
The dosemu HOWTO

Mike Deisher. Updated by Uwe Bonnes for dosemu-0.64.4, 15 March 1997.
Updated by David Hodges, davidhodges@altavista.iname.com

   For dosemu-1.2, 27 September 2003

   This is the `Frequently Asked Questions' (FAQ) / HOWTO document for
   dosemu. The most up-to-date version of the dosemu-HOWTO may be found
   at http://www.dosemu.org.
     _________________________________________________________________

   Table of Contents
   1. The preliminaries

        1.1. What is dosemu, anyway?
        1.2. What operating systems does dosemu work under?
        1.3. What processors does dosemu work on?
        1.4. What if I have an Alpha/Sparc/Motorola/other non-Intel CPU?
        1.5. Do I need MS-DOS to use dosemu?
        1.6. Can I run Microsoft Windows programs under dosemu?
        1.7. I want to run something that won't run under DOSemu or Wine
        1.8. Names and numbers
        1.9. What version of Dosemu should I use?
        1.10. What's the newest version of dosemu and where can I get it?
        1.11. Where can I ask questions?
        1.12. Where can I report bugs and ask questions?
        1.13. What documentation is available for dosemu?
        1.14. I have a program that fails, not listed in EMUfailure.txt
        1.15. How do I submit changes or additions to the HOWTO?
        1.16. Message from Greg...

   2. Compiling and installing dosemu

        2.1. Where are the installation instructions?
        2.2. Top problems while compiling and installing dosemu.
        2.3. How do I make a.out binaries?
        2.4. How do I compile dosemu on a machine with low memory?
        2.5. Compilation fails with some strange error regarding "slang"
        2.6. What configurable options are available?
        2.7. Do I need to run dosemu as root?
        2.8. How do I patch dosemu?
        2.9. What versions of DOS are known to run with dosemu?

   3. Hard disk setup

        3.1. How do I use my hard disk with dosemu?
        3.2. How can I access the hdimage from Linux?
        3.3. Can I use my stacked/double-spaced/super-stored disk?
        3.4. Creating your own hdimage file.

   4. Parallel ports, serial ports and mice

        4.1. Port access worked with older version, but doesn't work now!
        4.2. Port access was faster with older versions!
        4.3. Where are the (microsoft compatible) mouse drivers?
        4.4. Why doesn't the mouse driver work?
        4.5. Why does dosemu clobber COM4?
        4.6. How do I use dosemu over the serial ports?
        4.7. How can I switch between dosemu and a shell over the serial
                line?

        4.8. How can I get the parallel ports to work?

   5. Multiple users and Non-interactive sessions

        5.1. Can I use dosemu on a multi-user system?
        5.2. How can I run dos commands non-interactively?

   6. dosemu and Netware

        6.1. How do I get Netware access from dosemu?

   7. dosemu and X-windows(97/2/9).

        7.1. How do I obtain fullscreen mode in xdosemu?
        7.2. Can I run dosemu in console mode while running X?
        7.3. Is it possible to run dosemu in a window in X-windows?
        7.4. Xdosemu does not work on a remote X-display!
        7.5. Xdosemu does not find the VGA font
        7.6. The vga font is very small on my high resolution display
        7.7. Dosemu compilation fails with some strange error regarding
                X!

        7.8. Does ansi emulation work properly?

   8. dosemu and MS-Windows 3.x

        8.1. Is it possible to run MS-Windows 3.x under dosemu?
        8.2. Can I run 32bit stuff in Windows?
        8.3. Can I run Windows 3.x in xdosemu
        8.4. Can I install windows from within dosemu?
        8.5. Notes for the mouse under win3.x-in-xdosemu:

   9. Video and sound

        9.1. Can I run 32-bit video games under dosemu?
        9.2. Exiting from dosemu on the console gives me a screen full of
                garbage.

        9.3. Why doesn't my soundcard software work with dosemu?

   10. Problems and fixes

        10.1. Security issues
        10.2. dosemu says "ERROR: general protection" and terminates when
                I run some program

        10.3. Dosemu dies when booting. I have Win95 installed.
        10.4. Dosemu hangs! How can I kill it?
        10.5. Dosemu crashed and now I can't type anything.
        10.6. I've enabled EMS memory in dosemu.conf but it does not
                help.

        10.7. How do I get rid of all those annoying "disk change"
                messages?

        10.8. Why won't dosemu run a second time after exiting in console
                mode?

        10.9. Why will dosemu run in a term but not in the console?
        10.10. How can I speed up dosemu?
        10.11. How do I see debugging output?
        10.12. Why are my keystrokes echoed ttwwiiccee??
        10.13. Dosemu scrambles my screen?
        10.14. MS FoxPro 2.6 won't run

   11. Contributing to the dosemu project

        11.1. Who is responsible for dosemu?
        11.2. I want to help. Who should I contact?

1. The preliminaries

1.1. What is dosemu, anyway?

   To quote the manual, "dosemu" is a user-level program which uses
   certain special features of the Linux kernel and the 80386 processor
   to run MS-DOS/FreeDOS/DR-DOS in what we in the biz call a `DOS box.'
   The DOS box, a combination of hardware and software trickery, has
   these capabilities:

     * the ability to virtualize all input/output and processor control
       instructions
     * the ability to support the word size and addressing modes of the
       iAPX86 processor family's "real mode," while still running within
       the full protected mode environment
     * the ability to trap all DOS and BIOS system calls and emulate such
       calls as are necessary for proper operation and good performance
     * the ability to simulate a hardware environment over which DOS
       programs are accustomed to having control.
     * the ability to provide DOS services through native Linux services;
       for example, dosemu can provide a virtual hard disk drive which is
       actually a Linux directory hierarchy.
     _________________________________________________________________

1.2. What operating systems does dosemu work under?

   Dosemu is primarily written for Linux. At one time it also worked on
   NetBSD and possibly FreeBSD, however the graphics emulation was
   unlikely to work on NetBSD, which means that all DOS programs that use
   graphics mode (most DOS programs) did not work under NetBSD.
     _________________________________________________________________

