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DSZ.COM - ZMODEM-90(TM), True YMODEM(TM), XMODEM File Transfer Program Chuck Forsberg - Omen Technology Inc ─────────── DESCRIPTION: ─────────── DSZ is a "protocol driver" that uses the ZMODEM-90(TM), True YMODEM(TM), or XMODEM protocol to transfer files over a serial port with a variety of programs. ZMODEM Transfers feature 32 bit CRC, advanced file management, and Crash Recovery, ZMODEM Crash Recovery can be used to complete interrupted file transfers started with any protocol. DSZ has two main commands for ZMODEM transfers: "sz" sends file(s), and "rz" receives them. When calling bulletin boards to download files with ZMODEM you can avoid the bother of starting DSZ for each transfer by calling DSZ first, before asking the BBS for the download. dsz t The "t" command allows you to keyboard the file request directly to the BBS. (The "t" stands for "terminal emulation".) Just give the "dsz t" command from DOS or your comms program's DOS GATEWAY. DSZ's ZMODEM AutoDownload then receives the file automatically, using the filename provided by the BBS, without any wasted keystrokes or delay. Try it, you'll like it! (The "t" command is described below.) YMODEM downloads are almost as easy. Use the "t" command as shown above, and hit the F3 key after telling the board to download a file with YMODEM. ZMODEM and True YMODEM(TM) transfers preserve exact file length and modification time. DSZ supports XMODEM-1k (XMODEM with 1024 byte blocks, sometimes mislabeled as ymodem) and CRC-16 with the sx -k and rc commands. DSZ is derived from Omen Technology's "Professional-YAM" high reliability communications tools (also known as PowerCom(TM)) and Omen Technology's ZCOMM User Supported Communications Software. DSZ supports a subset of Pro-YAM's file transfer related commands. This documentation makes extensive references to contemporary editions of the Pro-YAM or ZCOMM manual, and is incomplete without it. (Registered copies include an alternate, copyrighted file.) DSZ is usually called from a communications or bulletin board program. DSZ uses its own modem I/O. The original interrupt vector, UART parity, and interrupt configuration are restored on exit. The original state of the 8259 interrupt mask bit for this vector is also restored on exit. 1 DSZ uses DOS standard output (stdout) for messages. DSZ never writes directly to the screen. DSZ expects its standard output to point to the console, a logging file, or NUL, but never the modem port. If dsz's standard output is redirected to the modem (as with ProComm's Host mode DOS shell), the combination will lock up the computer. When necessary, dsz's standard output can be redirected back to the console device with the CON command. Users of pcAnywhere must use dsz's A command to disable pcAnywhere host mode during file transfers. DSZ exits with 0 status for successful transfers, or the value of the Q parameter (default 1) if a file transfer failed, or if no files were transferred. Many languages and "door" programs do not return this information to the calling program. Some languages and "door" programs freak out (hang) on certain non-zero exit values. A batch file that calls DSZ directly may be used to detect the DSZ exit status with the DOS "errorlevel" construct. Please refer to the Q numeric parameter below for more information. DSZ's log file entries may also be examined to determine the success or failure of a file transfer. ──────────────────────── DSZ.COM SETUP PARAMETERS: ──────────────────────── Except as noted, all commands and options must be typed in lower case. DO NOT USE UPPER CASE!! Optional commands or arguments are shown in square brackets []. When used (in any combination), the A, CON, port, speed, handshake, estimate, and d commands must be used in exactly this order: DSZ.COM [A] [CON] [port N] [speed S] [handshake] [D] [d] [pxN] file transfer command [A] Suspend pcAnywhere operation during file transfers. The A command is used to avoid lockups caused by pcAnywhere host mode. This command should be given to the program running under pcAnywhere host mode. EXAMPLE: C>dsz A sz *.foo Sends files from a pcAnywhere hosted machine to you. Fm: Al de la Torre 1. sending from host to remote 2 type: "dsz A sz filename.ext" ENTER shell to dos on remote machine (ctrl-Rshift) type: "dsz A rz" ENTER 2. sending from remote to host type: "dsz A rz" ENTER shell to dos on remote machine (ctrl-Rshift) type: "dsz A sz filename.ext" ENTER [CON] Redirect message output to the DOS "CON" (console) device, overriding any previous redirections. This is necessary to avoid lockups caused by ProComm host mode. Most programs do not require this hack. This command is unique to DSZ. [port N] select port N (n = 1,2,3,4,5,6,7,8, 10,11,12,13,14,15,16,17,18) Default is port 1 (COM1) or read from the DSZPORT dos environment variable. COM11 to COM18 refer to the COM1 to COM8 ports on the PS/2. DSZ's COM3 uses 3E8 and IRQ4. DSZ's COM4 uses 2E8 and IRQ3. DSZ's COM7 uses 3E8 and IRQ5. DSZ's COM8 uses 2E8 and IRQ5. If you wish to use COM3 or COM4 and your computer is not wired according to one of these choices, you MUST use the "portx" command to specify base address and interrupt vector. EXAMPLE: to use COM2: dsz port 2 rz In multitasking operation, accessing a port used by another running program will hang the machine. [portx base,irq] To select an arbitrary port address and interrupt vector, the portx command must be used instead of the port command. EXAMPLE: dsz portx 3e8,4 speed 2400 rz [speed S] Set the specified speed. This command is rarely needed because DSZ reads the port's current speed by default. DSZ supports a maximum speed of 38400. Please study all the chapters of this document when using speeds above 2400 bps. 3 [handshake (ON) (BOTH) (SLOW)] Enable one of several choices of handshake (ie Flow Control). ON enables CTS/RTS Hardware Flow Control; BOTH enables CTS/RTS Hardware Flow Control *And* XOFF/XON software Flow Control; SLOW has been added to disable the RTS signal to the modem while writing to disk, even if the interrupt buffer is not chock full of bytes. This should help systems with excessive interrupt latency on disk writes. (see Got Zpros section towards end of manual) In DSZ the "handshake" command may be abbreviated to "ha". [estimate (length) (speed)] Use the specified length and optional specified effective transfer speed for the next receive file to be created. This command must come *after* any port, speed, or handshake commands. The following makes DSZ calculate file transfer times on the basis of 290 character per second aggregate transfer rate: EXAMPLE: dsz port 2 speed 9600 estimate 0 2900 rz EXAMPLE: dsz port 2 speed 9600 estimate 0 2900 sz bimama.zip [D] Disables the modem (drops Data Terminal Ready, DTR) if carrier is lost. This may be used to prevent spurious events (phone ringing) from interfering with the calling bulletin board's recovery from carrier loss. [d] Disables carrier dropout monitoring, for modems that do not properly drive the "Carrier Detect" input on the PC. If you see a No Carrier Detect message, you need to give the d command. Before using the d command, make sure you have the proper port selected!!! [LARG] Convert ARG to lower case, then parse arg. [pxN] Set a numeric parameter x to N. These parameters are mostly a subset of the Pro-YAM/ZCOMM numeric parameters, and are listed below. They assume their defaults each time DSZ is called. Without an argument, p displays the numeric parameters and their values. EXAMPLE: C>dsz p z pxN Set zmodem numeric parameter x to N. These parameters correspond to the Pro-YAM or ZCOMM "zmodem" parameters and rarely need changing. 4 These parameters assume their defaults each time DSZ is called. Without an argument, z p displays the zmodem numeric parameters and their values. [restrict] Restrict pathnames to the current disk and directory tree, and disallow overwriting of existing files. When DSZ is restricted, it will refuse to transfer files containing the string autoexec.bat and command.com in upper or lower case. This provides some defense from malicious uploaded files. [t] (-T) (-8g) Talk with ZMODEM AutoDownload. DSZ's ZMODEM AutoDownload(Tm) detects the start of a ZMODEM file download and accepts the file(s) without operator intervention. The optional -T forces DSZ to exit after it has recognized a ZMODEM AutoDownload(Tm) request. The optional -8g (available on registered copies only) enables reception of "BBS (ANSI) graphics" displays. (A video device driver such as ANSI.SYS must be loaded to support some types of graphics.) A small subset of ZCOMM/Pro-YAM term function subcommands are recognized. Keyboard F1 or ALT-X to exit. F3 receives file(s) with True YMODEM(TM), ALT-P toggles parity between the 8n default and 8g (enables ANSI "graphics"). ALT-H toggles two local echo ("Half Duplex") modes; the second displays a newline (CR/LF) when Enter is keyboarded. Keyboarded ASCII characters are sent to the modem. ALT-B sends a break. Characters from the modem print on the screen. A device driver such as ANSI.SYS may be used to recognize escape sequences. [o] Turn off Data Terminal Ready (DTR), terminating ("offing") the connection if the modem responds to DTR. Useful with the "t" command to disconnect afterwards. EXAMPLE: dsz t o ──────────────────────────────────────── NUMERIC PARAMETERS: THE pxN COMMAND ──────────────────────────────────────── DSZ uses the following main numeric parameters, settable with the pxN command. EXAMPLE: dsz pQ0 B Set the size of buffer used for disk reads and writes. The default is 1024, 4096 maximum. (16384 max on DSZ.EXE) If your copy of DSZ is running 5 on a floppy disk system or a very slow turkey hard disk, a larger value may give better results. Too large a value may exhaust memory, induce receiver timeouts, cause disconnects(!), or generate spurious CRC errors. If performance logging doesn't work, this parameter is too big. EXAMPLE: C>dsz pB4096 sz A:floppy.fil Setting the buffer size may lock out the performance log, DSZFILES, and/or indirect pathname list in the "tiny model" DSZ flavor. IF YOU AREN'T BLOODY SURE YOU NEED A BIGGER BUFFER, DON'T USE ONE. O This parameter controls XMODEM OverThruster(TM). CompuServe XMODEM Negative numbers control the number of bytes added to the window on XMODEM downloads from the CompuServe Information Service. Larger numbers increase throughput, but cause improperly interfaced MNP modems on CIS nodes to drop characters under stress, disrupting the file transfer. EXAMPLE: dsz pO-512 ro file1.ext Other XMODEM Positive numbers up to a system dependent value less than the protocol block size increase throughput. Larger values induce timeouts and/or retransmitted blocks. The optimum value must be determined by experiment. 