--- name: "dos" section: "1" platform: "linux" package: "dosemu" version: "0.98.8-2" release: "Debian 2.2 (Potato)" platforms: ["linux"] url: "https://new.carta.tech/dos" --- # dos(1) run MS-DOS and MS-DOS programs under Linux ## NAME dos, xdos, dosexec, dosdebug - run MS-DOS and MS-DOS programs under Linux ## SYNOPSIS **dos** \[ **-ABCcdkVNXtsgKm234OU** \] \[ **-h** *level* \] \[ **-F** *file* \] \[ **-f** *file* \] \[ **-L** *dexefile* \] \[ **-u** *confvar* \] \[ **-D** *flags* \] \[ **-M** *size* \] \[ **-e** *size* \] \[ **-x** *size* \] \[ **-P** *file* \] \[ **-o** *file* \] \[ 2\> *debugfile* \] \[ **-I** *config-options* \] \[ **-U** *inpipe\[:outpipe\]* \] **dosexec** \[ **-ABCcdkVNXtsgKm234OU** \] \[ **-h** *level* \] \[ **-H** *dflags* \] \[ **-F** *file* \] \[ **-u** *confvar* \] \[ **-D** *flags* \] \[ **-M** *size* \] \[ **-e** *size* \] \[ **-x** *size* \] \[ **-P** *file* \] \[ **-o** *file* \] \[ 2\> *debugfile* \] \[ **-I** *config-options* \] dexefile \[ **-U** *inpipe\[:outpipe\]* \] **xtermdos** \[ **-ABCcdkVNXtsgKm234OU** \] \[ **-h** *level* \] \[ **-F** *file* \] \[ **-L** *dexefile* \] \[ **-u** *confvar* \] \[ **-D** *flags* \] \[ **-M** *size* \] \[ **-e** *size* \] \[ **-x** *size* \] \[ **-P** *file* \] \[ **-o** *file* \] \[ 2\> *debugfile* \] \[ **-I** *config-options* \] \[ **-U** *inpipe\[:outpipe\]* \] **dosdebug** **xdos** \[ **-ABCbdNtsK234O** \] \[ **-h** *level* \] \[ **-H** *dflags* \] \[ **-F** *file* \] \[ **-f** *file* \] \[ **-L** *dexefile* \] \[ **-u** *confvar* \] \[ **-D** *flags* \] \[ **-M** *size* \] \[ **-e** *size* \] \[ **-x** *size* \] \[ **-P** *file* \] \[ **-o** *file* \] \[ 2\> *debugfile* \] \[ **-U** *inpipe\[:outpipe\]* \] ## DESCRIPTION **dos** invokes the Linux dos emulator, also known as **DOSEMU**.\ *debugfile* is an optional file into which all debugging output will be redirected. **xtermdos** brings up **DOSEMU** in an **xterm** (or one of its cousins: **color\_xterm**, **ansi\_xterm**, or **rxvt**). It automatically detects the IBM VGA font, and the best **xterm** to run, and then runs the **xterm** with the proper parameters required to run **DOSEMU**. **dosdebug** is used to control or debug an already running **DOSEMU**. **xdos** starts **DOSEMU** in it's own X window. This is the same as **dos -X** **dosexec** starts **DOSEMU** and executes a DEXE file. This is the same as **dos -L** Although this program is known as the DOS *emulator,* it is actually a virtual machine for MS-DOS, allowing DOS and programs written for DOS to operate in an environment similar to a standard IBM PC/AT or compatible with an Intel 80x86 processor in real mode. **DOSEMU** provides emulation of such services as BIOS video, disk, keyboard, serial, and printer; CMOS memory for configuration information; a real time clock; memory allocation through the XMS 3.0 specification, EMS 4.0 and DPMI 0.9. Because **DOSEMU** is not really a DOS emulator, a copy of MS-DOS 3.3-7.00 is required. (Future versions of MS-DOS may run, but have of course not been verified. DR-DOS 6.0 has also been reported to work.) See the files *QuickStart,* *ChangeLog,* *doc/announce,* and the **Makefile** contained in the source distribution for information on how to configure, compile, and boot **DOSEMU**. ## KERNEL REQUIREMENTS At present, you will need Linux 2.0.28 or above with the SYSV IPC option (System V InterProcess Communication facilities, see [**ipc**(2)](/ipc/2.md)) compiled. SYSV IPC is an option in the configuration setup during a Linux kernel compile. Starting with dosemu version 0.64.3 *full feature dosemu* is the default. For details see *doc/README.vm86plus.* For a *low feature dosemu* you need to configure with --enable-novm86plus If you use 1.2.13, please upgrade to the latest stable kernel. At the time of writing, it was Linux 2.0.28, available with anonymous ftp at ftp.funet.fi in the directory /pub/Linux/kernel/linux/v2.0/, or at various mirrors all over the world. ## OPTIONS - *-A* boot from floppy disk A (does not need to be a real floppy disk, see below) - *-B* boot from floppy disk B (does not need to be a real floppy disk, see below) - *-C* boot from hard disk C (does not need to be a real hard disk or even a msdos filesystem, see below) - *-c* use direct Console video (must be at the console, requires that **dos** is suid root) - *-d* detach from current virtual console or tty and attach to the first free