1.3. What processors does dosemu work on?

   Dosemu only works on Intel 80x86 processors, e.g. 80386, 80486,
   Pentium etc.
     _________________________________________________________________

1.4. What if I have an Alpha/Sparc/Motorola/other non-Intel CPU?

   Dosemu only works on Intel 80x86 processors but there are
   alternatives: Bochs (http://bochs.sourceforge.net) is an open source
   PC emulator that runs on most Unixes (as well as MS-Windows). DOSBox
   (http://dosbox.sourceforge.net) also emulates the CPU but specializes
   in DOS games. QEMU
   (http://fabrice.bellard.free.fr/qemu/index.org.html) can launch Linux
   processes compiled for one CPU on another CPU. Wine and DOSEMU are the
   main targets for QEMU. There are other (non-free) alternatives - see
   the comp.emulators.misc FAQ, available via usenet or
   http://www.faqs.org/faqs/emulators-faq/
     _________________________________________________________________

1.5. Do I need MS-DOS to use dosemu?

   No. You need some version of DOS but not necessarily MS-DOS. The
   supplied FreeDOS will do for almost all DOS programs. One notable
   exception is Windows 3.x. See also Section 2.9.
     _________________________________________________________________

1.6. Can I run Microsoft Windows programs under dosemu?

   Yes, but it would be better to use the Windows emulator Wine
   (http://www.winehq.com). If you insist on running Windows under
   dosemu, see section 8 - dosemu and MS-Windows 3.1.
     _________________________________________________________________

1.7. I want to run something that won't run under DOSemu or Wine

   See Section 1.4, or try VMWARE at http://www.vmware.com or Plex86 at
   http://www.plex86.org
     _________________________________________________________________

1.8. Names and numbers

   (xx/yy/zz)
          means day zz in month yy in year xx.

   winemu
          winemu mean WinOS/2 running in dosemu.
     _________________________________________________________________

1.9. What version of Dosemu should I use?

   Dosemu uses the same numbering scheme as the kernel used. Uneven
   second numbers are for possible unstable developer releases, even
   second numbers are for releases considered stable. At the time of
   writing, 1.4.0 is the latest stable release, while 1.3.5 is the latest
   developer's release. So if you just want to use dosemu, get the latest
   stable release.
     _________________________________________________________________

1.10. What's the newest version of dosemu and where can I get it?

   The newest stable version of dosemu as of 2007/05/05 is dosemu-1.4.0
   and can be obtained at http://www.dosemu.org/.

   We just decided to leave BETA stage, however: there may be serious
   bugs and very little documentation for new features. The development
   version is particularly likely to have bugs. Please use it only if you
   like to do active development. Preferably fix bugs in the development
   version instead of reporting them.
     _________________________________________________________________

1.11. Where can I ask questions?

   If you have problems regarding installing and running dosemu after
   reading the documentation, first try to help yourself: Your question
   has probably been asked and perhaps answered before. Try some search
   engine on the internet to retrieve that information. E.g. you can ask
   http://groups.google.com to find all newsnet articles containing the
   keywords of your question. Helping yourself will probably be faster
   than asking a well known question. It also frees up the time of
   developers from answering trivial questions and so helps the further
   development of dosemu.
     _________________________________________________________________

1.12. Where can I report bugs and ask questions?

   If you want to ask questions and report bugs regarding dosemu, you
   should consider subscribing to the linux-msdos mailing list. To
   subscribe, send mail to Majordomo@vger.kernel.org with the following
   command in the body of your email message:
       subscribe linux-msdos your_username@your.email.address

   If you ever want to remove yourself from the mailing list, you can
   send mail to Majordomo@vger.kernel.org with the following command in
   the body of your email message:
       unsubscribe linux-msdos your_username@your.email.address

   (95/8/11). When you are subscribed to linux-msdos, you can send your
   report as mail to linux-msdos@vger.kernel.org. There is a gate that
   send mails to linux-msdos@vger.kernel.org as postings to the newsgroup
   named linux.dev.msdos. If your News provider doesn't carry that group,
   ask her(him) to add that group. Before you ask a question, you should
   carefully read all of the documentation, including this HOWTO and
   check one of the mailing list archives listed at
   http://www.dosemu.org/mailinglist.html to see whether your question
   has already been asked and answered.

   Alternatively, use the SourceForge Bug Tracking System for DOSEMU at
   http://sourceforge.net/tracker/?atid=457447&group_id=49784&func=browse
   . The advantage of this system is that your bug is less likely
   forgotten.
     _________________________________________________________________

1.13. What documentation is available for dosemu?

   Dosemu comes with documentation. The main documentation files
   README.txt and README-tech.txt cover virtually all aspects of dosemu
   and may be more up-to-date than this HOWTO.

   The "dosemu Novice's Altering Guide" or DANG is a road map to the
   inner workings of dosemu. It is designed for the adventurous, those
   who wish to modify the source code themselves. The DANG is maintained
   by Alistair MacDonald (alistair@slitesys.demon.co.uk) and is found in
   the doc directory of the dosemu source tree.

   The EMU failure list (EMUfailure.txt) is a partial list of programs
   known not to work under dosemu.

