=x,y) 0Ch BYTE 00h if buffers in EMS (/X), FFh if not 0Dh WORD EMS handle for buffers, zero if not in EMS 0Fh WORD EMS physical page number used for buffers (usually 255) 11h WORD ??? seems always to be 0001h 13h WORD segment of EMS physical page frame 15h WORD ??? seems always to be zero 17h 4 WORDs EMS partial page mapping information??? Format of DOS 4.01 (from UR 25066 Corrctive Services Disk on) disk buffer info: Offset Size Description 00h DWORD pointer to array of disk buffer hash chain heads (see below) 04h WORD number of disk buffer hash chains (referred to as NDBCH below) 06h DWORD pointer to lookahead buffer, zero if not present 0Ah WORD number of lookahead sectors, else zero (the y in BUFFERS=x,y) 0Ch BYTE 01h, possibly to distinguish from pre-UR 25066 format 0Dh WORD ??? EMS segment for BUFFERS (only with /XD) 0Fh WORD ??? EMS physical page number of EMS seg above (only with /XD) 11h WORD ??? EMS segment for ??? (only with /XD) 13h WORD ??? EMS physical page number of above (only with /XD) 15h BYTE ??? number of EMS page frames present (only with /XD) 16h WORD segment of one-sector workspace buffer allocated in main memory if BUFFERS/XS or /XD options in effect, possibly to avoid DMA into EMS 18h WORD EMS handle for buffers, zero if not in EMS 1Ah WORD EMS physical page number used for buffers (usually 255) 1Ch WORD ??? appears always to be 0001h 1Eh WORD segment of EMS physical page frame 20h WORD ??? appears always to be zero 22h BYTE 00h if /XS, 01h if /XD, FFh if BUFFERS not in EMS Format of DOS 4.x disk buffer hash chain head (array, one entry per chain): Offset Size Description 00h WORD EMS logical page number in which chain is resident, -1 if not in EMS 02h DWORD pointer to least recently used buffer header. All buffers on this chain are in the same segment. 06h BYTE number of dirty buffers on this chain 07h BYTE reserved (00h) Notes: buffered disk sectors are assigned to chain N where N is the sector's address modulo NDBCH, 0 <= N <= NDBCH-1 each chain resides completely within one EMS page this structure is in main memory even if buffers are in EMS Format of DOS 4.0-6.0 disk buffer: Offset Size Description 00h WORD forward ptr, offset only, to next least recently used buffer 02h WORD backward ptr, offset only 04h BYTE drive (0=A,1=B, etc), FFh if not in use 05h BYTE flags bit 7: remote buffer bit 6: buffer dirty bit 5: buffer has been referenced bit 4: search data buffer (only valid if remote buffer) bit 3: sector in data area bit 2: sector in a directory, either root or subdirectory bit 1: sector in FAT bit 0: reserved 06h DWORD logical sector number 0Ah BYTE number of copies to write for FAT sectors, same as number of FATs for data and directory sectors, usually 1 0Bh WORD offset in sectors between copies to write for FAT sectors 0Dh DWORD pointer to DOS Drive Parameter Block (see AH=32h) 11h WORD buffer use count if remote buffer (see flags above) 13h BYTE reserved 14h buffered data Note: for DOS 4.x, all buffered sectors which have the same hash value (computed as the sum of high and low words of the logical sector number divided by NDBCH) are on the same doubly-linked circular chain; for DOS 5+, only a single circular chain exists. the links consist of offset addresses only, the segment being the same for all buffers in the chain. Format of DOS 5.0-6.0 disk buffer info: Offset Size Description 00h DWORD pointer to least-recently-used buffer header (may be in HMA) (see above) 04h WORD 0000h (DOS 5 does not hash disk buffers, so offset 00h points directly at the only buffer chain) 06h DWORD pointer to lookahead buffer, zero if not present 0Ah WORD number of lookahead sectors, else zero (the y in BUFFERS=x,y) 0Ch BYTE buffer location 00h base memory, no workspace buffer 01h HMA, workspace buffer in base memory 0Dh DWORD pointer to one-segment workspace buffer in base memory 11h 3 BYTEs unused??? 14h WORD ??? 16h BYTE ??? counter or flag 17h BYTE temp storage for user memory allocation strategy during EXEC 18h BYTE ??? counter 19h BYTE bit flags bit 0: ??? bit 1: SWITCHES=/W specified in CONFIG.SYS (don't load WINA20.SYS when MS Windows 3.0 starts) bit 2: in EXEC state (INT 21/AX=4B05h) 1Ah WORD ??? offset of ??? (used only during INT 21/AX=4B05h) 1Ch BYTE bit 0 set iff UMB MCB chain linked to normal MCB chain 1Dh WORD minimum paragraphs of memory required by program being EXECed 1Fh WORD segment of first MCB in upper memory blocks or FFFFh if DOS memory chain in base 640K only (first UMB MCB usually at 9FFFh, locking out video memory with a DOS-owned memory block) 21h WORD paragraph of start of most recent MCB chain search Format of IFS driver list: Offset Size Description 00h DWORD pointer to next driver header 04h 8 BYTEs IFS driver name (blank padded), as used by FILESYS command 0Ch 4 BYTEs ??? 10h DWORD pointer to IFS utility function entry point (see below) call with ES:BX -> IFS request (see below) 14h WORD offset in header's segment of driver entry point ??? Call IFS utility function entry point with: AH = 20h miscellaneous functions AL = 00h get date Return: CX = year DH = month DL = day AL = 01h get process ID and computer ID Return: BX = current PSP segment DX = active network machine number AL = 05h get file system info ES:DI -> 16-byte info buffer Return: buffer filled Offset Size Description 00h 2 BYTEs unused 02h WORD number of SFTs (actually counts only the first two file table arrays) 04h WORD number of FCB table entries 06h WORD number of proctected FCBs 08h 6 BYTEs unused 0Eh WORD largest sector size supported AL = 06h get machine name ES:DI -> 18-byte buffer for name Return: buffer filled with name starting at offset 02h AL = 08h get sharing retry count Return: BX = sharing retry count AL = other Return: CF set AH = 21h get redirection state BH = type (03h disk, 04h printer) Return: BH = state (00h off, 01h on) AH = 22h ??? some sort of time calculation AL = 00h ??? nonzero ??? AH = 23h ??? some sort of time calculation AH = 24h compare filenames DS:SI -> first ASCIZ filename ES:DI -> second ASCIZ filename Return: ZF set if files are same ignoring case and / vs \ AH = 25h normalize filename DS:SI -> ASCIZ filename ES:DI -> buffer for result Return: filename uppercased, forward slashes changed to backslashes AH = 26h get DOS stack Return: DS:SI -> top of stack CX = size of stack in bytes AH = 27h increment InDOS flag AH = 28h decrement InDOS flag Note: IFS drivers which do not wish to implement functions 20h or 24h-28h may pass them on to the default handler pointed at by [LoL+37h] Format of IFS request block: Offset Size Description 00h WORD total size in bytes of request 02h BYTE class of request 02h ??? 