virtual console - *-V* use VGA specific video optimizations - *-k* use RAW console Keyboard (must be at the console) - *-F* Parse this config-script instead of /var/lib/dosemu/global.conf (you need to run as root on suid DOSEMU for this) - *-f* Parse this config-file instead of .doserc - *-u* set a user configuration variable. An **u\_** is prefixed to the name to avoid name clashes. This variable then can be checked in /etc/dosemu.conf or /var/lib/dosemu/global.conf to do some special configuration. - *-L* Load and start a DEXE file (special preconfigured bootable hdimage containing just one DOS application) - *-I* Parse the string behind *-I* with the same syntax as /var/lib/dosemu/global.conf or .dosrc such as - dos ... -I 'video { mda }' This is usefull if you just want to override a given configuration parameter temporary. You also may have a generic configuration by executing a script such as - dos ... -I "\`myconf.sh\`" where *myconf.sh* is a script writing the configuration to stdout. If you have an alternate configuration file besides .dosrc, - dos ... -I "\`cat myother.conf\`" will do the job. Note however, that you have to quote the parameter behind *-I* because it is expected to be *one* argument. - *-D* specify which Debugging messages to allow/suppress - *-h* dump configuration to stderr and exit (implicit sets -D+c). This is useful for debugging configuration files, you should use *-O* too to direct the +c type messages to stderr. \`level' can be 0, 1 or 2 and controls the amount of configuration parser debug output: No parser debug (0), parser loop debug (1), if\_else\_endif debug (2). - *-H* specify the dosdebug support flags, currently only \`1' is is reasonable. with *-H1* you force dosemu to wait until the dosdebug terminal has connected. Hence to debug a DOS session from the very beginning you first start dosemu with -H1 and then start dosdebug. DOSEMU will then lock before jumping into the loaded bootsector waiting for dosdebug to connect. Once connected you are in \`stopped' state and can set breakpoints or singlestep through the bootstrap code. - *-O* use stderr for output of Debugging messages - *-o* use this file for output of Debugging messages - *-M* set base memory to SIZE Kilobytes - *-m* enable internal mouse-support - *-P* copy debugging output to FILE - *-2,3,4* choose 286, 386, or 486 processor (BE CAREFUL! **DOSEMU** is not yet 32-bit clean, so if your program detects a 386 or 486 processor and uses 32-bit registers, it might be confused by BIOS functions. If you think this is happening, use -2 to force **DOSEMU** into 286-mode.) - *-U* define inpipe and outpipe for asynchronous control of **DOSEMU** from an other process. The format is (whithout white spaces between) - inpipe:outpipe where \`:outpipe' can be omitted. In the latter case no feedback from **DOSEMU** can be expected. For security reasons **DOSEMU** does not create the named pipes itself, so the user is responsible to set the permissions of the pipes correctly. Note that when using this options, the foreign process can control your **DOSEMU** session (such as entering keystrokes). This option should therefor only used by frontends (such as kdos), which first create the proper named pipes and then launch **DOSEMU.** A special control command ( *ack on* ) can be used to force **DOSEMU** returning handshake taggs via \`outpipe' such that the frontend knows when the control command has started or finished and wether it was successful. The format of this tagging is - SYN: \ - \ - ACK: code=n where *n* is 0 for success. A tiny control terminal, which can serve as example, is the supplied *dosctrl* programm. It takes just the two pipes as arguments and you may then enter control commands, which of them \`help' is the most important one;-) Note that *dosctrl* does not launch **DOSEMU,** you have to do it yourself. ## HARD DISKS **DOSEMU** supports four methods of supplying DOS with hard disks: - 1\. a virtual disk file residing on a Linux filesystem which emulates a hard drive. - 2\. direct access to an MS-DOS partition through a raw disk device (i.e. /dev/hda, /dev/hdb, /dev/sdX). - 3\. direct access to an MS-DOS partition through single partition access (i.e. /dev/hda1, /dev/hdb2, /dev/sdxx). You need to run the program **mkpartition** to enable **DOSEMU** to access your DOS-partitions with SPA. - 4\. access to a Linux filesystem as a "network" drive using the driver emufs.sys supplied with **DOSEMU** in commands/emufs.sys. This is explained more thoroughly in **QuickStart.