   And then, of course, there is the dosemu FAQ/HOWTO. But you already
   know about that, don't you. It is also posted once in a while to the
   mailing list and found in the doc-directory. The most recent version
   can be found at http://www.dosemu.org.
     _________________________________________________________________

1.14. I have a program that fails, not listed in EMUfailure.txt

   First check, if the failure of your program is not caused by some of
   the fundamental incapabilities of dosemu, listed in EMUfailure.txt. If
   you think you have something new, please report to
   linux-msdos@vger.kernel.org. Perhaps it can be made going with the
   help others. Give detailed information about your setup, tell the
   version of kernel, dosemu etc and name the observed errors. You can
   use xdosemu to cut and paste the error message into your report. But
   keep your report in a readable form. We know the content of the
   commented out options. So only send the active lines from your
   dosemu.conf and ~/.dosemurc. Try running dosemu with some or all debug
   output turned on and scan through your debug output and at first only
   send those parts you think are relevant. Few people are willing to
   decode some long attachment to a mail, to do debugging for others. But
   keep your logs at hand, in case others ask detailed questions.
     _________________________________________________________________

1.15. How do I submit changes or additions to the HOWTO?

   The preferred method is to edit the file dosemu-HOWTO-xx.x.sgml to
   incorporate the changes, create a diff file by typing something like:
       diff -uw original-file new-file

   and send it to linux-msdos@vger.kernel.org. If you do not know SGML,
   that's ok. Changes or new information in any form will be accepted.
   Creating the diff file just makes it easier on the HOWTO maintainer.
   :-)
     _________________________________________________________________

1.16. Message from Greg...

   Unless otherwise stated, Linux HOWTO documents are copyrighted by
   their respective authors. Linux HOWTO documents may be reproduced and
   distributed in whole or in part, in any medium physical or electronic,
   as long as this copyright notice is retained on all copies. Commercial
   redistribution is allowed and encouraged; however, the author would
   like to be notified of any such distributions.

   All translations, derivative works, or aggregate works incorporating
   any Linux HOWTO documents must be covered under this copyright notice.
   That is, you may not produce a derivative work from a HOWTO and impose
   additional restrictions on its distribution. Exceptions to these rules
   may be granted under certain conditions; please contact the Linux
   HOWTO coordinator at the address given below.

   In short, we wish to promote dissemination of this information through
   as many channels as possible. However, we do wish to retain copyright
   on the HOWTO documents, and would like to be notified of any plans to
   redistribute the HOWTOs.

   If you have questions, please contact Greg Hankins, the Linux HOWTO
   coordinator, at gregh@cc.gatech.edu(95/8/11).
     _________________________________________________________________

2. Compiling and installing dosemu

2.1. Where are the installation instructions?

   The installation instructions are in the file INSTALL, included in the
   distribution.
     _________________________________________________________________

2.2. Top problems while compiling and installing dosemu.

    1. Forgetting to read the README and INSTALL.
    2. Try to compile some old version of dosemu.
    3. Use dosemu with a kernel that does not have IPC compiled in.
    4. Compile with gcc older than 2.95.2, egcs older than 2.91.66
       (1.1.2) or glibc older than 2.1.3.
    5. Forgetting to use a dosemu-freedos-bin tarball when no other DOS
       is available on the system.
    6. Run DOSEMU with partition access while they are already mounted.
     _________________________________________________________________

2.3. How do I make a.out binaries?

   Starting with version 0.64.4 there is no a.out support any more. If
   you absolutely need it, you must use version 0.64.3.1. The configure
   script then should take care for this, if your setup is a standard
   setup.
     _________________________________________________________________

2.4. How do I compile dosemu on a machine with low memory?

   Marty Leisner <leisner@sdsp.mc.xerox.com> reported (95/4/8) that:

   If you have problems with running out of swap space you may want to
   add CFLAGS+=-fno-inline after CFLAGS is defined in
   src/dosext/dpmi/Makefile. Be careful before you do this and check for
   the existence of swap space. I found Linux crashes at times when it
   has no swap space.
     _________________________________________________________________

2.5. Compilation fails with some strange error regarding "slang"

   You probably have plugin_slang off in your compiletime-settings file.
   You need to change it to plugin_slang on and recompile.
     _________________________________________________________________

2.6. What configurable options are available?

   The compiletime-settings.help file describes the options you can
   change at compile time. README.txt describes the options you can
   change at run time.
     _________________________________________________________________

2.7. Do I need to run dosemu as root?

   No. Although most of dosemu drops root privilege after initialization,
   it is still safer to not run dosemu as root. Most normal DOS
   applications don't need dosemu to run as root, especially if you run
   dosemu under X. Thus you should not allow users to run a suid root
   copy of dosemu, wherever possible, but only a non-suid copy. You can
   configure this on a per-user basis using the dosemu.users file, or
   setup a configuration using sudo and use dosemu -s (see INSTALL).

   Programs that require direct access to hardware ports (e.g. if the
   program needs to talk to some unusual hardware that is not supported
   by Linux and dosemu) require dosemu to run as root but printers,
   serial ports, mice, video cards and sound are emulated by dosemu so
   you won't usually need direct hardware access and won't need to run as
   root to use these. Some programs are just too sneaky for dosemu's
   hardware emulation to work properly though ...

   You will need to edit dosemu.users (see dosemu.users.example) for any
   suid-root/sudo access beyond console graphics or run dosemu as root
   for hardware access.
     _________________________________________________________________

2.8. How do I patch dosemu?

   If you do patch dosemu from one version to another, do "make
   pristine;./configure; make". If you don't make pristine, at least the
   version of the new executable will be wrong, if the whole thing
   compiles at all (97/2/9).
     _________________________________________________________________

2.9. What versions of DOS are known to run with dosemu?

   All versions of DOS should work with dosemu, with the following
   caveats:

   DOS 4.01 had problems by itself, so it won't work reliably with dosemu
   either.

   With MsDos-7 aka Win95 you must not start the graphic shell at bootup.
   If you make the hdimage bootable with the so called "Rescue Disk" you
   are offered to make during the Windows installation, you get the right
   settings. If you use your normal Win95 installation to transfer the
   system files, have a look at the msdos.sys written on the hdimage and
   change the settings under the section [Options] to have entries like:
    [Options]
    Logo=0
    BootGUI=0
     _________________________________________________________________

3. Hard disk setup

3.1. How do I use my hard disk with dosemu?

   First, mount your dos hard disk partition as a Linux subdirectory. For
   example, you could create a directory in Linux such as /dos (mkdir -m
   755 /dos) and add a line like:
       /dev/hda1       /dos     msdos   umask=022

   to your /etc/fstab. (In this example, the partition is mounted
   read-only. You may want to mount it read/write by replacing "022" with
   "000" and using the -m 777 option with mkdir). Now mount /dos.

