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Chapter 5. Internal Configuration Commands Introduction Chapter 4. explained how the AUTOEXEC.BAT and CONFIG.SYS files can be configured using the install program provided with X-DOS. The various commands which can be entered into the AUTOEXEC.BAT and CONFIG.SYS files, called the Internal Configuration Commands, were briefly introduced to help you decide which of these commands you should use during installation. In this chapter, a detailed explanation of the functions of all the internal configuration commands, and the various parameters and switches that can be used with these commands, is given. We suggest that after you have been using X-DOS for a while and are ready to start taking advantage of the full power offered by this operating system, you read through this chapter to get a good understanding of what you can do with the internal configuration commands. You may then use the install program to configure these commands in your AUTOEXEC.BAT and CONFIG.SYS files. Please note that you can also edit the AUTOEXEC.BAT and CONFIG.SYS files directly using the editor provided with X-DOS. 5-1 The ANSI.SYS Device Driver Purpose This device driver enables you to use ANSI escape sequences to extend your control of the screen and keyboard. ANSI escape sequences are tedious to use but they can create quite remarkable results when used properly. You can, for example, totally remap your keyboard, make fancy command line prompts, and much more. Type External Device Driver Syntax DEVICE=[d:][path]ANSI.SYS [Inserted in your CONFIG.SYS file Where d:path - is the drive and path to the directory in which the ANSI.SYS device driver resides. 5-2 BREAK Configuration Command Purpose his configuration command is used to set the circumstances under which [Ctrl]-C and [Ctrl][Break] are allowed to terminate program execution. Type Internal Configuration Command Syntax BREAK [ON | OFF] Where ON - specifies that BREAK mode will be turned ON. OFF - specifies that BREAK mode will be turned OFF. Remarks X-DOS's default setting is BREAK = OFF. Therefore, X- DOS only checks for a [Ctrl]-C or [Ctrl][Break] sequence during: * Standard input functions * Standard output functions * Print operations * Auxiliary operations To make X-DOS check for [Ctrl]-C and [Ctrl][Break] whenever it is requested set BREAK = ON in the CONFIG.SYS file. 5-3 BUFFERS Configuration Command Purpose This configuration command specifies the number of disk buffers that X-DOS allocates. A larger number normally increases the speed of disk intensive applications but also consumes more memory. Type Internal Configuration Command Syntax BUFFERS=xx [/E][/A] Where xx - is the number of buffers that X-DOS will allocate in memory. The default value for xx is 20 and must be in the range of 5 to 4,095. If you install X-DOS with the INSTALL command, the default value is set to 20. /E - tells X-DOS to put the buffers in extended memory /A - tells X-DOS to put the buffers in expanded memory Remarks: Please note that the buffers cannot be put in extended or expanded memory in the evaluation version of X-DOS. The Extended Memory allocation requires the XMS driver loader. Either the internal X-DOS XMS driver can be used (see below) or any other commercial product. Please note that though BUFFERS can be put in extended or expanded memory, some buffers have to remain in lower memory for DMA transfer. Examples: If you want to modify the BUFFERS size to 15, you should load the CONFIG.SYS file into ED and add the following line: BUFFERS = 15 5-4 The CACHE Configuration Command Purpose This configuration command increases the speed of disk intensive programs. It works best if you have extended memory or expanded memory available and normally gives better results than increasing the number of disk buffers. The cache only works on hard disks. Type Internal Configuration Command Syntax CACHE=/D0 [/D1] [/Mxxxx] [/E] [/A] Where /D0 - specifies that you want to cache the first physical disk, including all partitions on that disk. /D1 - lets you optionally cache a second physical disk if your computer has two hard disks installed. /Mxxxx - sets the amount of memory that CACHE will use for disk caching. You can specify a cache size up to 8,192K in size. You must enter the cache size in K (kilobytes). If you do not specify a CACHE size with the /Mxxxx parameter, CACHE automatically sets up a 64K cache. /E - sets up a disk cache in extended memory. /A - sets up a disk cache in expanded memory. Remarks: Please note that the CACHE command cannot be activated in the evaluation version of X-DOS. CACHE uses the memory you allocate for caching to store data most recently read from the disks. Additionally, CACHE reads more data into memory than is actually needed, forecasting which data may be needed on the following disk access. By doing this, there is a good possibility that the next data your program needs to read from the disk is already in the memory area of your cache. Since reading from memory is much faster than reading from even the fastest hard disk, a cache will dramatically improve the performance of disk intensive programs. The larger the cache, the better the probability is that the needed data is already in memory. You can only cache hard disks. The CACHE statement does not support caching of removable media. You must always specify at least one physical drive to cache or you will get an error message. It is important that you understand what a physical drive is. A physical drive refers to a complete