03h redirection 04h ??? 05h file access 06h convert error code to string 07h ??? 03h WORD returned DOS error code 05h BYTE IFS driver exit status 00h success 01h ??? 02h ??? 03h ??? 04h ??? FFh internal failure 06h 16 BYTEs ??? ---request class 02h--- 16h BYTE function code 04h ??? 17h BYTE unused??? 18h DWORD pointer to ??? 1Ch DWORD pointer to ??? 20h 2 BYTEs ??? ---request class 03h--- 16h BYTE function code 17h BYTE ??? 18h DWORD pointer to ??? 1Ch DWORD pointer to ??? 22h WORD returned ??? 24h WORD returned ??? 26h WORD returned ??? 28h BYTE returned ??? 29h BYTE unused??? ---request class 04h--- 16h DWORD pointer to ??? 1Ah DWORD pointer to ??? ---request class 05h--- 16h BYTE function code 01h flush disk buffers 02h get disk space 03h MKDIR 04h RMDIR 05h CHDIR 06h delete file 07h rename file 08h search directory 09h file open/create 0Ah LSEEK 0Bh read from file 0Ch write to file 0Dh lock region of file 0Eh commit/close file 0Fh get/set file attributes 10h printer control 11h ??? 12h process termination 13h ??? ---class 05h function 01h--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h 4 BYTEs ??? 26h BYTE ??? 27h BYTE ??? ---class 05h function 02h--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h 4 BYTEs ??? 26h WORD returned total clusters 28h WORD returned sectors per cluster 2Ah WORD returned bytes per sector 2Ch WORD returned available clusters 2Eh BYTE returned ??? 2Fh BYTE ??? ---class 05h functions 03h,04h,05h--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h 4 BYTEs ??? 26h DWORD pointer to directory name ---class 05h function 06h--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h 4 BYTEs ??? 26h WORD attribute mask 28h DWORD pointer to filename ---class 05h function 07h--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h 4 BYTEs ??? 26h WORD attribute mask 28h DWORD pointer to source filespec 2Ch DWORD pointer to destination filespec ---class 05h function 08h--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h 4 BYTEs ??? 26h BYTE 00h FINDFIRST 01h FINDNEXT 28h DWORD pointer to FindFirst search data + 01h if FINDNEXT 2Ch WORD search attribute if FINDFIRST 2Eh DWORD pointer to filespec if FINDFIRST ---class 05h function 09h--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h DWORD pointer to IFS open file structure (see below) 26h WORD ??? \ together, specify open vs. create, whether or 28h WORD ??? / not to truncate 2Ah 4 BYTEs ??? 2Eh DWORD pointer to filename 32h 4 BYTEs ??? 36h WORD file attributes on call returned ??? 38h WORD returned ??? ---class 05h function 0Ah--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h DWORD pointer to IFS open file structure (see below) 26h BYTE seek type (02h = from end) 28h DWORD offset on call returned new absolute position ---class 05h functions 0Bh,0Ch--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h DWORD pointer to IFS open file structure (see below) 28h WORD number of bytes to transfer returned bytes actually transferred 2Ah DWORD transfer address ---class 05h function 0Dh--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h DWORD pointer to IFS open file structure (see below) 26h BYTE file handle??? 27h BYTE unused??? 28h WORD ??? 2Ah WORD ??? 2Ch WORD ??? 2Eh WORD ??? ---class 05h function 0Eh--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h DWORD pointer to IFS open file structure (see below) 26h BYTE 00h commit file 01h close file 27h BYTE unused??? ---class 05h function 0Fh--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h 4 BYTEs ??? 26h BYTE 02h GET attributes 03h PUT attributes 27h BYTE unused??? 28h 12 BYTEs ??? 34h WORD search attributes??? 36h DWORD pointer to filename 3Ah WORD (GET) returned ??? 3Ch WORD (GET) returned ??? 3Eh WORD (GET) returned ??? 40h WORD (GET) returned ??? 42h WORD (PUT) new attributes (GET) returned attributes ---class 05h function 10h--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h DWORD pointer to IFS open file structure (see below) 26h WORD ??? 28h DWORD pointer to ??? 2Ch WORD ??? 2Eh BYTE ??? 2Fh BYTE subfunction 01h get printer setup 03h ??? 04h ??? 05h ??? 06h ??? 07h ??? 21h set printer setup ---class 05h function 11h--- 17h 7 BYTEs ??? 1Eh DWORD pointer to ??? 22h DWORD pointer to IFS open file structure (see below) 26h BYTE subfunction 27h BYTE unused??? 28h WORD ??? 2Ah WORD ??? 2Ch WORD ??? 2Eh BYTE ??? 2Fh BYTE ??? ---class 05h function 12h--- 17h 15 BYTEs unused??? 26h WORD PSP segment 28h BYTE type of process termination 29h BYTE unused??? ---class 05h function 13h--- 17h 15 BYTEs unused??? 26h WORD PSP segment ---request class 06h--- 16h DWORD returned pointer to string corresponding to error code at 03h 1Ah BYTE returned ??? 1Bh BYTE unused ---request class 07h--- 16h DWORD pointer to IFS open file structure (see below) 1Ah BYTE ??? 1Bh BYTE unused??? Format of IFS open file structure: Offset Size Description 00h WORD ??? 02h WORD device info word 04h WORD file open mode 06h WORD ??? 08h WORD file attributes 0Ah WORD owner's network machine number 0Ch WORD owner's PSP segment 0Eh DWORD file size 12h DWORD current offset in file 16h WORD file time 18h WORD file date 1Ah 11 BYTEs filename in FCB format 25h WORD ??? 