   Now you can run (for instance) lredir f: linux\fs/dos at the DOS
   prompt to map drive F to /dos. Re-redirecting C using lredir c:
   linux\fs/dos works too but then you need to copy all your dosemu
   utilities (in c:\dosemu) to a place where they can still be found. If
   you want to boot via /dos, read on.

   The README.txt says:

   you just can have a Linux directory containing all what you want to
   have under your DOS C:. Copy your IO.SYS, MSDOS.SYS or what ever to
   that directory (e.g. $HOME/.dosemu/bootdir), put $_hdimage = "bootdir"
   into your $HOME/.dosemurc, and up it goes. Alternatively you can
   specify an absolute path such as "/dos" or
   "/home/username/dosemu/freedos". DOSEMU makes a lredir'ed drive out of
   it and can boot from it. You can edit config.sys and autoexec.bat
   within this directory before you start dosemu. Further more, you may
   have a more sohisticated setup. Given you want to run the same DOS
   drive as you normal have when booting into native DOS, then you just
   mount you DOS partition under Linux (say to /dos) and put links to its
   subdirectories into the boot dir. This way you can decide which
   files/directories have to be visible under DOSEMU and which have to be
   different. Here's a small and incomplete example bootdir setup:
    config.sys
    autoexec.bat
    command.com -> /dos/command.com
    io.sys -> /dos/io.sys
    msdos.sys -> /dos/msdos.sys
    dos -> /dos/dos
    bc -> /dos/bc
    windows -> /dos/windows
     _________________________________________________________________

3.2. How can I access the hdimage from Linux?

   Use mtools. With a line in /etc/mtools.conf like:
    drive n:  file="/path/to/hdimage" MTOOLS_SKIP_CHECK=1 \
    MTOOLS_LOWER_CASE=1 MTOOLS_NO_VFAT=1 partition=1 offset=128

   you can use the mtools on the hdimage, like "mdir n:". "mcopy
   n:/config.emu /tmp" copies the config.emu file from the hdimage to
   /tmp/config.emu. You can edit it there and copy it back. Use a drive
   letter you find sensible. "N:" is only an example.
     _________________________________________________________________

3.3. Can I use my stacked/double-spaced/super-stored disk?

   At this time, compressed drives cannot be accessed via the redirector
   (lredir or emufs) on a standard kernel. There is a patch for the
   kernel to mount compressed files under the name "dmsdosfs". Find it on
   ibiblio.org and its mirrors
   http://ibiblio.org:/pub/Linux/system/filesystems/dosfs/. A good idea
   is also to look in http://ibiblio.org:/pub/Linux/Incoming for a newer
   version. The "wholedisk" option in older versions of dosemu is no
   longer allowed in recent versions, however, a line like
       $_hdimage = "/dev/hda1"

   may work, if you have read and write access to this device and at the
   risk that you could lose all data in that partition on a dosemu crash.
   Also it is extremely dangerous to let two dosemu sessions access the
   partition at the same time.

   If your dos partition is already mounted with write access and you try
   to run dosemu with partition access, dosemu will print a warning
   message and abort. This prevents DOS and Linux from making independent
   writes to your disk and trashing the data on your dos partition
   (95/8/11).

   Holger Schemel <q99492@pbhrzx.uni-paderborn.de> reported (94/2/10)
   that:

   Works even fine under dosemu with MS-DOS 6.0. If you have problems,
   then you have to edit the file `DBLSPACE.INI' manually and change the
   disk letter to the letter your drive gets under dosemu.
     _________________________________________________________________

3.4. Creating your own hdimage file.

   There is an extra util program called mkfatimage16 which allows for
   creating a hdimage file headers. The full information is in the
   manpage (man/mkfatimage16.1) included in your distribution.

   To create a hard disk image file with a geometry corresponding to that
   of a real hard disk of 32 megabytes run:
       mkfatimage16 -k 32768 > hdimage

   This is probably too large for most needs; if you need this much
   space, consider using the disk redirector.

   Usually it is a good idea to format the drive after it.
     _________________________________________________________________

4. Parallel ports, serial ports and mice

4.1. Port access worked with older version, but doesn't work now!

   Read README.txt and the port-section in dosemu.conf. Also, you must
   now you the -s dosemu command line switch.
     _________________________________________________________________

4.2. Port access was faster with older versions!

   To have a chance to log port access, by default every port access
   produces an exception out of vm86-mode. This takes some time. If you
   don't want to log port access, use the keyword fast in the appropriate
   port statement.
     _________________________________________________________________

4.3. Where are the (microsoft compatible) mouse drivers?

   Tom Kimball <tk@pssparc2.oc.com> reported (93/11/24) that:

   Several people said to use a different mouse driver and suggested
   some. I found a couple that seem to work fine.
    oak.oakland.edu:/pub/msdos/mouse/mouse701.zip   (mscmouse)
    oak.oakland.edu:/pub/msdos/mouse/gmous102.zip   (gmouse)

   Normally you can use dosemu's internaldriver, so you don't need any
   additional mousedriver in dosemu outside winemu (97/2/10).
     _________________________________________________________________

4.4. Why doesn't the mouse driver work?

   Mark Rejhon <mdrejhon@magi.com> reported (95/4/7) that:

   If you start the mouse driver and it just hangs (it might actually
   take 30-60s), but if you are waiting longer than a minute for the
   mouse driver to start, try specifying the COM port that the mouse is
   on, at the mouse driver command line.
     _________________________________________________________________

4.5. Why does dosemu clobber COM4?

   Rob Janssen <rob@pe1chl.ampr.org> reported (94/3/24) that:

   According to <jmorriso@bogomips.ee.ubc.ca>, "dosemu still clobbers
   COM4 (0x2e8, IRQ 5). 0x2e8 isn't in ports{} in config. I have to run
   setserial /dev/ttyS3 irq 5 on it after dosemu exits."

   This is caused by your VGA BIOS. I have found that by enabling the IO
   port trace and seeing where it was clobbered.