hard disk, including all partitions on that hard disk. If your computer has one hard disk with three partitions set 5-5 up as drive C:, drive D:, and drive E:, you only need to specify the /D0 parameter after the CACHE statement to cache all of the three drives since they all reside on your first, and only, physical disk. If your computer has two hard disks installed and you choose to install a cache for both of them, the total amount of memory used by CACHE (as specified with the /Mxxxx parameter) will double. If you set up a cache for your hard disk(s), you may want to reduce the number of buffers you have set up with the BUFFERS statement since CACHE essentially does the same job as BUFFERS but in a much more efficient way. By reducing the amount of buffers, you can save some precious memory. Just keep in mind that CACHE does not support floppy drives so you should not set the number of BUFFERS too low since this can dramatically decrease the performance on floppy drives. If you specify more memory for caching than is available in your system, CACHE will display an error message and remain un-installed. Since certain programs such as backup programs may have problems working with a cache in memory, X-DOS provides a way of disabling CACHE from the command line. The X-DOS cache is a write through cache which means that it will increase the speed of the reading process while not affecting writing operations. Examples: If your computer has one hard disk installed and you want to set up a cache of 2MB in XMS memory for your hard disk, you should include the following statement in your CONFIG.SYS configuration file: CACHE = /D0/M2048/E 5-6 The COUNTRY Configuration Command Purpose This configuration command sets the time format and date format for the selected country. Type Internal Configuration Command Syntax COUNTRY=xxx Where xxx - is the international telephone code for your country. Remarks: The default value for COUNTRY is 001 which is the international country code for the United States. The following list shows the countries supported by X- DOS: COUNTRY INT. CODE Australia 061 Belgium 032 Canada-French 002 Denmark 045 Finland 358 France 033 Germany 049 Italy 039 Israel 972 Middle East 785 Netherlands 031 Norway 047 Portugal 351 Spain 034 Sweden 046 Switzerland 041 United Kingdom 044 United States 001 5-7 The DEVICE Configuration Command Purpose This configuration command makes X-DOS install device drivers during start-up. Type Internal Configuration Command Syntax DEVICE=[d:][path]filename Where d:path - is the drive and path to the directory which contains the device driver you want to install. filename - is the name of the device driver to install. Remarks: Device drivers are normally used to control certain parts of hardware on your computer. X-DOS supplies you with three device drivers on the X-DOS disk. These drivers have the following functions: ANSI.SYS : is a console driver which can be used to enhance standard input and output. Since X-DOS already implements enhancements for standard input and output, this device driver is normally not required. VDISK.SYS : is the virtual disk driver which can be used to install disks in either conventional memory, extended memory, or expanded memory. Virtual disks are often referred to as RAM disks and are a much faster storage media than normal disk drives. You can set up several virtual disks, each of which can be a maximum of 16,384K (16 megabytes) in size. If you purchase certain hardware add-on products for your computer, you may have to install a device driver in the CONFIG.SYS file to use this product. Just include the name of that particular products device driver in your CONFIG.SYS file including drive specification and path and this driver will automatically be installed the next time you boot your computer. Examples: If you want to create a RAM disk in extended memory with the size 384K and assuming that the VDISK.SYS device driver is located in the C:\DOS directory then you should add the following statement on a separate line in your CONFIG.SYS file. DEVICE=C:\DOS\VDISK.SYS 384 /E 5-8 5-9 The DOS Configuration Command Purpose This configuration command will load the kernel of X- DOS in the High Memory Area. Type Internal Configuration Command Syntax DOS=HIGH Where HIGH - is the parameter for relocating the X-DOS kernel into HMA Remarks: Please note that the DOS relocation into HMA is not provided in the evaluation version of X-DOS. High Memory Area is only available on 286, 386 and 486 computers. It consists of the first 64K (- 16 bytes) of the extended memory area. This segment of memory has the particularity of being in extended memory but still being accessible in real mode, thus allowing it to be viewed as memory by DOS. By setting the DOS switch to HIGH, the kernel will attempt to detect the availability of the HMA and relocate itself in this portion of memory. It will leave in the low memory some data used by DOS that cannot be put in HMA. Upon activation of the DOS=HIGH switch, X-DOS will also activate the internal XMS driver, that manages the rest of the Extended Memory (see below). 