** Configuration of **DOSEMU's** hard disk resources is done by editing **/etc/dosemu.conf** before running **DOSEMU**. Look at doc/README.txt. ## FLOPPY DISKS **DOSEMU** supports two methods of supplying DOS with floppy disks: - 1\. a virtual disk file residing on a Linux filesystem which emulates a floppy drive - 2\. direct access to a physical floppy through a raw disk device (i.e. /dev/fd0, /dev/fd1). This is also explained more thoroughly in **QuickStart.** Configuration of **DOSEMU's** floppy disk resources is done by editing the **/etc/dosemu.conf** before running **DOSEMU**. ## VIDEO **DOSEMU** may be run on any tty device. However, increased performance and functionality may be had by taking advantage of special features of the Linux console. Those running **DOSEMU** on the console may wish to investigate the *-c,* *-k,* and *-V* switches, explained more thoroughly in **QuickStart.** There is also some very brief documentation in the file etc/dosemu.conf, which can be copied to /etc/dosemu.conf and edited for your needs. In brief, proper use of the console device and the corresponding switches allows the user to view a DOS program in its original color and font, with none of the periodic screen update problems with the generic tty output code. ## KEYBOARD Those using **DOSEMU** on the Linux console may also wish to use the RAW keyboard support. This mode of operation, selected by the *-k* switch, provides the user with access to the entire keyboard accessible under DOS. Any combination of ALT, CTRL, and SHIFT keys may be used to generate the odd keycodes expected by many DOS programs. ## PRINTING The BIOS printer services are emulated through standard UNIX file I/O to a set of files, *dosemulpt1,* *dosemulpt2,* and *dosemulpt3,* corresponding to the DOS printer devices LPT1, LPT2, and LPT3. All characters sent to LPTx will be redirected to the file dosemulptx in the current directory. **WARNING!** **DOSEMU** does not keep the file buffers flushed; therefore, the state of these files is undefined until you actually exit the DOS emulator. Please excuse the inconvenience. ## DEBUG MESSAGES Debug messages can be controlled either at the command line or in the configuration file. Take a look at the documentation inside the config.dist file included with **DOSEMU** in the examples subdirectory, for debugging options. At the command line, you may specify which classes of messages you wish **dos** to allow. The syntax of this is **DOSEMU** takes an option "-D FLAGS", where FLAGS is a string of letters which specify which options to print or suppress. **DOSEMU** parses this string from left to right. \+ turns the following options on (initial state)\ \- turns the following options off\ a turns all the options on/off, depending on flag\ 0 turns all options off\ 1-9 sets the debug level, the higher, the more output\ \# where # is a letter from the valid class list, \ turns that option off/on depending on the \ \+/- state. *Message Classes:* d disk R disk read W disk write\ D int 21h C cdrom v video\ X X support k keyboard i port I/O\ s serial m mouse # default ints\ p printer g general c configuration\ w warning h hardware I IPC\ E EMS x XMS M DPMI\ n IPX network P Pkt-driver S SOUND\ r PIC T IO-tracing Any debugging classes following a *+* character, up to a *-* character, will be turned on (non-suppressed). Any after a *-* character, up to a *+* character, will be suppressed. The character *a* acts like a string of all possible debugging classes, so *+a* turns on all debugging messages, and *-a* turns off all debugging messages. The characters *0* and *1-9* are also special: *0* turns off all debugging messages, and *1-9* turns on all debugging messages, but set the debug level too. There is an assumed *+* at the beginning of the FLAGS string. Some classes, such as error, can not be turned off. In case you didn't redirect stderr, nearly all output to stderr goes to **/dev/null.