27h WORD hash value of SFT address (low word of linear address + segment&F000h) 29h 3 WORDs network info from SFT 2Fh WORD ??? Format of one item in DOS 4+ list of special program names: Offset Size Description 00h BYTE length of name (00h = end of list) 01h N BYTEs name in format name.ext N 2 BYTEs DOS version to return for program (major,minor) (see AH=30h,INT 2F/AX=122Fh) ---DOS 4 only--- N+2 BYTE number of times to return fake version number (FFh = always) Note: if the name of the executable for the program making the DOS "get version" call matches one of the names in this list, DOS returns the specified version rather than the true version number --------v-215252----------------------------- INT 21 - VIRUS - "516"/"Leapfrog" - INSTALLATION CHECK AX = 5252h Return: BX = FFEEh if resident SeeAlso: AX=4BFFh"Cascade",AX=58CCh --------D-2153------------------------------- INT 21 - DOS 2+ internal - TRANSLATE BIOS PARAMETER BLOCK TO DRIVE PARAM BLOCK AH = 53h DS:SI -> BIOS Parameter Block (see below) ES:BP -> buffer for Drive Parameter Block (see AH=32h for format) Return: ES:BP buffer filled Note: for DOS 3+, the cluster at which to start searching is set to 0000h and the number of free clusters is set to FFFFh (unknown) Format of BIOS Parameter Block: Offset Size Description 00h WORD number of bytes per sector 02h BYTE number of sectors per cluster 03h WORD number of reserved sectors at start of disk 05h BYTE number of FATs 06h WORD number of entries in root directory 08h WORD total number of sectors for DOS 4+, set to zero if partition >32M, then set DWORD at 15h to actual number of sectors 0Ah BYTE media ID byte 0Bh WORD number of sectors per FAT ---DOS 3+--- 0Dh WORD number of sectors per track 0Fh WORD number of heads 11h DWORD number of hidden sectors 15h 11 BYTEs reserved ---DOS 4+ --- 15h DWORD total number of sectors if word at 08h contains zero 19h 6 BYTEs ??? 1Fh WORD number of cylinders 21h BYTE device type 22h WORD device attributes (removable or not, etc) ---European MS-DOS 4.00--- 15h DWORD total number of sectors if word at 08h contains zero (however, this DOS does not actually implement >32M partitions) --------D-2154------------------------------- INT 21 - DOS 2+ - GET VERIFY FLAG AH = 54h Return: AL = verify flag 00h off 01h on (all disk writes verified after writing) SeeAlso: AH=2Eh --------D-2155------------------------------- INT 21 - DOS 2+ internal - CREATE CHILD PSP AH = 55h DX = segment at which to create new PSP SI = (DOS 3+) value to place in memory size field at DX:[0002h] Return: CF clear if successful Notes: creates a "child" PSP rather than making an exact copy of the current PSP; the new PSP's parent pointer is set to the current PSP and the reference count for each inherited file is incremented (DOS 2+) sets current PSP to DX (DOS 3+) marks "no inherit" file handles as closed in child PSP SeeAlso: AH=26h,AH=50h --------D-2156------------------------------- INT 21 - DOS 2+ - "RENAME" - RENAME FILE AH = 56h DS:DX -> ASCIZ filename of existing file (no wildcards, but see below) ES:DI -> ASCIZ new filename (no wildcards) CL = attribute mask (server call only, see below) Return: CF clear if successful CF set on error AX = error code (02h,03h,05h,11h) (see AH=59h) Notes: allows move between directories on same logical volume does not set the archive attribute (see AX=4300h), which results in incremental backups not backing up the file under its new name open files should not be renamed (DOS 3+) allows renaming of directories (DOS 3.1+) wildcards are allowed if invoked via AX=5D00h, in which case error 12h (no more files) is returned on success, and both source and destination specs must be canonical (as returned by AH=60h). Wildcards in the destination are replaced by the corresponding char of each source file being renamed. Under DOS 3.x, the call will fail if the destination wildcard is *.* or equivalent. When invoked via AX=5D00h, only those files matching the attribute mask in CL are renamed. under the FlashTek X-32 DOS extender, the old-name pointer is in DS:EDX and the new-name pointer is in ES:EDI (DS must equal ES) SeeAlso: AH=17h,AX=4301h,AH=60h,AX=5D00h --------D-215700----------------------------- INT 21 - DOS 2+ - GET FILE'S DATE AND TIME AX = 5700h BX = file handle Return: CF clear if successful CX = file's time bits 15-11: hours (0-23) 10-5: minutes 4-0: seconds/2 DX = file's date bits 15-9: year - 1980 8-5: month 4-0: day CF set on error AX = error code (01h,06h) (see AH=59h) SeeAlso: AX=5701h --------D-215701----------------------------- INT 21 - DOS 2+ - SET FILE'S DATE AND TIME AX = 5701h BX = file handle CX = new time (see AX=5700h) DX = new date (see AX=5700h) Return: CF clear if successful CF set on error AX = error code (01h,06h) (see AH=59h) SeeAlso: AX=5700h --------D-215702----------------------------- INT 21 - DOS 4.x only - GET ??? AX = 5702h BX = ??? (0000h through 0004h) DS:SI -> ??? ES:DI -> result buffer CX = size of result buffer Return: CX = size of returned data SeeAlso: AX=5703h,AX=5704h --------D-215703----------------------------- INT 21 - DOS 4.x only - GET ??? AX = 5703h BX = file handle (only 0000h through 0004h valid) DS:SI -> ??? passed through to INT 2F/AX=112Dh ES:DI -> result buffer CX = size of result buffer Return: CX = size of returned data ES:DI -> zero word (DOS 4.0) if CX >= 2 on entry SeeAlso: AX=5702h,AX=5704h,INT 2F/AX=112Dh --------D-215704----------------------------- INT 21 - DOS 4.x only - TRUNCATE OPEN FILE TO ZERO LENGTH AX = 5704h BX = file handle (only 0000h through 0004h valid) DS:SI -> ??? passed through to INT 2F/AX=112Dh ES:DI -> result buffer CX = size of result buffer Return: CX = size of returned data ES:DI -> zero word (DOS 4.0) if CX >= 2 on entry SeeAlso: AX=5702h,AX=5703h,INT 2F/AX=112Dh --------D-2158------------------------------- INT 21 - DOS 3+ - GET OR SET MEMORY ALLOCATION STRATEGY AH = 58h AL = subfunction 00h get allocation strategy Return: AX = current strategy 00h low memory first fit 01h low