  The dosemu HOWTO
  Rahul Sundaram
  2002-12-27

  Original authoring by Mike Deisher.

  Updated by Uwe Bonnes for dosemu-0.64.4, 15 March 1997

  Updated by David Hodges davidhodges@altavista.net For dosemu-0.98.8,

  rahulsundaram@yahoo.co.in


  ______________________________________________________________________

  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 ten problems while compiling and installing dosemu.
     2.3 How do I make aout 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 Can I run dosemu in console mode while running X?
     7.2 Is it possible to run dosemu in a window in X-windows?
     7.3 Xdos dosen't work on a remote X-display!
     7.4 Xdos dosen't find the VGA font
     7.5 The vga font is very small on my high resolution display
     7.6 Dosemu compilation fails with some strange error regarding X!
     7.7 Does ansi emulation work properly?

  8. dosemu and MS-Windows 3.1

     8.1 Is it possible to run MS-Windows 3.1 under dosemu?
     8.2 Can I run 32bit stuff with winemu
     8.3 Errormessage: Cannot find the vdtapi.386 file when starting dosemu
     8.4 Windows 3.x in xdos:
     8.5 Can I install windows from within dosemu?
     8.6 Notes for the mouse under win31-in-xdos:
     8.7 Why did my Icon disappear from the Program manager?

  9. Video and sound

     9.1 Can I run 32-bit video games under dosemu?
     9.2 Exiting from dosemu gives me a screen full of garbage.
     9.3 Why doesn't my soundcard software work with dosemu?

  10. Games

     10.1 Duke3d dosen't work

  11. Problems and fixes

     11.1 Security issues
     11.2 dosemu says "ERROR: general protection" and terminates when I run some program
     11.3 Dosemu dies when booting. I have Win95 installed.
     11.4 Dosemu hangs! How can I kill it?
     11.5 Dosemu crashed and now I can't type anything.
     11.6 I've enabled EMS memory in dosemu.conf but it does not help.
     11.7 How do I get rid of all those annoying "disk change" messages?
     11.8 Why won't dosemu run a second time after exiting in console mode?
     11.9 Why will dosemu run in a term but not in the console?
     11.10 How can I speed up dosemu?
     11.11 My CDROM drive has problems reading some files under dosemu.
     11.12 How do I see debugging output?
     11.13 Why are my keystrokes echoed ttwwiiccee??
     11.14 Dosemu scrambles my screen?
     11.15 MS FoxPro 2.6 won't run

  12. Contributing to the dosemu project

     12.1 Who is responsible for dosemu?
     12.2 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:

  o the ability to virtualize all input/output and processor control
  instructions

  o 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

  o the ability to trap all DOS and BIOS system calls and emulate such
  calls as are necessary for proper operation and good performance

  o the ability to simulate a hardware environment over which DOS
  programs are accustomed to having control.

  o 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. It also works on NetBSD and
  possibly FreeBSD, however the graphics emulation is unlikely to work
  on NetBSD, which means that all DOS programs that use graphics mode
  (most DOS programs) will 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://www.bochs.com) is an open source shareware
  PC emulator that runs on most Unixes (as well as MS-Windows), and
  there are other (non-free) alternatives - see the comp.emulators.misc
  FAQ, available via usenet or ftp://rtfm.mit.edu/pub/usenet-by-
  hierarchy/comp/emulators/misc/


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

  No. You need some version of DOS but not necessarily MS-DOS.  See the
  section "What versions of DOS are known to run with dosemu ?"


  1.6.  Can I run Microsoft Windows programs under dosemu ?

  Not reliably. You 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.

  1.8.  Names and numbers


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



       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. Uneven second
  numbers are for possible unstable developer releases, even second
  numbers are for releases considered stable. At the time of writing,
  0.98.8 is the latest stable release, while 0.99.10 is the latest
  developer's release. So if you 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 version of dosemu as of 99/04/09 is dosemu0.98.8 and can be
  ftp'ed from:

       ftp://ftp.dosemu.org/pub/dosemu/



  Remember that this is ALPHA code, 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. Don't report bugs in the development
  version, fix them instead.


  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://www.dejanews.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 question 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.rutgers.edu 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.rutgers.edu 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.rutgers.edu. There is a gate that
  send mails to linux-msdos@vger.rutgers.edu as postings to the news­
  group 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.


  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.rutgers.edu.  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 xdos
  to cut and paste the error message into your report. But keep your
  report in a readable form. We know the content of ../etc/config.dist.
  So only send the active lines from your dosemu.conf. 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 davidhodges@altavista.net.  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, "QuickStart", included
  in the distribution.


  2.2.  Top ten problems while compiling and installing dosemu.


  1. Forgetting to read the QuickStart Guide.

  2. Try to compile some old version of dosemu.

  3. Try to compile with a kernel older than 2.0.28 or 2.1.15.

  4. Having the wrong linux kernel source sitting in /usr/src/linux or
  missing /usr/src/linux/include/version.h

  5. Use dosemu with a kernel that does not have IPC compiled in.

  6. Compile with gcc older than 2.7.2 or libc older than 5.x.x.

  7. Forget to edit your /etc/dosemu.conf, /etc/dosemu.users and
  /var/lib/dosemu/global.conf files

  8. Run DOSEMU with partition access while they are already mounted.

  9. Don't install dosemu with sufficient privileges (i.e., root).

  10. Try to run programs that use DPMI without enabling dpmi in
  /etc/dosemu.conf


  2.3.  How do I make aout 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 you 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 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

       slangforce off


  in your compiletime-settings file. You need to change it to

       slangforce on


  and recompile.