** Some examples:\ "-D+a-v" or "-D1-v" : all messages but video\ "-D+kd" : default + keyboard and disk\ "-D0+RW" : only disk READ and WRITE Any option letter can occur in any place. Even pointless combinations, such as *-D01-a-1+0,* will be parsed without error, so be careful. Some options are set by default, some are clear. This is subject to my whim, and will probably change between releases. You can ensure which are set by always explicitly specifying them. ## SPECIAL KEYS In RAW keyboard mode (see the **-k** option), **DOSEMU** responds to certain key sequences as control functions. - ctrl-scrlock = show 0x32 int vectors - alt-scrlock = show the vm86 registers - rshift-scrlock = generate an int8 (timer) - lshift-scrlock = generate an int9 (keyboard) - ctrl-break = ctrl-break as under DOS. - ctrl-alt-pgup = reboot DOS. Don't trust this! - ctrl-alt-pgdn = exit the emulator Use \-\-\ to switch to another virtual console. ## MEMORY The XMS memory support in **DOSEMU** conforms to Lotus/Intel/Microsoft/AST extended memory specification 3.0. I have implemented all XMS functions except function 0x12 (Reallocate Upper Memory Block). While I have implemented the UMB functions, they are extremely stupid and will almost always act suboptimally. The next release of **DOSEMU** should have saner UMB support. **DOSEMU** 0.97 also supports EMS 4.0 and implements DPMI 0.9 (1.0 partially). ## LOGGING **DOSEMU** is able to log all use via [**syslogd**(8)](/syslogd/8.md). In the file */etc/dosemu.users* you may set the loglevel by means of the keyword *log\_level=value* Where *value* can be 0 (no logging), 1 or 2 (highest loglevel). Read *doc/README.txt* for more details. ## AUTHOR **DOSEMU** (comprised of the files **dos** and **libdosemu** ) is based on version 0.4 of the original program written by Matthias Lautner (no current address that I know of). Robert Sanders \ was maintaining and enhancing the incarnation of **DOSEMU** with which this man page was originally distributed. During about 4 years James B. MacLean \ was the restless leader of the dosemu team, implementation of DPMI (which made Windows-3.1, dos4gw, djgpp, e.t.c running) happened during his 'governement' and brought the project near to Beta-state. Now Hans Lermen \ is maintaining this funny software. ## BUGS There are too many to count, much less list. Please report bugs to the author. I'd also like to hear about which programs DO work. Just send me a note detailing what program (and what version) you are using, what works and what doesn't, etc. ## AVAILABILITY The most recent public version of **DOSEMU** can be ftp'ed from tsx-11.mit.edu in the /pub/linux/ALPHA/dosemu directory. If you want to keep up on private developer pre-releases, join the **DOSEMU** developer team - even just good detailed debug reports are all you need! ## FILES - */usr/bin/dos* The invoker program. - */usr/bin/xtermdos* The xterm wrapper (obsolete). - */usr/bin/xdos* The X version. - *$HOME/dosemu* Per user **DOSEMU** local directory. This will be created silently, if not existing. - *$HOME/dosemu/tmp* All temporary file creation happens here, we do not use /tmp anymore. - */var/run/dosemu.\** or - *$HOME/dosemu/run* Various files used by **DOSEMU** including debugger pipes. - - */var/lib/dosemu/\** or - *$HOME/dosemu/lib* Various files used by **DOSEMU** including diskimages and disk config files. This directory also holds the global configuration script *global.conf* for **DOSEMU** which then includes */etc/dosemu.conf* If */etc/dosemu.users* does allow it for a given user, then (in case of non-suid-root) *$HOME/dosemu/lib* will be taken instead of */var/lib/dosemu/\** and the user may have its completely own configuration. - */etc/dosemu.conf* Main configuration file for **DOSEMU**. which is included by *global.conf* - */etc/dosemu.users* or - */etc/dosemu/dosemu.users* Defines the access rights to **DOSEMU** on a per user basis and sets some vital configuration. This is the only fix-location configuration file, **DOSEMU** first looks for */etc/dosemu.users* and, if this is not found, for */etc/dosemu/dosemu.users .* Via the keyword *default\_lib\_dir=* in *dosemu.users* the systemwide */var/lib/dosemu* directory may be moved elsewere. For more information see *./doc/README.txt* - */etc/dosemu/dos.ini* IPX configuration file. - *doc/DPR* Dosemu development team: Who is doing which part of the **DOSEMU** project? - *doc/DANG* To help you hack **DOSEMU** code. - *doc/README.\** Various documentation. - *QuickStart* To set up **DOSEMU** quickly. - *ChangeLog* Changes in **DOSEMU** since the last release. - *MSDOS mailing list* For more information, mail to - linux-msdos@vger.rutgers.edu ## SEE ALSO [**mkfatimage16**(1)](/mkfatimage16/1.md), [**mtools**(1)](/mtools/1.md)