Title: Config.sys Options Configuring your DOS system for use: ------------------------------------ When booting DOS, you will find it only supports a subset of the devices available on many computers. To support additional devices and advanced features, device specific driver and memory resident software most be loaded. This allows the kernel to be easily extended to support hardware not presently available and take better advantage of installed hardware without wasting resources on computers lacking it. This software is generally loaded during the kernel initialization phase, with details describing what to load expressed in the file CONFIG.SYS. The FreeDOS kernel will first look for a file named FDCONFIG.SYS, should it exist, it will will be used instead of CONFIG.SYS; this allows the FreeDOS kernel to coexist and be configured differently than another DOS kernel. There are additional options available to adjust other aspects of the kernel's behaviour. Note: some options listed below are FreeDOS specific and will not work when using other/older DOS kernels. Below is list of all documented FreeDOS config.sys supported options; additional undocumented options may exist but are not meant for normal usage. BREAK Usage: break=on|off Set extended Control-C/Control-Break checking to on [default] or off. When set to on, the kernel will perform the check (and invoke current handler if pressed) prior to most int 21h calls. When set to off, the kernel only performs the check on I/O calls using standard streams. Example: break=off BUFFERS BUFFERSHIGH Usage: buffers=nn[,m] where nn is in range 1-99 & m is in range 1-8 Memory buffers used by the kernel; primary[,secondary] The secondary buffer option is available for compatibility with other DOS kernels, but is ignored by the FreeDOS kernel. In MS DOS, a secondary buffer can used to read-ahead data. FreeDOS does not do this. Buffers are stored in HMA by FreeDOS, unless you select nn to allocate more buffers than fit in HMA. If nn is smaller, unused HMA space will be used for further buffers until something else allocates the HMA space for something else. Even then, at least nn buffers will always be available. You can set nn to a negative value to disable the use of unused HMA space: BUFFERS=-10 only uses 10 buffers, further free space in the HMA will just stay unused. Because the buffers can use the HMA anyway, BUFFERSHIGH does the same as BUFFERS for now, but shows a note about that to inform the user that it does not use UMB. Example: buffers=20 COUNTRY Usage: country=nnn[,[mmm][,[d:][path]file]] Enables/sets international features of DOS by selecting a country code and (only with the unstable / devel kernel) optionally also a codepage and country file. The stable kernel only uses the nnn value. For full support, use the unstable / devel kernel. You also need a COUNTRY.SYS file for the latter, while the former ignores the filename argument and only sets date/time/number formats, using values compiled into the kernel for a few common countries. It does not set sort order and upper/lower case translation tables. NLSFUNC can only be used with the unstable kernel. nnn is country code (001==US) mmm is code page (437 is default, 850 is updated form, 1252 for Windows) [drive][path]file specifies file with country specific data Example: country=001,850,C:\FDOS\BIN\COUNTRY.SYS DEVICE Usage: device=[d:][path]file [options] Load the device driver specified by d:path\file (into conventional [low 640KB] memory). The options are for the driver itself; refer to documentation that came with your particular device for supported options and their usage. Example: device=himem.sys DEVICEHIGH Usage: devicehigh=[d:][path]file [options] This is just like device= statement, except it attempts to load the device driver into high memory first (failing that it should load it in conventional memory). Note: The order you load devices may have a large impact on amount of free memory available. In general try to load large (in memory usage) programs into high memory first. Important: You should have a high memory manager such as FDXMS or HIMEM installed (prior device=FDXMS.SYS or device=HIMEM.SYS) before using this option. Example: devicehigh=xcdrom.sys /D:FDCD0001 DOS Usage: dos=high|low,umb|noumb Indicates whether the kernel should try to load itself into high memory or only conventional (low), and whether to link upper memory