memory best fit 02h low memory last fit ---DOS 5+ --- 40h high memory first fit 41h high memory best fit 42h high memory last fit 80h first fit, try high then low memory 81h best fit, try high then low memory 82h last fit, try high then low memory 01h set allocation strategy BL = new allocation strategy (see above) BH = 00h (DOS 5+) Return: CF clear if successful CF set on error AX = error code (01h) (see AH=59h) Notes: the Set subfunction accepts any value in BL for DOS 3.x and 4.x; 2 or greater means last fit the Get subfunction returns the last value set setting an allocation strategy involving high memory does not automatically link in the UMB memory chain; this must be done explicitly with AX=5803h in order to actually allocate high memory a program which changes the allocation strategy should restore it before terminating Toshiba MS-DOS 2.11 supports subfunctions 00h and 01h DR-DOS 3.41 reportedly reverses subfunctions 00h and 01h SeeAlso: AH=48h,AH=49h,AH=4Ah,INT 2F/AX=4310h,INT 67/AH=3Fh --------D-2158------------------------------- INT 21 - DOS 5+ - GET OR SET UMB LINK STATE AH = 58h AL = subfunction 02h get UMB link state Return: AL = 00h UMBs not part of DOS memory chain = 01h UMBs in DOS memory chain 03h set UMB link state BX = 0000h remove UMBs from DOS memory chain = 0001h add UMBs to DOS memory chain Return: CF clear if successful CF set on error AX = error code (01h) (see AH=59h) Note: a program which changes the UMB link state should restore it before terminating --------v-2158CC----------------------------- INT 21 - VIRUS - "1067"/"Headcrash" - INSTALLATION CHECK AX = 58CCh Return: CF clear if resident SeeAlso: AX=5252h,AX=6969h --------D-2159--BX0000----------------------- INT 21 - DOS 3+ - GET EXTENDED ERROR INFORMATION AH = 59h BX = 0000h Return: AX = extended error code (see below) BH = error class (see below) BL = recommended action (see below) CH = error locus (see below) ES:DI may be pointer (see error code list below) CL, DX, SI, BP, and DS destroyed Notes: functions available under DOS 2.x map the true DOS 3+ error code into one supported under DOS 2.x you should call this function to retrieve the true error code when an FCB or DOS 2.x call returns an error under DR-DOS 5.0, this function does not use any of the DOS-internal stacks and may thus be called at any time SeeAlso: AX=5D0Ah,INT 2F/AX=122Dh Values for extended error code: 00h no error 01h function number invalid 02h file not found 03h path not found 04h too many open files (no handles available) 05h access denied 06h invalid handle 07h memory control block destroyed 08h insufficient memory 09h memory block address invalid 0Ah environment invalid (usually >32K in length) 0Bh format invalid 0Ch access code invalid 0Dh data invalid 0Eh reserved 0Fh invalid drive 10h attempted to remove current directory 11h not same device 12h no more files ---DOS 3+--- 13h disk write-protected 14h unknown unit 15h drive not ready 16h unknown command 17h data error (CRC) 18h bad request structure length 19h seek error 1Ah unknown media type (non-DOS disk) 1Bh sector not found 1Ch printer out of paper 1Dh write fault 1Eh read fault 1Fh general failure 20h sharing violation 21h lock violation 22h disk change invalid ES:DI -> ASCIZ volume label of required disk 23h FCB unavailable 24h sharing buffer overflow 25h (DOS 4+) code page mismatch 26h (DOS 4+) cannot complete file operation (out of input) 27h (DOS 4+) insufficient disk space 28h-31h reserved 32h network request not supported 33h remote computer not listening 34h duplicate name on network 35h network name not found 36h network busy 37h network device no longer exists 38h network BIOS command limit exceeded 39h network adapter hardware error 3Ah incorrect response from network 3Bh unexpected network error 3Ch incompatible remote adapter 3Dh print queue full 3Eh queue not full 3Fh not enough space to print file 40h network name was deleted 41h network: Access denied 42h network device type incorrect 43h network name not found 44h network name limit exceeded 45h network BIOS session limit exceeded 46h temporarily paused 47h network request not accepted 48h network print/disk redirection paused 49h network software not installed (LANtastic) invalid network version 4Ah unexpected adapter close (LANtastic) account expired 4Bh (LANtastic) password expired 4Ch (LANtastic) login attempt invalid at this time 4Dh (LANtastic v3+) disk limit exceeded on network node 4Eh (LANtastic v3+) not logged in to network node 4Fh reserved 50h file exists 51h reserved 52h cannot make directory 53h fail on INT 24h 54h (DOS 3.3+) too many redirections 55h (DOS 3.3+) duplicate redirection 56h (DOS 3.3+) invalid password 57h (DOS 3.3+) invalid parameter 58h (DOS 3.3+) network write fault 59h (DOS 4+) function not supported on network 5Ah (DOS 4+) required system component not installed 64h (MSCDEX) unknown error 65h (MSCDEX) not ready 66h (MSCDEX) EMS memory no longer valid 67h (MSCDEX) not High Sierra or ISO-9660 format 68h (MSCDEX) door open Values for Error Class: 01h out of resource (storage space or I/O channels) 02h temporary situation (file or record lock) 03h authorization (denied access) 04h internal (system software bug) 05h hardware failure 06h system failure (configuration file missing or incorrect) 07h application program error 08h not found 09h bad format 0Ah locked 0Bh media error 0Ch already exists 0Dh unknown Values for Suggested Action: 01h retry 02h delayed retry 03h prompt user to reenter input 04h abort after cleanup 05h immediate abort 06h ignore 07h retry after user intervention Values for Error Locus: 01h unknown or not appropriate 02h block device (disk error) 03h network related 04h serial device (timeout) 05h memory related --------D-2159--BX0001----------------------- INT 21 - European MS-DOS 4.0 - GET HARD ERROR INFORMATION AH = 59h BX = 0001h Return: ES:DI -> hard error information packet (see below) for most recent hard (critical) error SeeAlso: AH=95h,INT 24 Format of hard error information packet: Offset Size Description 00h WORD contents of AX at system entry 02h WORD Process ID which encountered error 04h WORD contents of AX at time of error 06h BYTE error type 00h physical I/O error 01h disk change request 02h file sharing violation 03h FCB problem 04h file locking violation 05h bad FAT 06h network detected error 07h BYTE INT 24 error code 08h WORD extended error code (see AH=59h/BX=0000h) 0Ah DWORD pointer to associated device --------D-215A------------------------------- INT 21 - DOS 3+ - CREATE TEMPORARY FILE AH = 5Ah CX = file attribute (see AX=4301h) DS:DX -> ASCIZ path ending with a '\' + 13 zero bytes to receive the generated filename Return: CF clear if successful AX = file handle opened for read/write in compatibility mode DS:DX pathname extended with generated name for temporary file CF set on error AX = error code (03h,04h,05h) (see AH=59h) Desc: creates a file with a unique name which must be explicitly deleted Notes: COMPAQ DOS 3.31 hangs if the pathname is at XXXXh:0000h; it apparently wraps around to the end of the segment under the FlashTek X-32 DOS extender, the path pointer is in DS:EDX SeeAlso: AH=3Ch,AH=5Bh --------D-215B------------------------------- INT 21 - DOS 3+ - CREATE NEW FILE AH = 5Bh CX = file attribute (see AX=4301h) DS:DX -> ASCIZ filename Return: CF clear if successful AX = file handle opened for read/write in compatibility mode CF set on error AX = error code (03h,04h,05h,50h) (see AH=59h) Notes: unlike AH=3Ch, this function will fail if the specified file exists rather than truncating it; this permits its use in creating semaphore files because it is an atomic "test and set" operation under the FlashTek X-32 DOS extender, the filename pointer is in DS:EDX SeeAlso: AH=3Ch,AH=5Ah --------D-215C------------------------------- INT 21 - DOS 3+ - "FLOCK" - RECORD LOCKING AH = 5Ch AL = subfunction 00h lock region of file 01h unlock region of file BX = file handle CX:DX = start offset of region within file SI:DI = length of region in bytes Return: CF clear if successful CF set on error AX = error code (01h,06h,21h,24h) (see AH=59h) Notes: error returned unless SHARE or network installed an unlock call must specify the same region as some prior lock call locked regions become entirely inaccessible to other processes duplicate handles created with AH=45h or AH=46h inherit locks, but handles inherited by child processes (see AH=4Bh) do not SeeAlso: AX=440Bh,AH=BCh,AH=BEh,INT 2F/AX=110Ah,INT 2F/AX=110Bh --------D-215D00----------------------------- INT 21 U - DOS 3.1+ internal - SERVER FUNCTION CALL AX = 5D00h DS:DX -> DOS parameter list (see below) DPL contains all register values for a call to INT 21h Return: as appropriate for function being called Notes: does not check AH. Out of range values will crash the system executes using specified computer ID and process ID sharing delay loops skipped a special sharing mode is enabled wildcards are enabled for DELETE (AH=41h) and RENAME (AH=56h) an extra file attribute parameter is enabled for OPEN (AH=3Dh), DELETE (AH=41h), and RENAME (AH=56h) functions which take filenames require canonical names (as returned by AH=60h); this is apparently to prevent multi-hop file forwarding SeeAlso: AH=3Dh,AH=41h,AH=56h,AH=60h Format of DOS parameter list: Offset Size Description 00h WORD AX 02h WORD BX 04h WORD CX 06h WORD DX 08h WORD SI 0Ah WORD DI 0Ch WORD DS 0Eh WORD ES 10h WORD reserved (0) 12h WORD computer ID (0 = current system) 14h WORD process ID (PSP segment on specified computer) Note: under Windows Enhanced mode, the computer ID is normally the virtual machine ID (see INT 2F/AX=1683h), though this can reportedly be changed by setting UniqueDOSPSP= in SYSTEM.INI --------D-215D01----------------------------- INT 21 U - DOS 3.1+ internal - COMMIT ALL FILES FOR SPECIFIED COMPUTER/PROCESS AX = 5D01h DS:DX -> DOS parameter list (see AX=5D00h), only computer ID and process ID fields used Return: CF set on error AX = error code (see AH=59h) CF clear if successful Notes: flushes buffers and updates directory entries for each file which has been written to; if remote file, calls INT 2F/AX=1107h the computer ID and process ID are stored but ignored under DOS 3.3 SeeAlso: AH=0Dh,AH=68h,INT 2F/AX=1107h --------D-215D02----------------------------- INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE FILE BY NAME AX = 5D02h DS:DX -> DOS parameter list (see AX=5D00h), only fields DX, DS, computer ID, and process ID used DPL's DS:DX -> ASCIZ name of file to close Return: CF set on error AX = error code (see AH=59h) CF clear if successful Notes: error unless SHARE is loaded (calls [SysFileTable-28h]) (see AH=52h) name must be canonical fully-qualified, such as returned by AH=60h SeeAlso: AX=5D03h,AX=5D04h,AH=3Eh,AH=60h --------D-215D03----------------------------- INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE ALL FILES FOR GIVEN COMPUTER AX = 5D03h DS:DX -> DOS parameter list (see AX=5D00h), only computer ID used Return: CF set on error AX = error code (see AH=59h) CF clear if successful Note: error unless SHARE is loaded (calls [SysFileTable-30h]) (see AH=52h) SeeAlso: AX=5D02h,AX=5D04h --------D-215D04----------------------------- INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE ALL FILES FOR GIVEN PROCESS AX = 5D04h DS:DX -> DOS parameter list (see AX=5D00h), only computer ID and process ID fields used Return: CF set on error AX = error code (see AH=59h) CF clear if successful Note: error unless SHARE is loaded (calls [SysFileTable-2Ch]) (see AH=52h) SeeAlso: AX=5D02h,AX=5D03h,INT 2F/AX=111Dh --------D-215D05----------------------------- INT 21 U - DOS 3.1+ internal - SHARE.EXE - GET OPEN FILE LIST ENTRY AX = 5D05h DS:DX -> DOS parameter list (see AX=5D00h) DPL's BX = index of sharing record (see AH=52h) DPL's CX = index of SFT in sharing record's SFT list Return: CF clear if successful