60 usually give best results with MNP modems at 2400 bps. The optimum value varies depending on the remote computer, modem(s), system traffic, and the network node. EXAMPLE: dsz pO60 ro file1.ext P After a "speed" command, giving a p command (display parameters), the P parameter value will indicate the type of serial I/O UART chip detected. DSZ automatically detects and enables the FIFO buffer on the NS16550A and Intel 82510 chips. EXAMPLE: dsz port 1 speed 19200 p 0 Indicates a standard 8250 or 16450 UART with no special features. 1 Indicates an NS16550A with 16 deep receive buffering. This is the preferred chip. 2 Indicates an Intel 82510 with 3 deep receive buffering. The sequence "port 1 pP1 speed 19200" bypasses DSZ's verification checks normally performed on the FIFO configuration and may allow a defective FIFO on certain chips to be used. This incantation is not required for the NS16550A. Q Error code returned to DOS (default 1). (Success always returns 0.) Some programs toss cookies when confronted with certain exit codes. 6 EXAMPLE: C>dsz pQ-1 sz foo.bar DSZ reports an error if no files have been transferred, even if the command used wasn't supposed to transfer any file(s). S Timeout in seconds (default 15) waiting for restraint release (XON and/or handshake). W Wait for Enter key before exiting after an error. Effective only on registered copies. Useful when calling DSZ from DESQview, allows the window to close unless there is an error message that should remain visible. EXAMPLE: C>dsz pW1 sz foo.bar a Calibrates certain protocol timeouts used with XMODEM and YMODEM transfers (Cybernetic Data Recovery(TM)). This parameter does not affect ZMODEM transfers. The a numeric parameter is automatically set to 2000 for a 4.77 mHz PC or XT, 4000 for a PS2/30, 6000 for an 8 mHz 1ws AT, and 12000 for a PS2/80. If your computer has a speedup card or otherwise runs unusually fast (or slow!) for its type, you may set the a numeric parameter to a value that reflects its speed. EXAMPLE: dsz port 2 pa4000 rb NOTE: Setting this parameter does not suppress the "Unknown Machine Type" message which is displayed before the command line is scanned. d A non zero value (the default) causes incoming files received with ZMODEM and full YMODEM transfers to have their Date set to that sent in the file header. ZMODEM's file management features depend on the transmission of each file's modification date. Files will have the same creation date, even if the two machines are in different time zones. When transferring files to/from a Unix system, creation dates are interpreted according to GMT or Universal Coordinated Time. File dating may be disabled with a pd0 command. NOTE: Backdating file creation times may confuse some backup programs. v Verbose level (debugging output) Negative values inhibit some routine messages. Setting v to 1 or greater causes serialized copies to ring the bell when a transfer is done. z Timezone in minutes behind GMT, used for ZMODEM and True YMODEM file transfers to coordinate the actual date of the file with computers in other time zones. Effective on registered copies. PDT or MST corresponds to 420. This may be preset with the ZONE DOS environment variable. 7 ────────────────────── FILE TRANSFER COMMANDS: ────────────────────── DESCRIPTIONS OF PROTOCOLS SUPPORTED BY DSZ.COM XMODEM The Ward Christensen file transfer protocol uses 128 byte packets, one byte control messages, and a one byte arithmetic checksum. XMODEM/CRC A synonym for the enhanced Ward Christensen XMODEM protocol using a Cyclic Redundancy Check (CRC-16). Newer programs support CRC-16 for better data integrity, but reliability is still compromized by one byte control messages. XMODEM-1k XMODEM protocol with 1024 byte data packets, CRC-16, and one byte control messages, sometimes incorrectly called ymodem. YMODEM is a batch file transfer protocol with pathname, date, file length and other file data in block 0, CRC-16 default, and optional 1024 byte packets. Many programs claiming to support YMODEM actually use XMODEM with 1024 byte blocks; use ZCOMM's sx -k and rx XMODEM commands with these mutants. ZMODEM An advanced public domain file transfer protocol with simplified human interface, crash recovery, high speed streaming, sensitive 32 bit CRC, command download, security features, and important file management functions. file transfers with traditional protocols. ZMODEM + ZMODEM data transfers are protected by the Federal Standard 32 bit CRC to assure reliable transfers. This 32 bit CRC gives an undetected error rate five orders of magnitude better than XMODEM's 16 bit CRC, and more than a billion times better than checksum XMODEM. ZMODEM uses 16 bit CRC for file transfers with programs that do not support 32 bit CRC. + Most important, all ZMODEM protocol transactions are protected by CRC. Some competing protocols advertising 16 or 32 bit CRC fail under stress because transactions use single characters not protected by CRC. ZMODEM supports Crash Recovery and advanced file management. If you've ever been disconnected when a huge file transfer was almost finished, you'll appreciate resuming/recovering the file transfer with the ZMODEM r option. You can use the n option to transfer only those files that have changed since the last time they were transferred. 8 With the p option, you can unconditionally protect files that already exist on the destination system. To update only the files you already have while skipping the rest, use the Yn option. To send a file with ZMODEM, the command sz file1 can be given from either the main command prompt, or from a secondary command prompt obtained with ALT-2. Multiple files and wild cards may be used. EXAMPLE: sz file1 file2 *.lst If Z mode has been enabled (the default), ZCOMM's term function will detect a ZMODEM transmission and receive the file(s) automatically, after a security check. Otherwise, the rz command may be given from a command prompt. Please refer to the sz and zcommand commands for examples. ──────> NEW-NEW-NEW!!! with the 1-22-90 edition of DSZ you get: MobyTurbo(Tm) MobyTurbo optimizes throughput on ZIP, ARC, and similar files over paths that support YMODEM-g (or would except for random errors). MobyTurbo cannot be used with most types of software flow control (or "handshake both"). Activate MobyTurbo with the -m option to one or more of: sz, rz LOCK OUT MobyTurbo with the -M option. -M is effective until the next "call" command. TRUE YMODEM Developed in 1981, YMODEM extensions to XMODEM are finding their way into many communications programs. Rb and sb programs are available for Unix and VAX/VMS. With Omen's Enhanced Data Recovery(TM), YMODEM gives excellent efficiency, integrity, and good robustness. True YMODEM transfers one or more files in a batch without alteration or added garbage characters. True YMODEM preserves the file date across multiple time zones. ZCOMM and the Unix(TM) rb and sb programs and ZCOMM preserve the file modification date.[2] The sb k option (1024 byte blocks) may be used to enhance throughput, especially when using timesharing systems, satellite links, or packet networks that can support the longer blocks. EXAMPLE: sb -k *.c *.h sends all .c and .h files in the current directory with 1024 byte blocks.[3] YMODEM Batch files can be received with the rb or F3 commands. 9 YMODEM Batch file transfers with Unix and VMS systems are discussed later in this chapter. Many programs claiming to support YMODEM actually use XMODEM with 1024 byte blocks; use ZCOMM's sx -k and rx XMODEM commands with these imposters. XMODEM-1k The XMODEM-1k protocol transfers one file per command with 1024 byte blocks and a nominal 16 bit CRC. The file name must be entered for both the sender and the receiver. Programs lacking ZCOMM's Cybernetic Data Recovery(TM) logic are less likely to transfer data accurately under marginal conditions. XMODEM's use of every possible 8 bit code limit its effectiveness in many applications. The end of the file may be padded by up to 127 or 1023[4] garbage characters. To send a file: sx -k file1 2. Controlled by the d and z numeric parameters 3. ZCOMM switches to 128 byte blocks at the end of a file when the length warrants. 