blocks in with normal memory or not. Note: only one set need be given, ie dos=high and dos=noumb are ok. Important: if you specify dos=high[,umb|noumb] then you must also load a high memory manager (first), ie FDXMS or HIMEM Example: dos=high,umb Example: dos=low,noumb DOSDATA Usage: dosdata=umb Try to load kernel data into Upper Memory Blocks; effectively same as using the [name]HIGH variant of kernel parameters, such as fileshigh, lastdrivehigh, and stackshigh (does not effect drivers loaded using device= or install=). Example: dosdata=umb ECHO Usage: ECHO Message to be displayed to user. ECHO displays (echos) its arguments to the console during config.sys processing when device drivers are loaded (when DEVICE= lines are executed). Example: ECHO loading driver 1 device=Driver1.sys ECHO driver1 successfully loaded EECHO Usage: EECHO Message with ANSI Escape Sequence EECHO allows for echo-ing ANSI Escape Sequences (redefines keyboard input for example). Use a dollar sign ($) to represent the ANSI Escape character. Note: requires an ANSI driver like NANSI loaded prior to use. Example: EECHO feeling $[33;44;1m blue :-) FCBS Usage: fcbs=nnn where nnn is in range 1-255 Sets the number of File Control Blocks to reserve room for. As file control blocks have been replaced by file handles (see files) and FreeDOS dynamically simulates FCBS from the handle data as needed, nnn is simply ignored by FreeDOS. Example: fcbs=4 FILES FILESHIGH Usage: files=nnn where nnn is in range 8-255 (default 8) Specifies how many files allowed open at once (reserves memory necessary to support opening this many files). Note: there are other restrictions, so a given program may not be able to actually open this many A good number is 20, though some programs suggest/require 30, 40, or even 255 Example: files=20 IDLEHALT Usage: idlehalt=n where n can be -1, 0, 1 or higher (default 0) Activates built-in kernel energy saving functionality if n is not 0. Value -1 enables all hooks, 1 enables only "safe" hooks, CPU halted only if kernel is waiting for CON char device input. Further hooks for n=-1 and n>0 depend on the kernel version: In addition to the safe hooks, other hooks can get activated, for example one for int 0x2f, ax=0x1680 "release time slice". Note: In rare cases, entering or leaving HLT mode (which causes big changes in CPU power consumption) can cause crashes if cheap power supplies or mainboards cannot properly filter the transients. Underclocking the whole system may help. Linux always does a few HLT at boot time, to force a hang on buggy systems early (boot with no-hlt to disable HLT). P90 may have buggy HLT? www.tavi.co.uk/ps2pages/ohland/halt.html INSTALL INSTALLHIGH Usage: install=[d:][path]file [options] Load the program specified by d:path\file. Generally used to load TSR (terminate and stay resident) programs with a minimal environment block. The options are for the program itself; refer to documentation that came with your particular software for supported options and usage. Example: install=nansi.com KEYBUF Usage: keybuf=n[,m] where n is in 0xac-0xde or 0x106-0x1de range and m is max 0x200 Relocate keyboard buffer from the default location at 0x40:0x1e-0x3e to 0x40:n-m. The buffer must be more than 32 bytes and must not touch offsets 0x100-0x105. Default for m is "next multiple of 0x100 after n". Note: Some BIOSes store data in the 0xac-0xff area. BASICA will use the 0x106-0x120 area. Other hardware, drivers or apps can collide with KEYBUF, too, so use it at your own risk. A reasonably safe choice should be "keybuf=0x140,0x1c0". LASTDRIVE LASTDRIVEHIGH Usage: lastdrive=x where x is last drive letter available for use; A-Z Example: lastdrive=z MENU Usage: menu [text] where text is the text you want to be shown while running config.sys. Menu displays a menu while running config.sys. Use menudefault to set a time delayed default option. Lines that begin with 1? will only be processed if the user presses 1. Lines beginning with 23? will be loaded if the user presses either 2 or 3. Options other than 0 can only be selected if at least one "numbers?" line actually uses them, as shown in the example below. Example: menu Please Select Configuration: menu menu Option 0 basic stuff only menu Option 1 CD-ROM menu Option 2 TROUSERS menu Option 3 CD-ROM and TROUSERS 0?echo you selected option 0 13?device=xcdrom.sys /D:FDCD0001 23?install=trousers.com MENUCOLOR