ES:DI -> ASCIZ filename BX = network machine number of SFT's owner CX = number of locks held by SFT's owner CF set if either index out of range AX = 0012h (no more files) Notes: error unless SHARE is loaded (calls [SysFileTable-18h]) (see AH=52h) names are always canonical fully-qualified, such as returned by AH=60h SeeAlso: AH=5Ch,AH=60h --------D-215D06----------------------------- INT 21 U - DOS 3.0+ internal - GET ADDRESS OF DOS SWAPPABLE DATA AREA AX = 5D06h Return: CF set on error AX = error code (see AH=59h) CF clear if successful DS:SI -> nonreentrant data area (includes all three DOS stacks) (critical error flag is first byte) CX = size in bytes of area which must be swapped while in DOS DX = size in bytes of area which must always be swapped Notes: the Critical Error flag is used in conjunction with the InDOS flag (see AH=34h) to determine when it is safe to enter DOS from a TSR setting CritErr flag allows use of functions 50h/51h from INT 28h under DOS 2.x by forcing use of correct stack swapping the data area allows reentering DOS unless DOS is in a critical section delimited by INT 2A/AH=80h and INT 2A/AH=81h,82h under DOS 4.0, AX=5D0Bh should be used instead of this function SHARE and other DOS utilities consult the byte at offset 04h in the DOS data segment (see INT 2F/AX=1203h) to determine the SDA format in use: 00h = DOS 3.x, 01h = DOS 4.0-6.0, other = error. SeeAlso: AX=5D0Bh,INT 2A/AH=80h,INT 2A/AH=81h,INT 2A/AH=82h Format of DOS 3.10-3.30 Swappable Data Area: Offset Size Description -11 5 WORDs zero-terminated list of offsets which need to be patched to enabled critical-section calls (see INT 2A/AH=80h) (not actually part of the SDA) 00h BYTE critical error flag 01h BYTE InDOS flag (count of active INT 21 calls) 02h BYTE drive on which current critical error occurred, or FFh 03h BYTE locus of last error 04h WORD extended error code of last error 06h BYTE suggested action for last error 07h BYTE class of last error 08h DWORD ES:DI pointer for last error 0Ch DWORD current DTA 10h WORD current PSP 12h WORD stores SP across an INT 23 14h WORD return code from last process termination (zerod after reading with AH=4Dh) 16h BYTE current drive 17h BYTE extended break flag ---remainder need only be swapped if in DOS--- 18h WORD value of AX on call to INT 21 1Ah WORD PSP segment for sharing/network 1Ch WORD network machine number for sharing/network (0000h = us) 1Eh WORD first usable memory block found when allocating memory 20h WORD best usable memory block found when allocating memory 22h WORD last usable memory block found when allocating memory 24h WORD memory size in paragraphs (used only during initialization) 26h WORD ??? 28h BYTE INT 24 returned Fail 29h BYTE bit flags for allowable actions on INT 24 2Ah BYTE ??? flag 2Bh BYTE FFh if Ctrl-Break termination, 00h otherwise 2Ch BYTE ??? flag of some kind 2Dh BYTE ??? (doesn't seem to be referenced) 2Eh BYTE day of month 2Fh BYTE month 30h WORD year - 1980 32h WORD number of days since 1-1-1980 34h BYTE day of week (0 = Sunday) 35h BYTE working SFT pointer at SDA+2AAh is valid ??? 36h BYTE safe to call INT 28 if nonzero 37h BYTE flag: if nonzero, INT 24 abort turned into INT 24 fail (set only during process termination) 38h 26 BYTEs device driver request header (see INT 2F/AX=0802h) 52h DWORD pointer to device driver entry point (used in calling driver) 56h 22 BYTEs device driver request header 6Ch 22 BYTEs device driver request header 82h BYTE type of PSP copy (00h=simple for INT 21/AH=26h, FFh=make child) 83h BYTE ??? apparently not referenced by kernel 84h 3 BYTEs 24-bit user number (see AH=30h) 87h BYTE OEM number (see AH=30h) 88h 2 BYTEs ??? 8Ah 6 BYTEs CLOCK$ transfer record (see AH=52h) 90h BYTE ??? buffer for single-byte I/O functions 91h BYTE ??? apparently not referenced by kernel 92h 128 BYTEs buffer for filename 112h 128 BYTEs buffer for filename 192h 21 BYTEs findfirst/findnext search data block (see AH=4Eh) 1A7h 32 BYTEs directory entry for found file (see AH=11h) 1C7h 81 BYTEs copy of current directory structure for drive being accessed 218h 11 BYTEs FCB-format filename for device name comparison 223h BYTE unused??? 224h 11 BYTEs wildcard destination specification for rename (FCB format) 22Fh 2 BYTEs ??? 231h WORD ??? 233h 5 BYTEs ??? 238h BYTE extended FCB file attribute 239h BYTE type of FCB (00h regular, FFh extended) 23Ah BYTE directory search attributes 23Bh BYTE file open mode??? 23Ch BYTE ??? flag bits 0 and 4 23Dh BYTE ??? flag or counter 23Eh BYTE ??? flag 23Fh BYTE flag indicating how DOS function was invoked (00h = direct INT 20/INT 21, FFh = server call AX=5D00h) 240h BYTE ??? 241h BYTE ??? flag 242h BYTE flag: 00h if read, 01h if write 243h BYTE drive number for ??? 244h BYTE ??? 245h BYTE ??? flag or counter 246h BYTE line edit (AH=0Ah) insert mode flag (nonzero = on) 247h BYTE canonicalized filename referred to existing file/dir if FFh 248h BYTE ??? flag or counter 249h BYTE type of process termination (00h-03h) (see AH=4Dh) 24Ah BYTE ??? flag 24Bh BYTE value with which to replace first byte of deleted file's name (normally E5h, but 00h as described under INT 21/AH=13h) 24Ch DWORD pointer to Drive Parameter Block for critical error invocation 250h DWORD pointer to stack frame containing user registers on INT 21 254h WORD stores SP across INT 24 256h DWORD pointer to DOS Drive Parameter Block for ??? 25Ah WORD ??? 25Ch WORD ??? temp 25Eh WORD ??? flag (only low byte referenced) 260h WORD ??? temp 262h BYTE Media ID byte returned by AH=1Bh,1Ch 263h BYTE ??? (doesn't seem to be referenced) 264h DWORD pointer to device header 268h DWORD pointer to current SFT 26Ch DWORD pointer to current directory structure for drive being accessed 270h DWORD pointer to caller's FCB 274h WORD number of SFT to which file being opened will refer 276h WORD temporary storage for file handle 278h DWORD pointer to a JFT entry in process handle table (see AH=26h) 27Ch WORD offset in DOS DS of first filename argument 27Eh WORD offset in DOS DS of second filename argument 280h WORD offset of last component in pathname or FFFFh 282h WORD ??? offset of transfer address??? 