4. Some programs (including ZCOMM) limit this padding to 127 bytes. To receive a file: rc file1 XMODEM/CRC The XMODEM/CRC protocol transfers one file per command. The file name must be entered for both the sender and the receiver. Programs lacking ZCOMM's Cybernetic Data Recovery(TM) logic are less likely to transfer data under marginal conditions. XMODEM-CRC's short data blocks and use of every possible 8 bit code limit its effectiveness in many applications. The end of the file may be padded by up to 127 garbage characters. To send a file: sx file1 To receive a file: rc file1 10 XMODEM The original MODEM protocol, developed by Ward Christensen, is supported by a large and growing number of programs operating on a variety of micros and minis. The base level XMODEM protocol gives good results when used over low error rate direct telephone connections. XMODEM's short data blocks and use of every possible 8 bit code limit its effectiveness in many applications. File transfers with this protocol add up to 127 garbage characters to transferred files. The XMODEM protocol can transfer one file per command. The file name must be entered at both the sender and the receiver. To send a file with plain XMODEM: sx file1 To receive a file with XMODEM: rx file1 XMODEM with OverThruster XMODEM file downloading from networks and timesharing systems is slowed by short blocks and long response times. With some systems, one can speed up downloads by using the ro command to receive the file. Because OverThruster defeats error recovery, a line hit will usually abort a download. With nearly error free connections, one can save enough time from the increased throughput to make up for failed transfers. OverThruster may be used with X.PC or MNP error correcting link level protocols. EXAMPLE: ro file1 Clink/SEAlink Batch When transferring files with the SEA CLINK 1.13 or compatible programs, DSZ's rb and sb commands recognize SEAlink's modified Telink protocol. The rb command allows a transmitting SEAlink program to use sliding windows. Telink time zone and file name considerations apply to SEAlink. In addition, because SEAlink uses all 256 of the possible 8 bit codes for both data transfer and protocol management, some modems and networks that operate with XMODEM will not accomodate SEAlink. As with the MODEM7 and Clink protocols mentioned above, the SEAlink protocol is included for convenience in situations where the YMODEM and ZMODEM protocols are not implemented. EXAMPLE: zmodem pZ120; sb file1.ext *.baz Sends the specified files to a SEAlink program with a 2 hour time zone adjustment. EXAMPLE: rb -z60 Receives one or more files from a SEAlink program with a 60 minute time zone adjustment. 11 ──────────────────────────────────────────────── ADDITIONAL DESCRIPTIONS OF FILE TRANSFER COMMANDS: ──────────────────────────────────────────────── rb [-options] Receives with options 1 or more files using YMODEM batch protocol. The rb command also receives files sent with Clink/SEAlink protocol. The pathname and length of each file are transmitted in batch mode. If a file is received in error (retries exhausted, etc.), the batch transfer will terminate. If privileges are restricted, a file received in error will be unlinked (erased). EXAMPLE: rb -y Many programs claiming to support YMODEM actually use XMODEM with 1024 byte blocks; use ZCOMM's sx -k and rx XMODEM commands with these imposters. SEE ALSO: YMODEM Batch protocol, Chapter 11. rb [-options] [dir] [file ...] Receives with options 1 or more files using YMODEM batch protocol. An optional disk and/or directory dir may be specified. The optional supplied pathnames file ... are used in place of pathnames normally provided by the sending program. If the sending program attempts to send more files than the number of names supplied to the rb command, the transfer is aborted. rc [-options] file Receives with options a single file using the Christensen XMODEM protocol, 128 or 1024 byte blocks, and CRC-16 instead of an 8 bit checksum. ZCOMM signals the sending program that CRC-16 is to be used. After four errors while attempting to receive the first sector, ZCOMM will cancel the CRC-16 option and reverts to checksum operation. The probability of an undetected transmission error is much less if CRC-16 is used in place of the default 8 bit arithmetic checksum. Omen Technology Inc Recommends use of the 16 bit CRC to maintain data integrity at professional levels. CRC-16 is not the default because most IBM bulletin boards and commercial modem programs only support the 8 bit checksum. Chapter 17 describes the available options to the rc command. If privileges are restricted, a file received in error will be deleted. ro [-options] file Receives with options a single file using non- standard XMODEM-CRC protocol logic. OverThruster(TM) speeds file downloads at the expense of error recovery. OverThruster operation is controlled by the O numeric parameter (q.v.). As fans of Buckaroo Bonzai know, the OverThruster is not universally applicable. A transmission error will almost always terminate an OverThruster file download. 12 If Restricted, a file received in error will be unlinked (erased). EXAMPLE: ro foo.com SEE ALSO: O numeric parameter rx [-options] file Receives with options a single file using the Christensen XMODEM protocol. Chapter 17 describes the available options. If restricted, a file received in error will be unlinked (erased). EXAMPLE: rx foo.com rz [-options] Receives with options 1 or more files using ZMODEM protocol. Each file's pathname is obtained from the sending program. The +, a, b, n, N, r, and y options are accepted from the sending program, subject to restriced privileges. If the +, b, n, N, r, or y option is specified to the receiver, it overrides any contrary options specified to the sender. Only one of the a, b, or r options may be specified. Only one of the +, n, N, or y options may be specified. If a file is received in error (retries exhausted, etc.), the batch transfer will terminate. If privileges are restricted, a file received in error will be unlinked (erased). EXAMPLE: rz -y rz [-options] [dir] [file ...] Receives with options 1 or more files using YMODEM batch protocol. An optional disk and/or directory dir may be specified. The optional supplied pathnames file ... are used in place of pathnames normally provided by the sending program. If the sending program attempts to send more files than the number of names supplied to the rz command, the transfer is aborted. To allow use of the rz command, Z mode (ZMODEM autodownload) should be turned off with a dis -Z command. sb [-options] pathspec Send the files specified in pathspec using the YMODEM Batch Protocol. The pathname, length, and modification time of each file are transmitted. Files which cannot be opened are skipped. An empty pathspec sends all files in the current directory. A directory name expands to all regular files in that directory. If an error aborts a file transmission (retries exhausted, etc.), batch transfers terminate. The sb command will send files with Clink/SEAlink protocol if the receiving program requests Clink. EXAMPLE: sb -k *.com sends *.com using 1024 byte packets. 13 NOTE The receiver must be commanded to receive the files with an rb or rz command. sx [-options] file Send a single file using the Ward Christensen XMODEM or XMODEM/CRC protocol. The receiving program may request use of a 16 bit CRC, which is more accurate than the default checksum. DOS files sent this way will have Control-Z (CPMEOF) garbage characters appended to make the file length a multiple of the packet size. EXAMPLE: sx foo.com EXAMPLE: sx -k foo.com (1024 byte blocks) NOTE: The receiver must be commanded to receive the file with an rx filename or rc filename command. sz [-options] [PREFIX=p | ONAME=x] pathspec Send the files specified in pathspec using ZMODEM Batch Protocol. The +, a, b, n, N, r, and y options are sent to the receiving program. Only one of the a, b, or r options may be specified. Only one of the +, n, N, or y options may be specified. The pathname, length, and modification time of each file are transmitted. Files which cannot be opened are skipped. An empty pathspec sends all files in the current directory. A directory name expands to all regular files in that directory. If ONAME=x is given after the options (if any) and before the file name(s), x will be used as the COMPLETE destination pathname instead of each file's actual pathname. Examples: EXAMPLE: sz -y ONAME=B:/spiked/secret /soviet/sdi/newlaser.doc results in the destination file secret on drive B: in the /spiked directory. (Destination directories must exist and be writable). If instead PREFIX=p is given after the options (if any) and before the file name(s), p will bew added to the destination pathname(s) as a prefix. EXAMPLE: sz -y PREFIX=C:/FOO.BAZ/ /biff/bam/aardvark.wak results in the destination file "C:/FOO.BAZ/aardvark.wak" (the destination directories must exist and be writable). EXAMPLE: sz *.com Sends all files with a .com extension. EXAMPLE: sz -r ??log Crash Recovery sends only the new data if the receiver has incomplete versions of these files. EXAMPLE: sz -fn src/*.c src/*.h maildir 14 sends only the newer source files in the src subdirectory, and all new files in the maildir subdirectory. EXAMPLE: zcommand "sz -fn /bin /wp" commands a remote ZCOMM system in Host Operation (unrestricted) to send all new files in the /bin and /wp directories. EXAMPLE: sz -Yn *.c