   Disable some ports in config and it will work fine. When you then have
   problems with the video, try to enable more selective ranges of IO
   addresses (e.g., 40-43).
     _________________________________________________________________

4.6. How do I use dosemu over the serial ports?
     _________________________________________________________________

4.7. How can I switch between dosemu and a shell over the serial line?

   John Taylor <taylor@pollux.cs.uga.edu> reported (94/5/25) that:

   I am running Linux 1.1.13 and want to point out a great feature that
   should be protected and not taken out (IMHO). With the 52 version, I
   can run the program, "screen." From screen, i can invoke dosemu -D-a.
   What is really great (IMHO) is the screen commands (the CTRL-A cmds)
   still work. This means I can do a CTRL-A C and add another unix shell,
   and switch between the two (DOS / UNIX). This allows me to use dosemu
   over the serial line really well, because switching is made easy.

   You may also consider using dosemu -dumb. In this case the escape
   sequences from the DOS applications go directly to the terminal.
     _________________________________________________________________

4.8. How can I get the parallel ports to work?

   The dosemu.conf has lines at the end to redirect printers to either
   lpr or a file. If you want direct access to the bare metal, comment
   out these emulation lines, and add the line:
       $_ports = "device /dev/lp0 fast range 0x3bc 0x3bf" # lpt0

   for the "monitor card" printer port (corresponds to /dev/lp0), or:
       $_ports = "device /dev/lp1 fast range 0x378 0x37f" # lpt1

   or:
       $_ports = "device /dev/lp1 fast range 0x278 0x27f" # lpt2

   for LPT1 (/dev/lp1) or LPT2 (/dev/lp2) respectively(97/2/9).

   Hans Lermen <lermen@dosemu.org> writes:

   But NOTE: these lines should not be _added_ simply, the string should
   be concatenated such as:
    $_ports = "...."
    $_ports = $_ports, " device /dev/lp0 fast range 0x3bc 0x3bf"
    =
    This blank is important

   Note: newer kernels don't have hardcoded dependencies between /dev/lp*
   and ioports. Check /proc/ioports for lines such as 0378-037a :
   parport0.
     _________________________________________________________________

5. Multiple users and Non-interactive sessions

5.1. Can I use dosemu on a multi-user system?

   Yes, you can configure dosemu on a per-user basis. See README.txt for
   details.
     _________________________________________________________________

5.2. How can I run dos commands non-interactively?

   You can do any of the following:

    1. use the keystroke configuration option and the -input command line
       option as described in the manual page to specify keystrokes on
       the command line that will act exactly as if you had typed them
       within dosemu.
    2. Use the dosemu [-E] dos-command and unix -e as your last line in
       autoexec.bat. The specified dos command is executed. If '-E' is
       not given, then DOSEMU exits after running the command.

   Here are some additional alternatives:

   Daniel T. Schwager <danny@dragon.s.bawue.de> reported (94/7/2) that:

   You can use different dosemu.conf files (and different hd-boot-images
   with different autoexec.bat's) and call dosemu like:
       $ dosemu -f my_quicken_q_exe_dosemu.conf

   ---------------------

   Dietmar Braun <braun@math20.mathematik.uni-bielefeld.de> reported
   (94/7/4) that:

   This is no problem at all when you use the redirector of dosemu. It is
   possible to redirect a drive letter to a linux path given by an
   environment variable.

   So I have a shell script named "DOS" which does something like:
    mkdir /tmp/dos.$$
    DOSTMP=/tmp/dos.$$; export DOSTMP

   and then a little trick to get "echo $* > $DOSTMP/startup.bat" really
   working (actually a small C Program which turns `/' in `\' and
   terminates lines correctly for messy dos with cr/lf pairs and adds ^Z
   at the end of the file), creates startup files, links and so on in
   this directory, and then starts dosemu. Within "autoexec.bat" drive c:
   is redirected from hdimage to this tmp-directory, which has links for
   $HOME and $PWD.

   So if I want to see my filenames shortened to 8.3 I can type "DOS dir"
   and I get my current directory listing. So I have full DOS multi user
   (I don't have any DOS partition and redirecting to Linux preserves
   user permissions) and multi tasking. (dosemu sessions are completely
   independent). I did this once to be able to use a dos driver for my
   printer. My printcap df is actually a DOS program. So you can even
   make DOS executables act as lpr filters.
     _________________________________________________________________

6. dosemu and Netware

6.1. How do I get Netware access from dosemu?

   As always, access through the Linux filesystem is preferred. Mount
   your Netware drives with Caldera's Netware utilities or Volker
   Lendecke's free ncpfs utility ftp://ftp.gwdg.de:/pub/linux/misc/ncpfs.
   If you need real IPX access, e.g. to run Novell's "syscon", read
   doc/NOVELL-HOWTO.txt. You probably can not currently access Netware
   from FreeDOS.
     _________________________________________________________________

7. dosemu and X-windows(97/2/9).

7.1. How do I obtain fullscreen mode in xdosemu?

   Toggle between windowed and fullscreen mode using Ctrl-Alt-F.
     _________________________________________________________________

7.2. Can I run dosemu in console mode while running X?

   Ronald Schalk <R.Schalk@uci.kun.nl> reported (94/1/17) that:

   Yes, no problem. Just remember to use ctrl-alt-<Fn> to go to a Virtual
   Console (VC), and you can run any Linux application (dosemu is a
   linux-application). I've got almost always WP5.1 in a dos session.