284h WORD ??? relative cluster within file being accessed ??? 286h WORD ??? absolute cluster number being accessed ??? 288h WORD ??? current sector number 28Ah WORD ??? current cluster number 28Ch WORD ??? current offset in file DIV bytes per sector 28Eh 2 BYTEs ??? 290h WORD ??? current offset in file MOD bytes per sector 292h DWORD current offset in file 296h WORD ??? 298h WORD ??? 29Ah WORD ??? 29Ch WORD ??? 29Eh WORD ??? 2A0h WORD ??? 2A2h DWORD number of bytes appended to file 2A6h DWORD pointer to ??? disk buffer 2AAh DWORD pointer to working SFT 2AEh WORD used by INT 21 dispatcher to store caller's BX 2B0h WORD used by INT 21 dispatcher to store caller's DS 2B2h WORD temporary storage while saving/restoring caller's registers 2B4h DWORD pointer to prev call frame (offset 250h) if INT 21 reentered also switched to for duration of INT 24 2B8h 21 BYTEs FindFirst search data for source file(s) of a rename operation (see AH=4Eh) 2CDh 32 BYTEs directory entry for file being renamed (see AH=11h for format) 2EDh 331 BYTEs critical error stack 403h 35 BYTEs scratch SFT 438h 384 BYTEs disk stack (functions greater than 0Ch, INT 25,INT 26) 5B8h 384 BYTEs character I/O stack (functions 01h through 0Ch) ---DOS 3.2,3.3 only--- 738h BYTE device driver lookahead flag (see AH=64h) 739h BYTE ??? looks like a drive number 73Ah BYTE ??? flag of some kind 73Ah BYTE ??? --------D-215D07----------------------------- INT 21 U - DOS 3.1+ network - GET REDIRECTED PRINTER MODE AX = 5D07h Return: DL = mode 00h redirected output is combined 01h redirected output in separate print jobs SeeAlso: AX=5D08h,AX=5D09h,INT 2F/AX=1125h --------D-215D08----------------------------- INT 21 U - DOS 3.1+ network - SET REDIRECTED PRINTER MODE AX = 5D08h DL = mode 00h redirected output is combined 01h redirected output placed in separate jobs, start new print job now SeeAlso: AX=5D07h,AX=5D09h,INT 2F/AX=1125h --------D-215D09----------------------------- INT 21 U - DOS 3.1+ network - FLUSH REDIRECTED PRINTER OUTPUT AX = 5D09h Note: forces redirected printer output to be printed, and starts a new print job SeeAlso: AX=5D07h,AX=5D08h,INT 2F/AX=1125h --------D-215D0A----------------------------- INT 21 - DOS 3.1+ - SET EXTENDED ERROR INFORMATION AX = 5D0Ah DS:DX -> 11-word DOS parameter list (see AX=5D00h) Return: nothing. next call to AH=59h will return values from fields AX,BX,CX, DX,DI, and ES in corresponding registers Notes: documented for DOS 5+, but undocumented in earlier versions the MS-DOS Programmer's Reference incorrectly states that this call was introduced in DOS 4, and fails to mention that the ERROR structure passed to this function is a DOS parameter list. SeeAlso: AH=59h --------D-215D0B----------------------------- INT 21 U - DOS 4.x only internal - GET DOS SWAPPABLE DATA AREAS AX = 5D0Bh Return: CF set on error AX = error code (see AH=59h) CF clear if successful DS:SI -> swappable data area list (see below) Notes: copying and restoring the swappable data areas allows DOS to be reentered unless it is in a critical section delimited by calls to INT 2A/AH=80h and INT 2A/AH=81h,82h SHARE and other DOS utilities consult the byte at offset 04h in the DOS data segment (see INT 2F/AX=1203h) to determine the SDA format in use: 00h = DOS 3.x, 01h = DOS 4.0-6.0, other = error. SeeAlso: AX=5D06h,INT 2A/AH=80h,INT 2A/AH=81h,INT 2A/AH=82h,INT 2F/AX=1203h Format of DOS 4.x swappable data area list: Offset Size Description 00h WORD count of data areas 02h N BYTEs "count" copies of data area record Offset Size Description 00h DWORD address 04h WORD length and type bit 15 set if swap always, clear if swap in DOS bits 14-0: length in bytes Format of DOS 4.0-6.0 swappable data area: Offset Size Description -11 5 WORDs zero-terminated list of offsets which need to be patched to enabled critical-section calls (see INT 2A/AH=80h) (not actually part of the SDA; all offsets are 0D0Ch, but this list is still present for DOS 3.x compatibility) 00h BYTE critical error flag 01h BYTE InDOS flag (count of active INT 21 calls) 02h BYTE drive on which current critical error occurred or FFh 03h BYTE locus of last error 04h WORD extended error code of last error 06h BYTE suggested action for last error 07h BYTE class of last error 08h DWORD ES:DI pointer for last error 0Ch DWORD current DTA 10h WORD current PSP 12h WORD stores SP across an INT 23 14h WORD return code from last process termination (zerod after reading with AH=4Dh) 16h BYTE current drive 17h BYTE extended break flag 18h 2 BYTEs ??? ---remainder need only be swapped if in DOS--- 1Ah WORD value of AX on call to INT 21 1Ch WORD PSP segment for sharing/network 1Eh WORD network machine number for sharing/network (0000h = us) 20h WORD first usable memory block found when allocating memory 22h WORD best usable memory block found when allocating memory 24h WORD last usable memory block found when allocating memory 26h WORD memory size in paragraphs (used only during initialization) 28h WORD ??? 2Ah BYTE ??? 2Bh BYTE ??? 2Ch BYTE ??? 2Dh BYTE ??? 2Eh BYTE ??? 2Fh BYTE ??? (doesn't seem to be referenced) 30h BYTE day of month 31h BYTE month 32h WORD year - 1980 34h WORD number of days since 1-1-1980 36h BYTE day of week (0 = Sunday) 37h BYTE ??? 38h BYTE ??? 39h BYTE ??? 3Ah 30 BYTEs device driver request header (see INT 2F/AX=0802h) 58h DWORD pointer to device driver entry point (used in calling driver) 5Ch 22 BYTEs device driver request header 72h 30 BYTEs device driver request header 90h 6 BYTEs ??? 96h 6 BYTEs CLOCK$ transfer record (see AH=52h) 9Ch 2 BYTEs ??? 9Eh 128 BYTEs buffer for filename 11Eh 128 BYTEs buffer for filename 19Eh 21 BYTEs findfirst/findnext search data block (see AH=4Eh) 1B3h 32 BYTEs directory entry for found file (see AH=11h) 1D3h 88 BYTEs copy of current directory structure for drive being accessed 22Bh 11 BYTEs FCB-format filename for device name comparison 236h BYTE ??? 