sends only newer versions of files that already exist at the destination. szb [-options] [PREFIX=p | ONAME=x] pathspec As above, but "falls back" to YMODEM if the receiver cannot receive with ZMODEM protocol. ────────────────────────────────── EXAMPLES OF FILE TRANSFER COMMANDS: ────────────────────────────────── RECEIVE (DOWNLOAD) COMMANDS: --------------------------- ┌─ Transfer Command ┌──── Transfer Options │ │ rz [-abeEmMnpPrt+YZy] [dir] [file ...] (ZMODEM-90 receive) rz [-abenprt+Yy] [dir] [file ...] (ZMODEM receive) rb [-abt+y] [dir] [file ...] (YMODEM receive) rb -g [-abt+y] [dir] [file ...] (YMODEM-g receive) rc [-abt+y] file1 (XMODEM/CRC receive) ro [-abt+y] file1 (XMODEM OverThruster receive) rx [-abt+y] file1 (XMODEM receive) rx -g [-abt+y] file1 (Qmodem-G receive) **** Download directory specification and -g ignored w/o registration**** TRANSMIT (UPLOAD) COMMANDS: -------------------------- sz [-abefnprtFYQS+yZ] [-w[N]] [PREFIX=p | ONAME=n] file (ZMODEM send) sz [-abeEfmMnpPrtFYQS+yZ] [-w[N]] [PREFIX=p | ONAME=n] file (ZMODEM-90) Pathnames are separated by spaces. Wildcards are OK. 15 sb [-ft] [PREFIX=p | ONAME=n] file (YMODEM or YMODEM-g send) sb -k [-ft] [PREFIX=p | ONAME=n] file (YMODEM-1k or YMODEM-g send) sx [-t] file1 (XMODEM, XMODEM/CRC,Qmodem-G send) sx -k [-t] file1 (XMODEM-1k send) Send files may be specified indirectly: dsz sz @C:files.lst sends the files in C:files.lst. This provides another means of bypassing the DOS command line limit. The first letter must be "@" and the third letter must be ":" to distinguish this from an ordinary pathname. Pathnames in the indirection file may be separated by any combination of space(s), tab(s), CR and/or LF. No spaces may appear inside a pathname; "FOO .BAR" won't work. ───────────────────── FILE TRANSFER OPTIONS: ───────────────────── Options modify the way the protocol file transfer commands send and receive files. They are reset before each command line. The a and b options are mutually exclusive. With ZMODEM, a b option given to the sender or receiver will override any a option. The +, r, N, n, p, and y options are mutually exclusive. The Y option may be followed by the +, r, n, or N option. Specifiying these options to the receiver overrides the ZMODEM sender's specification of these options. + When receiving to a file already on disk, append the new data to the old file (if one exists). This option is not allowed if DSZ.COM is Restricted. When sending files with ZMODEM, the + option commands the receiver to append to a file already on the receiver's disk. EXAMPLE: sz -+ ONAME=master.log *.log sends all .log files in the current directory to be appended to master.log on the receiver's computer. a (ASCII) The a option applies to files received with XMODEM, YMODEM, 16 or ZMODEM protocol. It converts newlines not preceded by CR to CR/LF pairs. NULL, RUBOUT, and all characters in each packet beginning with Ctrl-Z are excluded. The a option is useful when receiving text files without carriage returns directly from Unix systems. When sending with ZMODEM, the a option instructs the receiver to convert text files to the conventions used in its operating environment. The a option does not apply to Kermit. Files transferred with the a option cannot be processed with the ZMODEM r (recover/resume) option. EXAMPLE: rc -a program.c receives program.c and converts end of lines to CR/LF. b (Binary) With ZMODEM, inhibits the receiver from translating the file contents. If either the ZMODEM sender or receiver specifies b option, any contrary requests will be ignored. EXAMPLE: sz -b program.exe e Normally, ZMODEM senders escape XON, XOFF, Ctrl-P, CR-@-CR, and Ctrl-X, and ZMODEM receivers ignore XON and XOFF. The e option escape all control characters when sending files with the ZMODEM protocol. SEE ALSO: zmtxesc, zmrxesc string parameters E With ZMODEM-90, force 8th bit encoding even if the transmission medium appears to support 8 bits.[2] f Send the full pathname as specified (exclusive of disk identifier) when using a batch send command. Normally only the file name portion (without any directory prefix) is transmitted. The f option applies to batch file transmission with the kermit sb, sb, send, and sz commands. EXAMPLE: cd /src; sz -f robot/r2d2.h sends the file with the pathname robot/r2d2.h. EXAMPLE: sz -f /src/robot/vox/3tpi0.* SEE ALSO: PREFIX=p flag for the sb and sz commands. F Insert a pause after each transmitted data subpacket transmitted with ZMODEM. This is useful in certain situations when conventional flow control methods are unavailable, ineffective, or 17 unreasonably slow (i.e., "broken"). The length of pause is set by the zmodem F numeric parameter. EXAMPLE: sz -F honker.dat SEE ALSO: zmodem F numeric parameter g Given to the receiving program, the g option to the rb command allows the sender and receiver to dispense with acknowledging each transmitted packet when using YMODEM batch transfers. YMODEM-g increases throughput when the transmitting medium itself (direct connection, X.PC session, or error correcting modems) provides error free transmission. The transmitting medium can use XOFF and XON to enforce flow control. If the transmitting medium does not enforce flow control,[3] the user must insure the receiver is not overrun. ZCOMM on a PC or XT accepts data at 9600 bps without flow control when the file is being written to a hard disk or ramdisk, provided no memory resident programs or special drivers hog CPU cycles. If an error is detected when the g option is used, the transfer is aborted. EXAMPLE: rb -g The g option may also be used with the rx command to receive files from Qmodem's G protocol. k Use 1024 byte (1K) packets with the sb and sx commands. The default packet length is 128. This increases throughput when the speed is high relative to the response times of the communications channel and the computers. The k option is useful with 9600 or 19200 bps transfers with directly connected timesharing systems. The k option may not work properly uploading to some systems, particularly heavily loaded or poorly implemented timesharing systems at high speeds. The k option is valid only when sending to ZCOMM, Unix rb, or other compatible programs. If the file length is not a multiple of 1024, the remainder of the file will be sent with 128 byte blocks. This option does not affect Kermit transfers. EXAMPLE: sb -k *.c *.h With the sz command, the k option forces an initial 1024 byte subpacket length. m (ZMODEM-90) Activate Moby Turbo(TM) for maximum throughput on compressed files sent over completely transparent connections. Moby Turbo can not be used with software flow control or over networks that reserve control characters. 18 M Lock out Moby Turbo even if the other program has given the m option. This is useful if the transmission path does not support complete transparency. n (ZMODEM) Each file is transferred if the corresponding destination file does not exist, or if the source file is newer. The n option can be given with either the sz or rz commands. This option is not allowed if the receiver is Restricted. EXAMPLE: sz -n *.* attempts to send all files in the current directory. Only those files that do not exist in the destination directory, and those for which the source is newer will be sent. N (ZMODEM) Transfer the file if the corresponding destination file does not exist, or if the source file is newer or longer. The N option be used with the sz and rz commands. This option is not allowed if the receiver is Restricted. EXAMPLE: sz -N *.* p (ZMODEM) Protect destination file; bypass this file if it already exists on the destination system. P (ZMODEM-90) When transferring files over 7 bit paths, pack 4 8-bit bytes into 5 7-bit bytes for transmission instead of quoting the 8th bit. This increases transmission speed on compressed files. q (Quiet) suppresses block by block status line update during Kermit and X/YMODEM file transfers. r (ZMODEM) Resume/Recover an interrupted file transfer with the ZMODEM protocol. May be given with either the sz or rz commands. The r option may be used to resume the transmission of a long file after a disconnect or power loss, without having to start over at the beginning of the file. The r option may also be used when the source file grows from time to time and only the incremental portion needs to be sent. The r option assumes that the contents of the destination file are identical to the corresponding beginning portion of the source file. The r option should not be applied to a file that has been modified by the a option, or to a file that has been edited on the destination system. This option is not allowed if the receiver is Restricted. EXAMPLE: sz -r hugefile.lst 19 rrr As above, but the files are compared by taking a 32 bit CRC on the contents before deciding on whether to start a fresh transfer. EXAMPLE: sz -rr maybenewer.lst With the -rr option, all of the files are compared or transmitted by default. The number of bytes used in the comparision may be restricted by setting the zmodem R numeric parameter to a number between 2048 and 32000 (1 billion on 32 bit flavors). EXAMPLE: zmodem pR20000 s SlugBait modifies the logic of ZMODEM sending to detect and report attempts at evading accountability for receiving files. Such attempts are flagged with a Q status in the log of sent files. SnailBait adds a slight delay to file transmission, and a transfer that is cut off at the very end of file may very infrequently be reported with Questionable instead of ERROR status. S When sending file(s) with ZMODEM, interrogate the receiving prgram for its serial number. S option terminates when a serial number is received or when the call command is given. Receiving file(s) with YMODEM or ZMODEM from programs providing a serial number also provides the other program's serial number. The serial number received is listed by the performance log. t Enter the term function after file transfer(s) complete. The t option should not be used in commands given from within the term function, either directly or with soft key definitions. u Unlink (remove, delete) the file after it has been sent with the sz command. v View the data being transmitted or received. Only correct data is displayed. Viewing standard ASCII files does not interfere with correct transmission at high speeds, although throughput may be degraded. The output may be redirected to a capture file or DOS device with the > or >> command. Unless output is redirected, this option must not be used when ZCOMM is in Host Operation. NwN Use a window size of N bytes with the sz command, overriding the zmodem w numeric parameter. If N is missing, use a ZMODEM window size of 4096 bytes. 