   [Note: Use ctrl-alt-F7 to switch back to X from dosemu, if X runs on
   VC7.]
     _________________________________________________________________

7.3. Is it possible to run dosemu in a window in X-windows?

   If you have X installed and you have successfully compiled dosemu and
   run it successfully outside X-windows, you should be able to run
   xdosemu or dosemu -X right away to bring up a dosemu window. If this
   does not work, make sure:

    1. Dosemu has X support compiled in. This is default, however if you
       you have compiled dosemu with "x off" in the compiletime-settings
       file you don't have X support. So changing "x off" to "x on" in
       the compiletime-settings file, followed by "make pristine; make;
       make install" should build you a dosemu-executable with X support,
       if you have the X-libraries installed in /usr/X11R6.
    2. You might need to fix backspace and delete; but nowadays this is
       rarely necessary. In that case, set up your X key-mappings. In an
       xterm, type xmodmap -e "keycode 22 = 0xff08", and then xmodmap -e
       "keycode 107 = 0xffff".
    3. Configure the X-related configuration options in ~/.dosemurc.

   Alternatively, you can run dosemu inside a color xterm, which is not
   recommended because many color xterms have buggy support for the
   complex text display capabilities of dosemu. This does not require
   X_SUPPORT to be compiled into dosemu. However, if you really want to
   do this, do the following steps:

    1. If necessary set up your X key-mappings as explained above.
    2. Configure the terminal-related (not X-related) settings in
       ~/.dosemurc.

   Marty Leisner <leisner@sdsp.mc.xerox.com> reported (95/3/31) that:

   I have xrdb log the following resources
    dosxterm*Font:  vga
    dosxterm*geometry:      80x25
    dosxterm*saveLines: 25

   or I alias dosxterm to term -fn vga -title dosxterm -geometry 80x25
   -sl 25.

   If you use the xrdb method, all you have to do is run xterm -name
   dosxterm.
     _________________________________________________________________

7.4. Xdosemu does not work on a remote X-display!

   At present, dosemu is set up to use the MIT shared memory extensions.
   This extension only works on a local display. If you want to run
   xdosemu on a remote display, you might need to set $_X_mitshm=(off) in
   your dosemu.conf or .dosemurc.
     _________________________________________________________________

7.5. Xdosemu does not find the VGA font

   Check that the vga fonts you installed are listed in the font.dir of
   the directory you installed the fonts in:
    hertz:~> grep misc /usr/X11R6/lib/X11/XF86Config
    FontPath    "/usr/X11R6/lib/X11/fonts/misc/"
    hertz:~> grep vga /usr/X11R6/lib/X11/fonts/misc/fonts.dir
    vga.pcf vga
    vga11x19.pcf vga11x19
    hertz:~> ls /usr/X11R6/lib/X11/fonts/misc/vga*
    /usr/X11R6/lib/X11/fonts/misc/vga.pcf
    /usr/X11R6/lib/X11/fonts/misc/vga11x19.bdf
    /usr/X11R6/lib/X11/fonts/misc/vga11x19.pcf

   If you installed some X-fonts, like you did when you installed dosemu
   with X-Support for the first time, "mkfontdir" and then "xset fp
   rehash" needs to be run. The dosemu install should take care for
   "mkfontdir" and tells you about "xset fp rehash". Tell us if it
   doesn't work for you. (97/2/13)
     _________________________________________________________________

7.6. The vga font is very small on my high resolution display

   Set $_X_font="vga11x19".
     _________________________________________________________________

7.7. Dosemu compilation fails with some strange error regarding X!

   As stated above, dosemu uses the MIT shared memory extensions by
   default. Under XFree86 they are only available with Version 3.1.2 and
   above. If you have an older version, consider to upgrade, or configure
   dosemu to not use this extension by setting mitshm off in
   compiletime-settings (97/2/9).
     _________________________________________________________________

7.8. Does ansi emulation work properly?

   Marty Leisner <leisner@sdsp.mc.xerox.com> reported (95/3/31) that:

   Yes. I use nnansi.com under X windows. I find 25, 43 and 50 line mode
   work properly, however 50 line mode is difficult to use on a 1024x768
   screen (unless smaller fonts are used or you use a bigger screen. 43
   line mode will resize the xterm window to use 43 lines.

   DEVICE=c:\bin\nansi.sys in FreeDOS' config.sys works too, except in
   "dumb" mode.
     _________________________________________________________________

8. dosemu and MS-Windows 3.x

8.1. Is it possible to run MS-Windows 3.x under dosemu?

   Yes, versions up to and including Windows for Workgroups 3.11 are
   currently working, but only under DOSEMU+MSDOS (not FreeDOS).
     _________________________________________________________________

8.2. Can I run 32bit stuff in Windows?

   Sorry, no you can't. Win32s is not supported yet, Win9x is neither.
     _________________________________________________________________

8.3. Can I run Windows 3.x in xdosemu

   Yes, this is similar to using it in DOSEMU on the console; the only
   extra thing to consider here is that the emulated graphics card in
   xdosemu is a Trident, which is most likely different from your real
   graphics card. The mouse also needs some special attention.

   Hints:

    1. For faster graphics (256 colors instead of 16 is faster in
       xdosemu), get the Trident SVGA drivers for Windows. The files are
       tvgaw31a.zip and/or tvgaw31b.zip. They are available at
       garbo.uwasa.fi in /windows/drivers (any mirrors?).
    2. Unpack the Trident drivers.
    3. In Windows setup, install the Trident "800x600 256 color for 512K
       boards" driver.
    4. Start xdosemu.
    5. In Dosemu, start windows.
     _________________________________________________________________

8.4. Can I install windows from within dosemu?

   Yes, up to and including Windows For Workgroups 3.11.
     _________________________________________________________________

8.5. Notes for the mouse under win3.x-in-xdosemu:

    1. In order to let the mouse properly work you need the following in
       your win.ini file:

    [windows]
    MouseThreshold1=0
    MouseThreshold2=0
    MouseSpeed=0

    2. The mouse cursor gets not painted by X, but by windows itself, so
       it depends on the refresh rate how often it gets updated, though
       the mouse coordinates movement itself will not get delayed. In
       fact you have 2 cursors, but the X-cursor is given an `invisible'
       cursor shape while within the DOS-Box.
    3. Because the coordinates passed to windows are interpreted
       relatively, we need to calibrate the cursor. This is done
       automatically whenever you enter the DOS-Box window: The cursor
       gets forced to 0,0 and then back to its right coordinates. Hence,
       if you want to re-calibrate the cursor, just move the cursor
       outside and then inside the DOS-Box again. (97/2/10)
     _________________________________________________________________

9. Video and sound

9.1. Can I run 32-bit video games under dosemu?

   Mark Rejhon <mdrejhon@magi.com> reported (95/4/8) that:

   You can run many 32-bit video games in dosemu. If the game is
   compatible in an OS/2 DOS box, there are chances that it will work in
   dosemu. (Example 32-bit games include Descent, Dark Forces, Mortal
   Kombat 2, Rise of The Triad, which have all successfully been tested
   in recent dosemu releases).