5-10 The FCBS Configuration Command Purpose This configuration command sets the number of files that the file control blocks can open at one time. Type Internal Configuration Command Syntax FCBS=x Where x - is the number of files that the file control blocks can open at one time. The default value for x is 4 and must be in the range of 1 to 255. Remarks: File control blocks are used to control open files. Programs that use file control blocks to access files will have one file control block assigned to each open file. File control blocks were originally implemented in the first version of the MS-DOS operating system for compatibility with the old CP/M operating system. Now, programs mostly use the more powerful file handles to control open files. X-DOS, however, support file control blocks for compatibility with older programs. 5-11 The FILES Configuration Command Purpose This configuration command sets the number of file handles which can be opened at one time. Type Internal Configuration Command Syntax FILES=xxx Where xxx - is the number of file handles which can be opened at the same time. The default value for xxx is 20 and must be in the range of 8 to 255. Remarks: The default setting of FILES = 20 is enough in most cases but certain programs like accounting programs, database programs, and desktop publishing programs often need to be able to open a larger amount of file handles at the same time. If you encounter an error message, stating that there are not enough file handles available, you will have to increase the number of file handles with the FILES statement in CONFIG.SYS. You can do this either by using the X-DOS program INSTALL or by editing the CONFIG.SYS file and adding the FILES = statement. Examples: If you want to modify the number of file handles in the FILES statement to 30, you should load the CONFIG.SYS file into ED and insert a line with the following contents: FILES=30 5-12 The FKEY Configuration Command Purpose This configuration command is used to turn off the default X-DOS function key definitions. Type Internal Configuration Command Syntax FKEY=ON Where ON - enables the use of the default function key definitions and redefinition of function keys from the command line with the ALIAS command. Remarks: You can ask X-DOS to assign commands to some of the function keys and redefine function keys to execute different commands. You can even combine the [Shift], [Ctrl], or [Alt] keys with the function keys so you can define a total of 39 commands to be executed by the touch of a hot key. You may wonder why you can only define 39 commands, not 40 commands. The reason for this is compatibility. X-DOS does not allow you to redefine the [F3] function key, which is used by MS-DOS to recall the previous command. 5-13 The HISTORY Configuration Command Purpose This configuration command sets the amount of memory allocated for the command line history buffer. The history buffer allows you to recall and edit previously executed commands. Type Internal Configuration Command Syntax HISTORY=xxxx Where xxxx - is the number of bytes which will be allocated to the history buffer. The default value for xxxx is 256 and must be in the range of 256 to 2,048. Remarks: The default setting of HISTORY = 256 should be enough in most cases since this amount of memory can hold about 15 to 20 previously executed commands. You can increase the history buffer so it will be able to hold more than 100 commands. Just keep in mind that if you have to scroll through dozens of commands to find a particular command it would probably be faster to type it again. Also, when you allocate memory for the history buffer you are using precious memory which will not be available for application program. Examples: If you want to increase the amount of memory allocated for the history buffer to 512 bytes, you should load the CONFIG.SYS file into ED and insert a line with the following contents: HISTORY = 512 5-14 The LASTDRIVE Configuration Command Purpose This configuration command sets the last available drive letter X-DOS can access. You only need to change this if you plan to use the SUBST command or a similar utility. Type Internal Configuration Command Syntax LASTDRIVE=x Where x - is a character between A and Z, describing a drive letter. This drive letter will be the last available drive that you can access with X-DOS. Remarks: You can never set LASTDRIVE equal to a drive letter less than the number of drives that you have installed in your computer. If you do set the LASTDRIVE equal to a drive letter less than the number of installed drives, X-DOS will ignore this statement in the CONFIG.SYS file. Examples: If you want to set the number of available drives to 10 which is the drive letter J, you should include the following command in the CONFIG.SYS file: LASTDRIVE = J 5-15 The SHELL Configuration Command Purpose This configuration command sets the name and location of the primary command processor. It can also be used to specify the size of the environment of the primary X-DOS command processor, COMMAND.COM. Type Internal Configuration Command Syntax SHELL=[d:][path]COMMAND.COM [/P] [/E:xxxx] or SHELL=[d:][path]filename [params] Where d:path - is the drive and path to the directory in which the command processor is located. /P - is a parameter used by COMMAND.COM which makes the current command processor permanent. /E:xxxx - is the number of bytes allocated to the environment of the COMMAND.COM command processor. The default value for xxxx is 384 and must be in the range of 160 to 9,999. filename - is the filename of a new command processor. params - are any valid parameters used by the new command processor. Remarks: The SHELL command can be used for several purposes which are split into two main areas; using SHELL with COMMAND.COM and using SHELL with a new command processor. Using the SHELL command with COMMAND.COM allows the user to copy the COMMAND.COM file to a different location, i.e. a