20 SEE ALSO: Flow Control Chapter 13, zmodem w numeric parameter NWN Request the sending program to use a window size of N bytes, overriding the sender's window size setting, 4096 bytes if N is missing. y Yes it is OK to replace a file already on disk when receiving a file. If absent, the operator is given a choice of appending to the current file (a), erasing it (y) or aborting (n). This option is not allowed if ZCOMM is Restricted. When sending with ZMODEM, commands the receiver to replace a file on its disk. Y (ZMODEM) Transfer only those files for which a file with the same pathname exists at the destination, overwriting the destination files. The Y option may be followed by other ZMODEM options to further qualify the selection of files to transfer. This option is not allowed if ZCOMM is Restricted. EXAMPLE: sz -Yn *.* If the source directory contains files A, B, and C, each dated today, and the destination directory contains B TzT Use T minutes behind GMT (Greenwich Mean Time) as the local timezone instead of the z parameter value for the file(s) transferred with this command. EXAMPLE: sb -k -z300 ESTfile sends ESTfile corrected for creation in Eastern Standard Time. Z Transmit files with compression. The ZMODEM receiver must indicate its ability to decompress received files for this option to take effect. When sending between Unix systems, files are compressed with 12 bit Lempel-Ziv compression. Otherwise, packets are transmitted with Run Length Encoding. Over slow channels, compression increases the transmission speed of compiler listings, screen dumps, etc. by up to 50 per cent. LZW compression is more effective on more types of data than RLE compression. Some files, including the Personal Computing Magazine ASCII Test File, speed up by more than an order of magnitude with either RLE or LZW compression. Heavily encrypted data and compressed files, including ARC and ZOO archives, do not benefit from ZMODEM compression. The situation with fast compressed modems is more complex. The benefits of ZMODEM compression will depend on the particular application; try the transfers with and without ZMODEM compression to determine the most efficient options. 21 ───────────────────────────────────────────────────── EXAMPLES OF FILE TRANSFER COMMANDS & SETUP PARAMETERS: ───────────────────────────────────────────────────── dsz sz c:foo.arc (send 1 file with ZMODEM) dsz sz -m c:*.zip (send all .ZIP files with MobyTurbo) dsz sz f1.c f2.c f3.c (send 3 files with ZMODEM) dsz sz c:foo.* b:*.c (send multiple files with ZMODEM) dsz sz -Z *.lst (send text files with compression) dsz sz -r bigone.arc (CRASH RECOVERY: resume interrupted transfer) dsz rz -r (CRASH RECOVERY: resume interrupted transfer) dsz rz -rr (CRASH RECOVERY with file comparison) dsz handshake both sz yzmodem.arc (Hardware+Software handshake) dsz sz -n *.* (send files that are newer or rx has no copy) dsz sz -Yn *.* (Only send files that are newer than receiver's copy) (Do not send files that do not exist on receiver's disk) dsz rz C:/UPLOADS (receive files to specified directory #) dsz port 2 speed 38400 handshake both restrict rz (Restrict provides protection for BBS's) dsz rz -y prog.arc (ZMODEM, single file pathname override) dsz z pr1 rx foo.dat (XMODEM receive, remove file if error) dsz pO60 ro foo.dat (XMODEM/OverThruster receive, GEnie MNP #) DSZ LRC L-Y NEWPROG.ARC (generate lower case "rc -y" command) dsz sz foo >debug.dmp (Debugging data dump) dsz sz @C:/bbs/files.lst (Indirect file list) 22 ────────────────── Dsz Interrupt Keys: ────────────────── Ctrl-Break Terminates the transfer in progress. ALT-N Abruptly terminates (NUKES) the transfer in progress. Ctrl-X Typing a dozen Ctrl-X characters to another ZMODEM program terminates ZMODEM operations. ALT-F Skips the current file in ZMODEM transfers. ALT-B Cancels the current ZMODEM session. ───────────────────── ENVIRONMENT VARIABLES: ───────────────────── The following DOS environment variables may be set to modify DSZ operation. DOS environment variables are set by giving a command to DOS. EXAMPLE: set DSZPORT=2 These DOS "set" commands may be placed in your AUTOEXEC.BAT file or given just before you run your communications program. DIRRX (Registered copies only.) Specifies the directory to receive (download) files. If the sting in DIRRX ends with "/", directory and/or disk designators in the incoming pathname are stripped, and only the stem (name and extension) is used. Otherwise, if an incoming file has an absolute pathname, the incoming pathname is used. EXAMPLE: set DIRRX=C:/rxdir/ dsz rz -r EXAMPLE: set DIRRX=B:/ The DOS "set" command defining the receive directory may be placed in your AUTOEXEC.BAT file. Make certain there is enough environment space to hold this value. Confirm this by typing "set" to the DOS prompt and verifying the DIRRX value is listed correctly. DSZFILES May contain a list of up to 9999 pathnames to transmit, with entries separated by spaces. If present, DSZFILES is used in place of a normal command line list of files to send with the sb and sz commands. EXAMPLE: C>set DSZFILES=file1 file2 file3 *.c C>dsz port 2 handshake on sz -rr In practice, this string would be built up by a calling program and passed to DSZ with a "spawnvpe", "execvpe", or similar subroutine call. 23 SEE ALSO: Pathname list specification @C:files.lst DSZLOG log file to receive entries for files sent and received. (Default null). Sample entries: Z 46532 38400 bps 3324 cps 0 errors 66 1024 DSZ.COM 1177 Z 124087 19200 bps 1880 cps 0 errors 6 1024 MXY.TMP 1177 Transfer times are based on the DOS time of day clock and have up to two seconds' uncertainty. As with all protocol throughput reports generated by Omen Technology programs (and contrary to the false claims of some critics), DSZ's throughput figures for ZMODEM, Kermit, and True YMODEM(TM) transfers do not take "credit" for pathname and/or protocol overhead characters. DSZ's throughput reports do not include the time required to send the pathname. This understates the true time required to transfer files, but the time required to send the pathname often depends on the alacrity of the operator, and thus does not always reflect the performance of the protocol itself. Transfers measuring less than one second are reported as having 9999 characters per second throughput. The unlabeled numeric field after the error (retry) count is the number of flow control stoppages encountered sending the file. This number gives an indication of flow control restrictions (overloaded networks, etc.) encountered during the transfer. The last numeric field before the file name is the YMODEM block size or ZMODEM subpacket length used for the last block in the file. The last field is the serial number of the other program, or -1 if this information is not available. The code letter indicates the type of transfer, Z (ZMODEM), S (X/YMODEM), R (X/YMODEM), E (error), or L (transfer terminated by loss of data carrier). WARNING: If DSZ encounters a loss of carrier or other fatal error condition before a file COMMENCES transmission, a log entry may not be made. DSZOPT (Registered copies only) String containing default options for DSZ file transfers. Options are optional modifiers to the DSZ sz, rz, sx, rx, sb, rb commands. A T may be appended to the string to force DSZ to exit after it has recognized a ZMODEM AutoDownload(Tm) request. An 8g may be appended to the string to make BBS (ANSI) graphics the default for DSZ's t command. The ability to preset these options is especially helpful for controlling ZMODEM automatic downloads from DSZ's t 24 command. EXAMPLE: C>set DSZOPT=r Enables DSZ's Intelligent Crash Recovery(TM) as a default. Let's say you wish ZMODEM crash recovery, and BBS "graphics" for the DSZ term function: C>set DSZOPT=r8g WARNING: Do NOT include "ena" or any other commands in the DSZOPT string. With the exception of the "8g" mode, only **options** may be placed in the DSZOPT string! (Options are the letters that modify the sz, rz, sb, etc. commands. In "rz -r", "r" is an option.) MAXBYTES Maximum number of bytes allowed for transfer. If this number is exceeded, DSZ skips the offending files (ZMODEM) or aborts remaining files in the batch (YMODEM). DSZPORT Default communications port override, default 1. EXAMPLE: C>set DSZPORT=2 ZONE