Usage: menucolor foreground[,background] Use Menucolor before the menu config command, to create a full screen menu which supports the arrow cursor keys. The following colors can be used for foreground and background: 0=Black; 1=Blue; 2=Green; 3=Cyan; 4=Red; 5=Magenta; 6=Brown; 7=Light Gray The following colors can only be used for the foreground: 8=Dark Gray; 9=Light Blue; 10=Light Green; 11=Light Cyan; 12=Light Red; 13=Light Magenta; 14=Yellow; 15=White. If you do not use MENUCOLOR, the menu will not be full screen, so some of the BIOS, bootloader and kernel init messages (list of drives, version info...) stays visible. To change the colour to white text on blue, use the following: Example: menucolor 15,1 MENUDEFAULT Usage: menudefault=defaultoption,delay where delay is the delay time in seconds and defaultoption is the used standard option if the delay time is over. Menudefault sets a time delayed default option for a config.sys menu: If no key has been pressed during [delay] seconds, the default choice is activated. Pressing a key stops the countdown, the kernel will wait infinitely for the user to make a selection. Note that some virtual machines like Bochs can have broken (too fast) timing. Example: menudefault=0,5 NUMLOCK Usage: numlock=on|off Set the keyboard number lock to on or off. Example: numlock=off REM Usage: rem Your remarks! This provides the ability to place comments within the configuration file. The text following the rem until the end of the line is reached is ignored. This may also be used to temporarily disable loading a particular device or other option. A synonym for REM is the semicolon, see the examples. Example: REM DOS=HIGH,UMB Example: ;DOS=HIGH,UMB SCREEN Usage: screen=xx Switches into videomode xxx (INT10/11xx/000) where xx should be 0x11 for 8x14 font (28 lines VGA, 25 lines EGA) or 0x12 for 8x8 font (43 lines EGA, 50 lines VGA) or 0x14 for the default VGA font (25 lines VGA). Some newer graphics cards may not have 8x14 fonts in the BIOS. In that case, a driver can be loaded to load a suitable font in RAM, but SCREEN=0x11 should not be used. If xx is less than 15 (0x0f), it is treated as screen mode number, for example 1 for CGA 40x25 color text or 7 for monochrome text. Example: SCREEN=0x12 SET Usage: set ENVVAR=value Sets the environment variable to provided value. Example: set HOME=C:\home\me SHELL SHELLHIGH Usage: shell=[d:][path]file [options] Indicates the shell to use; often used to alter COMMAND.COM's behavior. Note: it is command.com that processes AUTOEXEC.BAT; by using the shell option, you can get command.com to process a differently named file (such as FDAUTO.BAT for coexisting with another DOS using different configuration options) or run a completely different command interpreter such as 4DOS or a (unix) sh variant. Example: shell=C:\4DOS.COM /E:256 /P Example: SHELL=C:\FDOS\bin\command.com C:\FDOS\bin /E:1024 /P=C:\fdauto.bat STACKS STACKSHIGH Usage: stacks=nn,mmm where nn is in range 0,8-64 and nnn is in range 32-512 Changes number and size of hardware interrupt stacks available nn is number of different stacks and mmm is size in bytes of each one In some cases you can use "stacks=0,0" to use only standard stacks instead of letting DOS allocate extra stacks for hardware interrupts. Example: stacks=16,256 SWITCHAR Usage: switchar=c Sets the default switchar to character c. Where c is a single character that is used to indicate a command line parameter is an option switch. The default is a forward slash (/). Note: This simply sets the value returned by a get switchar query, it will not effect programs that use hardcoded switch characters. The switch character is the sign used to mark options, for example the "/" in "DIR /w". Good values: "/" and "-". Example: switchar=- SWITCHES Usage: switches=/E[:xxx] /F /K /N /W Adjusts boot time processing behaviour. /E specifies how to handle moving of EBDA (Extended BIOS Data Area), if a size in bytes is specified [xxx, in range of 48-1024] then the EBDA will be moved from the top of conventional memory to a lower address (allowing for potentially larger free block of conventional memory if video memory at A0000 is available). without a size, the EBDA will not be moved /F skips the delay checking for F5/F8 keystroke before processing config.sys [equivalent to SYS CONFIG skipconfigseconds=0] F5 and F8 are only processed if pressed before DOS boots but