virtual disk, and tell X-DOS where to find it. Also, it is often used to set a different size for the environment. Since X-DOS lets the user set environment variables for some of its commands, and many application programs also use the environment, it may be necessary to use the SHELL command to extend the environment size. The second major purpose of the SHELL command is to install a new command processor which takes over the job of COMMAND.COM. Note that you can theoretically replace the X-DOS command processor with a command processor supplied by another vendor, such as the 4- 5-16 DOS COMMAND.COM from JP Software. However, please note that such products may not work with the second command overlay and the SHELL. As such we advise you to always use the X-DOS command processor. Examples If you want to relocate the COMMAND.COM file to the D:\DOS directory and make it permanent, and also want to extend the size of the environment to 512 bytes, you should include the following statement in your CONFIG.SYS file: SHELL=D:\DOS\COMMAND.COM /P /E:512 5-17 The TBOPCOD Switch Purpose This switch will force X-DOS to trap any bad opcodes. When enabled, if a bad opcode is encountered X-DOS will terminate the task and exit cleanly without hanging the machine. Type Internal Configuration Command Syntax TBOPCOD = [ON][OFF] Where ON - enables the TBOPCOD switch OFF - disables the TBOPCOD switch Remarks By default TBOPCOD is set to OFF in order to maintain compatibility with some DOS applications. Note that this command can only be used with 286 machines and above. 5-18 The VDISK.SYS Device Driver Purpose This device driver lets you to set up temporary, simulated disk drives in conventional memory, extended memory, or expanded memory. Type External Device Driver Syntax DEVICE=[d:][path]VDISK.SYS [mem] [/E] [/A] Where d:path - is the drive and path to the directory in which the VDISK.SYS device driver resides. mem - is the amount of Kilobytes of memory that you wish to allocate to the VDISK. The default is 64K. /E - tells VDISK to use Extended Memory (XMS) /A - tells VDISK to use Expanded Memory Remarks: Virtual Disks are much faster than hard disks since the data resides in RAM rather than on the disk. X-DOS's VDISK can take advantage of XMS Memory or Expanded Memory to store data. Note that, unlike MS-DOS's RAMDRIVE.SYS, X-DOS's VDISK only uses Extended Memory provided by the XMS driver, thus avoiding conflict with other programs that take over the extended memory resources. Examples: Suppose that you wish to have a VDISK of 1 MB of memory in Extended Memory, you would add the following statement in your CONFIG.SYS file: DEVICE=C:\DOS\VDISK.SYS 1024 /E 5-19 The VERSION Configuration Command Purpose This configuration command sets the DOS version that X-DOS should emulate. X-DOS emulates a DOS version of 3.3 as default. Type Internal Configuration Command Syntax VERSION=x.yy Where x - is the major version number that X-DOS should emulate. yy - is the minor version number that X-DOS should emulate. Remarks: Certain application programs and device drivers may look for, and expect, a certain version number of the disk operating system in order for them to execute. If they do not find an expected disk operating system version number, they will normally terminate execution and display an error message similar to "Wrong version number". To prevent any kind of version number problems, X-DOS provides the VERSION command. If for any reason, you decide to change the version number at boot time do not forget to reset it to 3.3 before loading the command processor of X-DOS. X-DOS has a data structure format similar to DOS 3.3 but has capabilities included in DOS 4.x and 5.0. The choice for 3.3 compatibility was made due to the reliability of this version and its subsequent popularity with many users. Examples: If you want to change the emulated disk operating system version number in your CONFIG.SYS file to the version number 3.10, then include the following statement in the beginning of your CONFIG.SYS file: VERSION = 3.10 5-20 The VIDEO Configuration Command Purpose This configuration command greatly increases the speed of screen updating in text mode. Type Internal Configuration Command Syntax VIDEO=ON Where ON - enables fast screen updating by allowing X-DOS to bypass the video BIOS when reading and writing to the screen. Remarks: If you choose to set VIDEO=ON in your CONFIG.SYS file, you should notice a remarkable increase in the speed with which text based programs display information on the screen. The only penalty this increase in speed brings is a slight delay in cursor positioning. If you are using a very fast VGA display card you will not need to use the VIDEO=ON option. However, for CGA, EGA and 8-bit VGA display cards the difference in speed is very noticeable. 5-21 The XMS Configuration Command Purpose This configuration command activates X-DOS's internal XMS driver. X-DOS's XMS driver is compatible with the HIMEM.SYS driver available with MS-DOS 5.0. It has the particularity of being directly integrated in the DOS kernel. Syntax XMS=ON Where ON - is the parameter for activating the X-DOS XMS driver Remarks: The XMS driver manages the Extended Memory the way EMS drivers manage expanded memory. The XMS driver allows real mode application programs to use extended memory in a cooperative and hardware independent manner. It also manages the A20 line that enables the use of the High Memory Area. If you relocate the X-DOS kernel in HMA, the XMS driver will be activated automatically. 5-22