sets the z numeric parameter to the number of minutes the current local time lags GMT time. PDT or MST corresponds to 420. PST corresponds to 480. EXAMPLE: C>set ZONE=420 ────────────────────────── 1. IN CASE OF DIFFICULTY: ────────────────────────── If you have difficulty getting DSZ to work, start with the following command to DSZ, given directly from the DOS prompt, without running any TSR or other COMM program: dsz port 1 speed 2400 d t Type it exactly as it appears above; do NOT use upper case. (Change the port number and speed as necessary. Use only COM1 or COM2 for testing.) This connects you to the modem. Dial a bulletin board by typing AT commands to the modem ("ATDP621-3746 <enter>") to make it dial the BBS. Log in as usual. Then, request a ZMODEM download of a file you don't already have. The file will download automatically, you don't have to do anything. This procedure verifies the correct operation of DSZ. 25 ──────────── 1.1 LOCKUPS ──────────── 1.1.1 Insufficient Memory DSZ complains when it detects insufficient memory to operate. When calling DSZ from another program, there may be ALMOST enough memory for proper operation, but DSZ locks up during a transfer or the calling program freezes after DSZ displays the "DSZ Finished" message. Sometimes there is a message about insufficient memory, sometimes just a lockup and no message. To verify this problem, call CHKDSK from within your comms program (not from DOS!) by defining it as an external protocol. If you use an interface program (Hotkeyz, Prodoor, etc.), you must call CHKDSK from that program, as those programs also reduce the memory available to DSZ. CHKDSK should report at least 64k free memory. If less memory is reported, reduce the size of the COMMS program's capture buffer, or reboot the system with fewer/smaller device drivers and TSR programs. Calling DSZ directly from the comms program instead of from an interface also saves memory. 1.1.2 Environment TOO BIG A large environment may cause DSZ.COM to lockup. The size of the environment (the amount of text you get when you give the DOS "set" command) is subtracted from the data space available to 8086 C programs. This can be a problem with DSZ.COM, whose 8086 tiny model limits code, data, stack, and environment to 64 kb TOTAL. If DSZ.COM complains about the environment being too big, you should correct the problem. Use DSZ.EXE (compiled with 8086 small model) to alleviate this problem. 1.1.3 Bad COMM Port Configuration DSZ is fastidious about which interrupt vectors it takes over. Unlike some programs, DSZ uses only the correct interrupt vector for its interrupt service routine. (This allows multitasking.) DSZ obtains and releases this vector with standard DOS function calls. This allows multi line operation under DESQview and other multitasking systems. Incorrectly configured serial ports that work with programs that pig out both IRQ3 and IRQ4 will lock up with DSZ. If DSZ locks up the machine as soon as it tries to send or receive data, this is usually the fault. Make sure the comm port is strapped correctly; COM1 uses IRQ4, COM2 uses IRQ3. DSZ will lock up if the comm port is not properly set up. In addition, DSZ will not work properly if two devices are connected to the same IRQ line, even when some other programs (that don't use interrupts as intensively) do work normally on the same machine. 26 COM3 and above are not widely standardized. If you have problems with COM3, chances are your "COM3" is non standard. 1.1.4 No Carrier Detect If you see a No Carrier Detect message, and you haven't lost the connection, you need to give the d command: dsz port 1 speed 2400 d t Better yet, fix your modem cable or modem to allow proper operation of the Carrier Detect signal (CD)! Some BBS and/or "door" programs hang when the program (such as DSZ) they call returns with a non 0 exit status. Please refer to the "EXIT STATUS" chapter of the document for more information. 1.1.5 DOS 3.x DOS 3.x systems may need to have a "STACKS = 8,256" line in CONFIG.SYS to prevent antisocial behavior. This is required on the NEC Multispeed, or if certain TSR's are used. 1.1.6 Perstor Controllers Several reports have been received indicating Perstor disk controllers interfere with data communications. Perstor is reportedly working on a fix. 1.1.7 IBM PS/2 Model 50Z Early samples of this machine have a design error on the motherboard that causes comms programs to lock up the machine. Replacing the motherboard with a correctly functioning unit from current production corrects the problem. The part number of the replacement PS2/50 Z motherboard is 35F5928. (Information provided by John M. Choma 73047,3566) U.S. IBM has stonewalled on this issue, but in December 1988 agreed to replace the defective motherboards under warranty. 1.1.8 Brain Damaged UARTS Omen Technology has received reports of problems with buggy 8250 type UART integrated circuits in Leading Edge modem boards, serial port interfaces, and computers. The defective chip logic affects high performance software. Replacing the buggy chip with a newer chip (16450 or NS16550AN) corrects the problem. The UM82450 chip in the Zoom 2400HC also appears to cause problems. The NS16550AN is a pin compatible plug in replacement for 8250 and 16450 serial chips. Omen Technology software enables the FIFO buffer in the 27 NS16550AN to prevents loss of data from poorly written device drivers, TSR programs, etc. The NS16550AN has better electrical characteristics than the older UART chips. 386 and fast 286 machines should use the NS16550AN for best results. Omen Technology software has been written to allow time for the older UART chips to operate. However, there is a limit to how much the software can rearrange chip accesses without resorting to performance robbing wait loops. Some other software is not as forgiving of slow chips. Jameco Electronics at 415-592-8097 sells National NS16550AN chips mail order (credit card) in small quantities. Another source is Arrow Electronics at 800-932-7769 (516-467-1000). Be sure to ask for the NS16550AN. It's important to get the "AN" part, other versions won't do. PC BRAND at 800-722-7263 (in Illinois 312-226-5200) is selling I/O cards in which both UARTs are socketed, allowing them to be replaced by NS16550AN devices. Shipping and handling is included in their $45 price. (From Roger 1.1.9 Hough) 1.1.10 Everex Internal Modems Numerous reports have been received concerning difficulties with Everex modem cards. Some of these cards contain buggy 8250 chips which are not up to the demands of full duplex streaming protocols such as ZMODEM. Replacing the buggy 8250 chip with a 16450 (or better yet NS16550AN) chip corrects these problems. 1.1.11 Weird Iron A few machines, some with V20 CPUs, don't like DSZ.COM. We have not been able to repeat this; TeleGodzilla (using a V20) runs DSZ.COM without a hitch. Switching to DSZ.EXE has cleared up the problems on other machines. 1.1.12 Will the real YMODEM please stand up? Some XMODEM programs claiming to support YMODEM do not send or accept the YMODEM pathname block. 1024 byte XMODEM is XMODEM-1k, not the YMODEM defined by Ward Christensen in 1985 when he invented the term YMODEM. 1987 and later versions of YMODEM.DOC remind the reader of the official YMODEM definition, which has not changed since YMODEM's coinage in 1985. 1.1.13 286 and 386 Extended Memory Virtual memory disk caches and ramdisks using 80286 or 80386 extended memory require a kludge hardware reset of the CPU chip to return to the normal "real mode" after accessing extended memory. This interference to the interrupt response time causes lost characters on comm ports, and may be minimized by specifying shorter memory transfers. 28 Switching to a National NS16550AN UART chip helps tremendously, allowing transfers at 115200 bps instead of 9600 bps with a standard 8250. Please refer to the subchapter on "Brain Damaged UARTs". ──────────────────── BACKGROUND OPERATION: ──────────────────── Three DESQview description files are provided to demonstrate background operation with modest (66 kb window) memory requirements. DSZ uses tight C/ASM code, table driven CRC generators, and buffered receive and transmit for good performance in the background without hogging CPU cycles. On a QIC Labs 8 mHz PC-AT clone, DSZ can download files in the background (3 background clock ticks, 9 foreground clock ticks) with a throughput better than 9600 bps. 2S Prompts for file name(s) and sends them with ZMODEM protocol. File: 2S- PIF.DVP 2T Talks to the modem and allows manual YMODEM (F3) or automatic ZMODEM downloads. File: 2T-PIF.DVP 2A Like 2T, but using Quarterdeck's dvansi.com memory resident ANSI CRT device driver to process ANSI screen codes. File: 2A-PIF.DVP DS.BAT is the batch file used by 2A. These files are written for a port 2 local connection and \TMP directory, but may be modified to suit your requirements using the DESQview CP command. The W numeric allows DESQview to close the window after DSZ finishes, providing a pleasant user interface. Other DVPs, Scripts, and Batch files are available on the DESQView conference on the Sound of Music as DVDSZ20Z.ARC. Please consult the DESQview documentation for instructions on installation procedure for the DVP files. Operation at high speed (above 9600 bps) may require the DESQview "Optimize communications" performance Advanced Setup option. Newer versions of DESQview may require more "common memory" allocation (6-8 k bytes) to operate with DSZ. Some versions of DESQview do not operate properly with DSZ; DESQview 2.0 is known to work, and DESQview 2.25 is reported to have fixed bugs in intermediate versions. On 286 and 386 machines, some DESQview operations involve swapping memory contents with buffers in extended memory. As with extended memory ramdisks and disk caches, this causes errors with high speed communications. The considerations discussed in the "286 and 386 Extended Memory" subchapter apply here. Since this DESQview extended memory swapping is asynchronous with respect to DSZ's file transfers, "handshake slow" doesn't help. The solution is to force DESQview's memory swaps to use smaller blocks (with interrupts allowed between blocks) and/or use NS16550AN chips for the serial interface. 