   Before you attempt to run a video game on the console, you must have
   the keyboard configured in raw keyboard mode, and enabled VGA graphics
   modes, in dosemu.conf or run dosemu -s. Moreover you must run DOSEMU
   as root, execute it via sudo or make dosemu.bin suid root.

   Alternatively try running the game in xdosemu; press Ctrl-Alt-F to
   toggle fullscreen mode. Root permissions are unneeded and in almost
   all cases no configuration is necessary, but the speed may be slower
   than on the console, and a few games still exhibit glitches. Use speed
   0 or some high value instead of 0 at the DOS prompt to temporarily set
   your HogThreshold to run DOSEMU at full tilt. After exiting the game
   use speed 1 or exit DOSEMU to give the CPU some rest.

   Note that game timers can be a little bit slow, due to Linux
   multitasking and lack of high-frequency timer support. So the games
   may run from anywhere from 5 to 100 percent speed. Typically, the
   speed is approximately 50 percent in recent dosemu releases and is
   expected to improve eventually.

   Who knows, it might even work. If you can't get it to work, check
   EMUfailure.txt if the program is listed there, or falls in a category
   of programs that at present don't or probably never work with dosemu.
   If you think, it should be listed in EMUfailure.txt, report to
   <linux-msdos@vger.kernel.org>.
     _________________________________________________________________

9.2. Exiting from dosemu on the console gives me a screen full of garbage.

   (95/4/8) The problem is that the font information for the VGA text
   screen is not being saved. Get a copy of the svgalib package. The
   current source is in:
       ibiblio.org:/pub/Linux/libs/graphics/svgalib-1.4.3.tar.gz

   It may also be available as a pre-compiled package in your favorite
   Linux distribution (e.g., Slackware, etc.). Use savetextmode to save
   the current text mode and font to a file in /tmp before running
   dosemu. Then run textmode upon exiting dosemu to restore it.

   Addition from <lermen@elserv.ffm.fgan.de> (97/2/11):

   Have a look also at README-tech.txt, where it is explained how
   dosdebug can aid you recovering.

   If you use a graphical framebuffer console (but not vesafb) then
   /usr/sbin/fbset "1400x1050-60" or whatever your normal resolution and
   frequency are may help.
     _________________________________________________________________

9.3. Why doesn't my soundcard software work with dosemu?

   Dosemu includes a Sound Blaster 16 emulator called SBemu. See
   sound-usage.txt for information on setting this up. It may not work
   for everything. Programs that are known to work are Impulse Tracker
   and most games. One that is known not to work well is FastTracker II.

   If you have trouble getting sound to work at all, make sure you have a
   working OSS driver and have configured everything properly as
   described in sound-usage.txt. If most of your sound software works but
   some programs don't detect sound, make sure your BLASTER environment
   variable is set properly. Finally, make sure you are aware of the
   difference between digital sound, FM, and MIDI; it may be, for
   example, that you have digital sound working but MIDI isn't set up
   properly.

   If you believe DOSEMU really is having trouble with a specific
   program, and it isn't a configuration error on your part, then please,
   submit a bug report! Have a look at sound-usage.txt for information on
   getting debugging output.
     _________________________________________________________________

10. Problems and fixes

10.1. Security issues

   A full featured Dosemu needs to be suid root, e.g to access ports.
   Most dos programs don't need this however so when running under X you
   usually do not need to run dosemu as root. Dosemu runs as suid "root"
   only at the initialization stage, and drops this right thereafter,
   except in a forked "port server" (where necessary). But with DPMI, the
   Dos client program can access the whole user space, hence also can
   modify the dosemu code itself. This cannot lead to privilege elevation
   but may crash DOSEMU. There are several other important security
   considerations discussed in the Security section of README.txt.
     _________________________________________________________________

10.2. dosemu says "ERROR: general protection" and terminates when I run some
program

   This will happen if your program uses DPMI and you do not have DPMI
   enabled. Try changing the line:
       $_dpmi = (off)

   in dosemu.conf to:
       $_dpmi = (nnnn)

   where nnnn is the number of kilobytes of memory you wish to give to
   the DOS program (e.g. Doom requires about 4000 kilobytes).

   Another likely cause is that your program uses VCPI (see
   EMUfailure.txt for more details) or some other means of switching to
   protected mode (other than DPMI), in which case it will never work
   under dosemu.

   If none of these is the case, see Section 1.14.
     _________________________________________________________________

10.3. Dosemu dies when booting. I have Win95 installed.

   Dosemu relies that the Dos-Version on the hdimage and the Drive you
   map to contain command.com are the same. If not, dosemu will crash
   sooner or later. With the dual boot option Win95 offers when pressing
   the F4, F5 and F8 keys with the "Starting Win95" text, versions on the
   Win95 drive may swap. Take special care for command.com. Let your
   shell variable in config.emu point to the correct static version of
   command.com, e.g.: shell=c:\win95\command.com c:\ /P /E:1024
   (97/02/28)
     _________________________________________________________________

10.4. Dosemu hangs! How can I kill it?

   Switch to another console and type dosdebug, then type kill (it may
   take a while but will work eventually).
     _________________________________________________________________

10.5. Dosemu crashed and now I can't type anything.

   Daniel Barlow <jo95004@sable.ox.ac.uk> reported (95/4/8) that:

   If you have no terminal or network access that you can use to log in,
   you may have to press the reset button. If you can still get a usable
   shell somehow, run kbd_mode -a to switch the keyboard out of raw mode,
   and/or stty sane on the console so that you can see what you're
   typing.