after the keyboard is set up - right moment is easy to miss. /K forces treating of keyboard as 86 key keyboard, not 102/105 key. Might be useful with BIOSes or drivers which have no or broken handling for 102/105 key keyboards. /N disables F5/F8 support [equivalent to kernel config (SYS CONFIG, run SYS CONFIG /? for explanations) skipconfigseconds=-1] F5 (skip config) and F8 (single step config.sys) are ignored. /W is NOT supported in FreeDOS. This option in MS DOS would set a flag for Windows 3.0 to skip loading wina20.386 from the root directory. VERSION Usage: version=x.y FreeDOS specific command to specify what DOS version to report. For a kernel with FAT32 support, 7.10 is a good choice. Otherwise, 5.0 and 6.22 are common values. FreeCOM command.com "ver /r" displays both the reported and the FreeDOS internal version numbers. Example: version=6.22 Advanced - FreeDOS specific CONFIG.SYS menu processing: ------------------------------------------------------- normal FILES=20 DEVICE=MyNetWorkDriver.sys '?' - ALWAYS ask if a single line shall be executed FILES=20 DEVICE?=MyNetWorkDriver.sys '!' - NEVER ask if a single line shall be executed, even if single stepping !FILES=20 !DOS=HIGH,UMB !BUFFERS=30 !DEVICE=MyNetWorkDriver.sys configuration management - you may compose several configurations, using following special commands: MENU MENU select your configuration MENU MENU use (1) for CDROM operation MENU use (2) for NETWORK configuration MENU use (3) to load neither CDROM nor NETWORK drivers MENU MENUDEFAULT=3,60 (configuration 3, wait 60 seconds) rem CDROM 1? device=CDROM.SYS rem NETWORK 2? device=MyNetworkDriver.SYS rem Menu items can only be selected if at least one line uses them: 3? echo Basic configuration selected Although this is different than MSDOS menuing possibilities, it allows for selecting from multiple options during bootup while remaining simple. It, however, does not allow for multi-level menuing based configuration schemes. It's also possible to combine menu options, to avoid writing thing every time again. constructions like 0?devicehigh?=cdrom.sys are also possible ("if menu option 0 chosen, ask if you want to load this driver") the selected configuration can be determined in AUTOEXEC.BAT in the environment variable CONFIG like if %CONFIG% == 0 echo configuration 0 selected however, if you have no MENUs in config.sys, then %config% has no value, thus resulting in "IF == 0 echo configuration 0 selected." (which causes syntax errors as there's nothing on the left side of == ) That's why you better use something like: if [%config%]==[0] echo configuration 0 selected. -or- if "%config%"=="0" echo configuration 0 selected. then if there is no menu you have: "IF []==[0] echo configuration 0 selected." (which will of course output nothing) thus my config.sys now looks like !files=20 !dos=high,umb !break=off !buffers=30 !screen=0x12 !lastdrive=z !shell=\command.com /p /e:512 /MSG MENU MENU 0 - SoftIce+HIMEM+Network (default) MENU 1 - SoftIce+HIMEM MENU 2 - HIMEM+EMM386 MENU MENUDEFAULT=0,0 01? DEVICE=C:\NUMEGA\S-ICE.EXE /TRA 3000 /SYM 400 012?DEVICE=himem.exe 01? DEVICE=UMBPCI.SYS 2? DEVICE=EMM386.EXE NOEMS 0?device=c:\ntclient\ifshlp.sys DEVICE=xcdrom.sys /D:MSCD000 Full Screen Menus (thanks to Rune Espeseth) Use MENUCOLOR=foreground[,background] to obtain a full screen menu where you can use the arrow keys. Example (note that box drawing characters are used that look strange in other character sets): REM *** This is the FreeDos Config.sys *** REM *** executed before autoexec.bat *** REM *** Set white foreground, red background *** menucolor=7,4 files=20 buffers=20 REM *** The Menu *** MENU MENU *-------------------------------------------------------* MENU ! My Menu - FreeDOS rules! ! MENU *-------------------------------------------------------* MENU ! ! MENU ! 1. Test with border ! MENU ! ! MENU ! 2. Another test... ! MENU ! ! MENU ! 3. Third choice ! MENU ! ! MENU ! 4. Fourth choice. ! MENU ! ! MENU *-------------------------------------------------------* MENU MENUDEFAULT=1,10 ( configuration 1, wait 10 seconds) REM 1st choice 1?ECHO You selected menu #1 REM 2nd choice 2?ECHO You selected menu #2 REM 3rd choice 3?ECHO You selected menu #3 REM 4th choice 4?ECHO You selected menu #4 2002-11-28 - Tom Ehlert 2003-07-15 - Bernd Blaauw 2003-09-18 - Bart Oldeman 2004-07-24 - Jeremy Davis ... 2008-22-01 - Fritz Mueller / Eric Auer