29 When running a comm program under DESQview or any related multitasking executive, DSZ must be called directly from the comm program, in the same window. DO NOT open a separate window for DSZ unless you were about to power down the computer anyway. With some communications programs, you can make the call, log in, and then exit (closing the window) without disconnecting the modem. At this time you can fire up DSZ with the "t" command to allow YMODEM or ZMODEM downloads in a small window. Example File: 2A-PIF.DVP Alternatively, you can start DSZ from the DOS prompt, then type "AT" commands to the modem to call the bulletin board. DESQview's "learn" facility may be helpful here. ─────── PROCOMM: ─────── DSZ may not operate properly when called from ProComm if ProComm has files open at the time. A number of reports have been received of problems running DSZ from ProComm Plus because of insufficient memory. Please refer to the subchapter on LOCKUPS. When running under ProComm's Host mode, failure to use the DSZ CON command may cause ProComm to lock up the computer, or at least interfere with file transfers, etc. EXAMPLE: DSZ CON sz %1 A number of third party programs have been developed to provide a congenial interface to DSZ if you have enough memory to spare. The POE, PCALL, DSZ_ZAP, and PROZ programs have been popular in interfacing DSZ to ProComm's editor gateway. These programs are available on many bulletin boards. Hint: the DOS PATH environment variable must include ProComm's directory to allow POE to locate all the POE files,. The POE files should be stored in the ProComm directory. Setting the "PROCOMM" environment variable is insufficient. ─────────────────── 2. ERROR MESSAGES: ─────────────────── COM2 1200 bps Carrier Detect enabled Handshake slow Command line = (commands) This is a normal message displayed to help resolve problems with incorrect batch files. The port number, speed, carrier detect ("enabled" or "DISABLED") and "handshake" indicate the selected mode of operation. 30 DSZ FINISHED! exit code = 0 This is DSZ's normal exit when at least one file has been transferred and no unrecoverable errors have been detected. If an error such as a failed file transfer had been detected, the exit code would be 1, or the value set in the Q numeric parameter. As the message implies, DSZ has done all of its processing, and has return the communications port and vector to its original value before displaying this message. If the computer locks up after this message is displayed, there's something wrong with the program that called DSZ, not with DSZ itself. Unknown Machine Type XX, 'a' parameter preset to 6000 indicates a ROM BIOS that does not follow the IBM specification for identifying the machine type. If your computer causes DSZ to display this message, you may set the a numeric parameter described elsewhere in this document. This message is generated before any commands are read, so do not be alarmed when you "discover" that setting the a parameter doesn't make this message go away. The a parameter does not affect ZMODEM transfers. Please send us a postcard or letter indicating the reported hex value for machine Type, name of the computer, and its speed so we can include that machine type in a future release. Need more memory to run DSZ or Abnormal program termination is displayed by the TurboC startup routine if DSZ is run in too small a memory partition. If you see this message, use a larger memory partition for DSZ or remove some memory resident programs. This message may also appear if the calling program fails to free memory before calling DSZ. No Carrier Detect is displayed when DSZ recognizes a lack of carrier detect signal from the modem. Most support calls concerning "No Carrier Detect" are caused by the user failing to tell DSZ to use the correct port. DSZ does not magically divine the COM port number; if the default COM1 is incorrect, DSZ must be told what port to use with the port command or the DPORT environment variable. No Carrier Detect may also be caused by a line disconnect, defective cable, or incorrect modem strapping. It may be disabled with the d command. Sometimes this is caused by setting the B parameter to too large a value. Garbage Count Exceeded Indicates ZMODEM has not detected a valid start of header in a reasonable number of characters. If DSZ becomes "stuck" on emitting this messages, it is possible the sending program may not be able to recognize and act upon transmission requests (ZROPS headers). The sending program should be corrected. In the meantime, setting a ZMODEM packet length with the "zmodem pl4096" ("l" is the small letter l) command will force the sender to wait for the receivers' progress reports. Permission denied comes from the Microsoft C Library. This is caused by attempts to modify a read only file or directory, or to create a file in a nonexistent directory. 31 A furtive flashing appearance of XOFF or FLOW during ZMODEM or YMODEM-g file sending signifies DSZ is responding to flow control restraint. This is normal operation when buffered modems or packet switched networks are used. ZMODEM's robustness and reliability allow creative users to transfer files over unusual multiple computer lash-ups, causing modem data lights and computer status displays to dance in unfamiliar rhythms. Output FLow Control Restraint RELEASED Indcates DSZ has not received a positive flow control signal (XON and/or CTS as specified by the handshake command) within the timeout specified by the S numeric parameter. This message may appear as the result of line noise. If it appears sonsistiently, it may indicate improper flow control settings, defective modem and/or cable, or (rarely) too small a value for the S numeric parameter. Not allowed to overwrite %s By default, DSZ will not overwrite an existing file. Use the -y or -n or -r option to overwrite/update existing files. 2.1 Got ZRPOS Got ZRPOS indicates the receiving program has detected a transmission error and has requested retransmission. In other words, ZMODEM is doing its job of detecting and correcting missing and garbled data. If this happens more often than observed line errors would indicate is reasonable, there may be a flow control problem in one of four areas: + Between the sending program and its modem. If using an interface speed higher than the transmission speed, or modem to modem error correction (MNP, LAPB, PEP, etc.), check that the modem and the sending program are configured for the same flow control methods. Omen Technology's software is faster than most other programs, and may expose flow control problems not seen with slower software. + Between the sending modem and the network. Correcting this requires "handshake both" to allow the sending program to honor both hardware (CTS) flow control from the modem and software flow control (XON/XOFF) from the network. + Between parts of the network. + Between the receiving modem and the receiving program. This can happen at high transmission speeds when the receiver has specified a large I/O buffer size with the B numeric parameter. Excessive interrupt latency from extended memory ramdisks or disk caches, and poorly written hard disk drivers also wreak havoc on streaming protocols but do not affect start-stop protocols (XMODEM, etc.). Problems with extended memory disk caches may cause errors at regular intervals; check the receiver's error messages. To work around these problems, give the "handshake slow" command to the receiver. 32 Byte NNNN retry M: <error message> These messages appear when the protocol has detected an error and is attempting to retransmit the garbled data. These are normal messages. 2.2 Serial Input Error: Line Status Register xx Serial Input Error: Line Status Register HH indicates a slow device driver, TSR program, or other software is disabling interrupts too long for the program to accept incoming data, and some characters are lost. A slow response to folow control also triggers this message. The value of the line status register is displayed in HEX. The following error conditions when present OR into the Line Status Register. 01 The Interrupt level circular buffer has been overrun. The remote did not respond to 's XOFF or hardware flow control, and continued to send characters after being told not to. This problem is alleviated by correct modem flow control configuration. 