   A useful thing to do is to use a script to run dosemu, and run
   kbd_mode -a automatically right after dosemu. When dosemu crashes, the
   script usually will resume running, and execute kbd_mode -a.

   Alternatively, if the magic SysRq key is enabled in the Linux kernel,
   you can use Alt-SysRq-r to switch to xlate mode, and use Alt-Fn to
   switch to any other console (including X, if your screen display is
   thoroughly broken).
     _________________________________________________________________

10.6. I've enabled EMS memory in dosemu.conf but it does not help.

   Rob Janssen <rob@pe1chl.ampr.org> reported (94/7/11): Don't forget to
   load the provided ems.sys from config.sys.
     _________________________________________________________________

10.7. How do I get rid of all those annoying "disk change" messages?

   (94/8/11) Grab and install klogd. Try:
       ibiblio.org:/pub/Linux/system/Daemons/sysklogd1.2.tgz
     _________________________________________________________________

10.8. Why won't dosemu run a second time after exiting in console mode?

   Aldy Hernandez <aldy@sauron.cc.andrews.edu> reported (94/7/8): You
   should disable your video and/or BIOS caching.
     _________________________________________________________________

10.9. Why will dosemu run in a term but not in the console?

   JyiJiin Luo <jjluo@casbah.acns.nwu.edu> reported (94/4/19): I
   experienced exactly the same problem before. I figured out all the
   video shadow in my AMI BIOS must be disabled. Now dosemu runs fine on
   my system.
     _________________________________________________________________

10.10. How can I speed up dosemu?

   In some cases it is useful to play with the value of the HogThreshold
   variable in your dosemu.conf file.

   Daniel Barlow <jo95004@sable.ox.ac.uk> reported (95/4/8): HogThreshold
   should now be set to approximately half of the BogoMips value that the
   system reports on boot.
     _________________________________________________________________

10.11. How do I see debugging output?

   Daniel Barlow <jo95004@sable.ox.ac.uk> reported (95/4/8): As of dosemu
   0.60, debugging output is redirected to a file specified on the
   command line. Use dosemu -D+a -o /tmp/debug to log all debug output to
   /tmp/debug. There should no longer be any need to redirect stderr.
     _________________________________________________________________

10.12. Why are my keystrokes echoed ttwwiiccee??

   Nick Holloway <alfie@dcs.warwick.ac.uk> reported (94/2/22) that:

   After running dos after playing with some stty settings, I was getting
   doubled key presses. I can now reveal what the reason is!

   It only happens when dos is run on the console with `istrip' set. This
   is (I think) because the raw scancodes are mutilated by the `istrip',
   so that key release events look like key press events.

   So, the input processing needs to be turned off when using the scan
   codes on a console (it wouldn't be a good idea to do it for tty
   lines).
     _________________________________________________________________

10.13. Dosemu scrambles my screen?

   For those graphics cards not fully supported in dosemu, with allowed
   console graphics a dosemu crash may leave your console in a scrambles
   and nearly unusable way. To prepare for that situation, Spudgun
   <spudgun@earthlight.co.nz> posted the following solution. First save
   your registers when running on the console ~> cat
   /usr/bin/savetextmode ~> restoretextmode -w /etc/textregs ~>
   restorefont -w /etc/fontdata Then, when a crash happened, run
   following script: restoretextmode -r /etc/textregs restorefont -r
   /etc/fontdata restorepalette

   If it doesn't fix it nothing will! I also found having an X server
   running sometimes put my Vid card's registers into a strange state
   where this script made things worse I think since changing X servers
   and/or running savetextmode on a vt while X was running helped.
   (97/04/08)
     _________________________________________________________________

10.14. MS FoxPro 2.6 won't run

   FoxPro 2.6 doesn't run on network drives. Alexey Naidyonov
   <growler@growler.tsu.tula.ru> states on that problem: And I guess your
   FoxPro files are on lredir'ed disk, yeah? The matter is that FoxPro
   doesn't run on such disk, but when I said $_hdimage="/dev/hda? ..." in
   dosemu.conf, it runs.
     _________________________________________________________________

11. Contributing to the dosemu project

11.1. Who is responsible for dosemu?

   Dosemu is built upon the work of Matthias Lautner and Robert Sanders.
   Bart Oldeman <bart@dosemu.org> is responsible for organizing the
   latest releases of dosemu.
    History of dosemu
    Version    Date                Person
    -------------------------------------------------
    0.1        September 3, 1992   Matthias Lautner
    0.2        September 13, 1992  Matthias Lautner
    0.3        ???                 Matthias Lautner
    0.4        November 26, 1992   Matthias Lautner
    0.47       January 27, 1993    Robert Sanders
    0.47.7     February 5, 1993    Robert Sanders
    0.48       February 16, 1993   Robert Sanders
    0.48pl1    February 18, 1993   Robert Sanders
    0.49       May 20, 1993        Robert Sanders
    0.49pl2    November 18, 1993   James MacLean
    0.49pl3    November 30, 1993   James MacLean
    0.49pl3.3  December 3, 1993    James MacLean
    0.50       March 4, 1994       James MacLean
    0.50pl1    March 18, 1994      James MacLean
    0.52       June 16, 1994       James MacLean
    0.60       April 9, 1995       James MacLean
    0.64.4     February 9,1997     Hans Lermen
    0.66.3     April 20, 1997      Hans Lermen
    0.98.1     December 9, 1998    Hans Lermen
    0.98.6     March 21, 1999      Hans Lermen
    1.0.0      March 6, 2000       Hans Lermen
    1.2.0      January 18, 2004    Bart Oldeman
    1.4.0      May 5, 2007         Bart Oldeman
     _________________________________________________________________

11.2. I want to help. Who should I contact?

   Please join the linux-msdos and dosemu-devel lists; see
   http://www.dosemu.org/mailinglist.html for more information.