237h 11 BYTEs wildcard destination specification for rename (FCB format) 242h 2 BYTEs ??? 244h WORD ??? 246h 5 BYTEs ??? 24Bh BYTE extended FCB file attributes 24Ch BYTE type of FCB (00h regular, FFh extended) 24Dh BYTE directory search attributes 24Eh BYTE file open mode 24Fh BYTE ??? flag bits 250h BYTE ??? flag or counter 251h BYTE ??? flag 252h BYTE flag indicating how DOS function was invoked (00h = direct INT 20/INT 21, FFh = server call AX=5D00h) 253h BYTE ??? 254h BYTE ??? 255h BYTE ??? 256h BYTE ??? 257h BYTE ??? 258h BYTE ??? 259h BYTE ??? 25Ah BYTE canonicalized filename referred to existing file/dir if FFh 25Bh BYTE ??? 25Ch BYTE type of process termination (00h-03h) 25Dh BYTE ??? 25Eh BYTE ??? 25Fh BYTE ??? 260h DWORD pointer to Drive Parameter Block for critical error invocation 264h DWORD pointer to stack frame containing user registers on INT 21 268h WORD stores SP??? 26Ah DWORD pointer to DOS Drive Parameter Block for ??? 26Eh WORD segment of disk buffer 270h WORD ??? 272h WORD ??? 274h WORD ??? 276h WORD ??? 278h BYTE Media ID byte returned by AH=1Bh,1Ch 279h BYTE ??? (doesn't seem to be referenced) 27Ah DWORD pointer to ??? 27Eh DWORD pointer to current SFT 282h DWORD pointer to current directory structure for drive being accessed 286h DWORD pointer to caller's FCB 28Ah WORD SFT index to which file being opened will refer 28Ch WORD temporary storage for file handle 28Eh DWORD pointer to a JFT entry in process handle table (see AH=26h) 292h WORD offset in DOS DS of first filename argument 294h WORD offset in DOS DS of second filename argument 296h WORD ??? 298h WORD ??? 29Ah WORD ??? 29Ch WORD ??? 29Eh WORD ??? 2A0h WORD ??? 2A2h WORD ??? directory cluster number??? 2A4h DWORD ??? 2A8h DWORD ??? 2ACh WORD ??? 2AEh DWORD offset in file??? 2B2h WORD ??? 2B4h WORD bytes in partial sector 2B6h WORD number of sectors 2B8h WORD ??? 2BAh WORD ??? 2BCh WORD ??? 2BEh DWORD number of bytes appended to file 2C2h DWORD pointer to ??? disk buffer 2C6h DWORD pointer to ??? SFT 2CAh WORD used by INT 21 dispatcher to store caller's BX 2CCh WORD used by INT 21 dispatcher to store caller's DS 2CEh WORD temporary storage while saving/restoring caller's registers 2D0h DWORD pointer to prev call frame (offset 264h) if INT 21 reentered also switched to for duration of INT 24 2D4h WORD open mode/action for INT 21/AX=6C00h 2D6h BYTE ??? (set to 00h by INT 21h dispatcher, 02h when a read is performed, and 01h or 03h by INT 21/AX=6C00h) 2D7h WORD ??? apparently unused 2D9h DWORD stored ES:DI for AX=6C00h 2DDh WORD extended file open action code (see AX=6C00h) 2DFh WORD extended file open attributes (see AX=6C00h) 2E1h WORD extended file open file mode (see AX=6C00h) 2E3h DWORD pointer to filename to open (see AX=6C00h) 2E7h WORD ??? 2E9h WORD ??? 2EBh BYTE ??? 2ECh WORD stores DS during call to [List-of-Lists + 37h] 2EEh WORD ??? 2F0h BYTE ??? 2F1h WORD ??? bit flags 2F3h DWORD pointer to user-supplied filename 2F7h DWORD pointer to ??? 2FBh WORD stores SS during call to [List-of-Lists + 37h] 2FDh WORD stores SP during call to [List-of-Lists + 37h] 2FFh BYTE flag, nonzero if stack switched in calling [List-of-Lists+37h] 300h 21 BYTEs FindFirst search data for source file(s) of a rename operation (see AH=4Eh) 315h 32 BYTEs directory entry for file being renamed (see AH=11h) 335h 331 BYTEs critical error stack 480h 384 BYTEs disk stack (functions greater than 0Ch, INT 25,INT 26) 600h 384 BYTEs character I/O stack (functions 01h through 0Ch) 780h BYTE device driver lookahead flag (see AH=64h) 781h BYTE ??? looks like a drive number 782h BYTE ??? flag of some kind 783h BYTE ??? 784h WORD ??? 786h WORD ??? 788h WORD ??? 78Ah WORD ??? --------D-215E00----------------------------- INT 21 - DOS 3.1+ network - GET MACHINE NAME AX = 5E00h DS:DX -> 16-byte buffer for ASCIZ machine name Return: CF clear if successful CH = validity 00h name invalid nonzero valid CL = NetBIOS number for machine name DS:DX buffer filled with blank-paded name CF set on error AX = error code (01h) (see AH=59h) Note: supported by OS/2 v1.3+ compatibility box, PC-NFS SeeAlso: AX=5E01h --------D-215E01CH00------------------------- INT 21 - DOS 3.1+ network - SET MACHINE NAME AX = 5E01h CH = 00h undefine name (make it invalid) <> 0 define name CL = name number DS:DX -> 15-character blank-padded ASCIZ name SeeAlso: AX=5E00h --------D-215E02----------------------------- INT 21 - DOS 3.1+ network - SET NETWORK PRINTER SETUP STRING AX = 5E02h BX = redirection list index (see AX=5F02h) CX = length of setup string DS:SI -> setup string Return: CF clear if successful CF set on error AX = error code (01h) (see AH=59h) SeeAlso: AX=5E03h,INT 2F/AX=111Fh --------D-215E03----------------------------- INT 21 - DOS 3.1+ network - GET NETWORK PRINTER SETUP STRING AX = 5E03h BX = redirection list index (see AX=5F02h) ES:DI -> 64-byte buffer for setup string Return: CF clear if successful CX = length of setup string ES:DI buffer filled CF set on error AX = error code (01h) (see AH=59h) SeeAlso: AX=5E02h,INT 2F/AX=111Fh --------D-215E04----------------------------- INT 21 - DOS 3.1+ network - SET PRINTER MODE AX = 5E04h BX = redirection list index (see AX=5F02h) DX = mode bit 0: set if binary, clear if text (tabs expanded to blanks) Return: CF set on error AX = error code (see AH=59h) CF clear if successful Note: calls INT 2F/AX=111Fh with 5E04h on stack SeeAlso: AX=5E05h,INT 2F/AX=111Fh --------D-215E05----------------------------- INT 21 - DOS 3.1+ network - GET PRINTER MODE AX = 5E05h BX = redirection list index (see AX=5F02h) Return: CF set on error AX = error code (see AH=59h) CF clear if successful DX = printer mode (see AX=5E04h) Note: calls INT 2F/AX=111Fh with 5E05h on stack SeeAlso: AX=5E04h,INT 2F/AX=111Fh ---------------------------------------------