02 An 02 value for the LSR indicates Data Overrun. "Data Overrun" means the computer was not able to respond to an incoming character from the UART (modem) in time to make room for the next incoming character. Data Overruns are caused by poorly designed software (or ROM BIOS "firmware") locking out interrupts for excessive periods. These lockouts prevent the communications program from responding to the incoming characters quickly enough. To correct Data Overruns, correct the offending condition(s) to allow the communications program to operate properly. Common causes of excessively long interrupt lockouts ("critical code regions") are disk drivers (BIOS), window managers, disk caches, TSR programs, EGA/VGA board auto-select. Some BIOS programs are written without regard to their effect on high speed communications. Sometimes better versions of the offending BIOS programs are made available if enough users complain about poor performance. Interrupt latency caused by EGA/VGA board auto-select can be often corrected by disabling the board's Auto-Select. Other chapters in this document give suggestions for working around excessive interrupt latency, primarily the handshake slow command and use of the NS16550AN UART chip. Please refer to the "Brain Damaged UARTS" subchapter. 08 Framing Error generally caused by line noise or an incorrect transmission speed ("baud rate") or format (number of bits). Most protocols require 8 bits no parity (-8n) for proper operation. This is set automatically by Omen Technology programs, but other programs may not be so smart. 33 10 Break Interrupt generally caused by line noise or an incorrect transmission speed ("baud rate") or format (number of bits). 18 Framing Error and Break Interrupt (see above) in combination. This error may also be caused by defective 8250 UART chips. Certain internal modem cards have slow 8250 chips that do not operate properly with computers faster than 4.77 mHz. Replacing the 8250 with a NS16550AN is recommended. 2.3 Out of Environment Means there is not enough room in the program environment to accept more data. DOS prints this message when it cannot allocate more memory to accommodate a "set" command, such as "set dirrx=c:/downloads/". Try moving the "set" commands to the batch file that calls your comms program, or to your AUTOEXEC.BAT file. To increase environment, use the /E switch. The default is 160 bytes. An example for your CONFIG.SIS file: SHELL=C:COMMAND.COM/E:256 NOTE: Large environments may cause DSZ.COM to lockup. This is less of a problem with DSZ.EXE. 2.4 SLOW TRANSFERS Some users report slower than expected file transfers even when few or no errors are reported. Some possible causes are: If "handshake slow" is used, throughput may suffer. Try one of the other solutions to the "Line Status Register = 02" error problem discussed above. It may be possible to increase the modem's interface speed, say from 9600 to 19200 bps. Bad phone lines will silently slow MNP modems, sometimes without any error indications. Of the modems disconnect fairly often you should suspect marginal phone line conditions that are begin "covered up" by the MNP. The other ZMODEM may have a parameter or option is use that acts to slow the transfer under certain conditions. 34 ───────────────────────────────────── JAN-22-1990: ZMODEM-90(TM) EXTENSIONS: ───────────────────────────────────── Receiver specified window size: The -Wn option operates similarly to the -wn option. The -Wn option is specified to the receiver, which sends this information to the sender. Pro-YAM, ZCOMM and DSZ versions beginning with Jan 22 support this. Specified extra escaped characters: The "zmtxesc" and "zmrxesc" allow extra characters to be escaped when sending (zmtxesc) or receiving (zmrxesc). Zmtxesc is effective sending to any ZMODEM program. The sz commands in Omen products after Jan 22 1990 except for DSZ.COM recognize incoming "zmrxesc" requests. TThe zmrxesc and zmtxesc string parameters consist of one or more printing characters corresponding to the control characters to be escaped. To escape NULL: set zmrxesc "@" Since DSZ does not support string parameters, a -Q<string> option unique to DSZ performs the same function as zmrxesc and zmtxesc. If the Q<string> option is used in DSZOPT, it must be last. To escape NULL: dsz sz -Q@ file.ext MobyTurbo(Tm): MobyTurbo optimizes throughput on ZIP, ARC, and similar files over paths that support YMODEM-g (or would except for random errors). MobyTurbo cannot be used with most types of software flow control (or "handshake both"). Activate MobyTurbo with the -m option to one or more of: sz, rz, or adlopts. LOCK OUT MobyTurbo with the -M option. -M is effective until the next "call" command. Use -M in situations when the sender has -m turned on and YAM's check fails to discover path conditions that preclude MobyTurbo. ────────────────────── MAJOR REVISION HISTORY: ────────────────────── The ZMODEM "Slow Send" mode inserts a brief pause after each subpacket when invoked with the -F option, or automatically when the "sz" command detects failing flow control. The zmodem F numeric parameter (default 1) sets the pause in tenths of seconds. 4-24-89 The -rr option has been improved. Long file compares are done in two stages to save time when the first portions do not match. Diagnostic code and undocumented commands have been removed to decrease the program size. DSZ now defaults to "handshake both" if the speed is greater than 2400 and the clear to send signal is high when DSZ selects the comm port (was "handshake on" in 3-19). The 4-18 version introduces ZMODEM variable length headers of up to 16 bytes 35 information field instead of the previous fixed 4. Selection of variable length header capability is automatic and downward compatible. Variable length headers allow future extensions to ZMODEM's capabilities. ZMODEM Crash Recovery now understands the -rr option to compare the CRC-32 of the assumed common file segment before continuing an incomplete file transfer. The "zmodem R" numeric parameter may be set to limit the number of bytes in the files that are compared; the default R value of 0 allows all of the file to be compared, an R value up to 32000 (up to 2 billion on 32 bit flavors) limits the comparison to the first R bytes of the two files. The ZMODEM -rr option is supported by Omen Tech versions April 18 1989 and later. When ZMODEM Crash Recovery detects incompatible source and destination file contents, the destination file is now truncated to zero length before proceeding with the transfer. Crash Recovery requires the destination file to be no longer than the source file. Error reporting on unregistered copies has been enhanced to point the user to solutions described in the relevant chapters in DSZ.DOC. 3-18-89 In order to work around a bug in the new TCOMM bbs, DSZ now defaults to "handshake on" if the speed is greater than 2400 and the clear to send signal is high when DSZ selects the comm port. The "o" command has been added to disconnect the modem after a terminal session: "dsz t o" disconnects the modem when the terminal session is completed. The "P" (capital P) numeric parameter (q.v.) has been added to display and control the UART fifo on some clone chips. Handling of the Ctrl-Break vector has been changed so an untimely keyboarded Ctrl-C or Ctrl-Break will not hang DOS. 2-15-89 DIRRX is enabled for BBS registrations (8xxx numbers). Logic has been added to simulate transmit interrupts on chips that have problems in this area. The "A" command does not require registration. An interaction between ONAME= or PREFIX= and the file count display has been removed. Time/date conversion routines have been enhanced to deal with files with missing dates. The "v" command has been added to allow bbs programs to interrogate DSZ's serial number. 2-06-89 A spurious error message at the completion of YMODEM downloads with a download directory specified on the command line has been eliminated. 2-05-89 DSZ now returns a non 0 status unless at least one file has been transferred. An inappropriate pathname/disk specifier check on specified download directories has been removed. Previous versions: Added the "A" command to prevent pcAnywhere host mode from locking up DSZ. SlugBait logic has been simplified, reporting any failed file transfer where any of the last 1K of the file was sent with Q status. 36 Introduced ZMODEM RLE compression with the -Z option. (registered DSZ copies also accept "Z" in the DSZOPT environment variable.) ZMODEM RLE compression packs runs of the same character in two or three character sequences. Compression is useful for screen dumps, uncompressed workspaces, compiler listings, and other files rich with strings of repeated characters, but not .ARC, .ZOO and other compressed files. Compression percentages range from -1 per cent for already compressed files to more than 1000 per cent (10x speedup!) for the Personal Computing text file benchmark(!). When sending to programs that do not support ZMODEM compression, the -Z option is ignored. The -Z option is effective when specified to the sending program only. Good news for tired frog stompers! The ZMODEM rz/sz programs are now available in a VMS C flavor. The VAX/VMS source files are contained in the RZSZ.ARC (RZSZ.ZOO) archive file. "Handshake slow" has been added to disable the RTS signal to the modem while writing to disk, even if the interrupt buffer is not chock full of bytes. This should help systems with excessive interrupt latency on disk writes. Setting the v (verbose) parameter to 1 or greater causes serialized copies to ring the bell when a transfer is done. DSZ.DOC has been extensively rewritten and reorganized. DSZ now supports the advanced buffering of the National NS16550AN and Intel 82510 serial interface devices. Please refer to the subchapter on "Brain Damaged UARTs". 37 38