  2.6.  What configurable options are available ?

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


  2.7.  Do I need to run dosemu as root?

  No. Although dosemu drops root privilege wherever possible, it is
  still safer to not run dosemu as root, especially if you run DPMI
  programs under dosemu. 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 /etc/dosemu.users file.

  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 and video cards (and to a small extent sound -
  hopefully more soon) are emulated by dosemu so you don't need direct
  hardware access and don't need to run as root to use these.


  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:

  FreeDOS (http://www.freedos.org) does not (yet) have a working
  redirector so you will not be able to access your Linux filesystem or
  Novell networking under FreeDOS. Note also that FreeDOS is unreliable
  beta software and may crash unexpectedly, trash its filesystem, etc.
  etc.


  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.  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. /var/lib/dosemu/bootdir), put

            $_hdimage = "bootdir"


    into your /etc/dosemu.conf, and up it goes. DOSEMU makes a lredir'ed
    drive out of it and can boot from it. You can edit the config.sys and
    the autoexec.bat within this directory before you start dosemu.  Fur-
    ther 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


    There is, however, one drawback, you can't use the DosC kernel
    (FreeDos) for it, because it hasn't yet a working redirector (will
    hopefully be available some time in the future).



  3.2.  How can I access the hdimage from Linux?

  Use mtools. With a line in /etc/mtools.conf like


     drive n:  file="/var/lib/dosemu/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:/con­
  fig.emu /tmp" copies the config.emu file from the hdimage to /tmp/con­
  fig.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 sunsite.unc.edu and its mirrors

       http://sunsite.unc.edu:/pub/Linux/system/filesystems/dosfs/


  A good idea is also to look in http://sun­
  site.unc.edu:/pub/Linux/Incoming for a newer version.  The "wholedisk"
  option in older versions of dosemu is no longer allowed in recent ver­
  sions, however, a line like

     $_hdimage = "/dev/hda1"


  may work, at the risk that you could lose all data in that partition
  on a dosemu crash.

  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).

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

  If LILO is installed, the above will not work.  However...

  Thomas Mockridge (thomas@aztec.co.za) reported (94/8/5) that

  To boot dosemu with LILO and Stacker 4.0 I did a little work around...

  1. dd the MBR to a file. (or norton utility, etc., first 512 bytes)

  2. Boot dos (from full boot not emu), do a fdisk /mbr, make your dos
  partition active with (dos) fdisk.

  3. Copy the new MBR to a file.

  4. Replace the original MBR

  5. Copy the second MBR to /var/lib/dosemu/partition.hda? (Whichever is
  your dos partition)

  6. Set dosemu.conf

                 disk {partition "/dev/hda? ?"}



  7. Start dosemu and and voila!  No LILO.

  For recent versions of dosemu you need to change the

                 disk {partition "/dev/hda? ?"}


  line to something like

                 $_hdimage = "/dev/hda1"


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

  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.

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

  Darren J Moffat (moffatd@dcs.gla.ac.uk) also reported (94/3/27)

  "...use 6.2 if you can get it!!  Just make sure you have a LILO boot
  disk on hand since dos 6{.2} will change the MBR of the boot HZ."

  3.4.  Creating your own hdimage file.

  The easy way is to use mkdexe - see README.txt for details.  The old-
  fashioned way (I don't know why anyone would want to do it that way
  any more but here it is, just in case) is as follows:

  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 ../doc/README.txt  and the port-section in ../etc/config.dist


  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/cua3 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 the "allowvideoportaccess on" line 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 dos -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.


  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



  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. redirect a file to dosemu standard
  input 2. use the keystroke configuration option and the -I command
  line option as described in the README.txt file to specify keystrokes
  on the command line that will act exactly as if you had typed them
  within dosemu 3. use the mkdexe program to create a DEXE file - a
  small DOS filesystem image containing just the program you want to run
  - see the README.txt file for details.

  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

  $ dos -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 termi­
  nates 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.  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.]



  7.2.  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
  "xdos" or "dos -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. Set up your X key-mappings.  In an xterm, type

       xmodmap -e "keycode 22 = 0xff08"
       xmodmap -e "keycode 107 = 0xffff"

       These lines fix the backspace and delete keys respectively.
    3. Configure the X-related configuration options in your
       /etc/dosemu.conf file.



  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. Install ansi_xterm.  The recommended package is available as:
       tsx-11.mit.edu:/pub/linux/ALPHA/dosemu/Development/ansi-xterm-R6.tar.gz

    2. Set up your X key-mappings.  In an xterm, type

       xmodmap -e "keycode 22 = 0xff08"
       xmodmap -e "keycode 107 = 0xffff"

       These lines fix the backspace and delete keys, respectively.

    3. Configure the terminal-related (not X-related) settings in
       /etc/dosemu.conf



  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"


  7.3.  Xdos dosen't 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 xdos
  on a remote display, compile dosemu with "mitshm off" in the
  compiletime-settings file after a "make pristine" or on the clean
  source tree(97/2/9).


  7.4.  Xdos dosen't 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)


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

  Look for the vga11x19 font.  (97/2/13)


  7.6.  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 (see last section)(97/2/9).


  7.7.  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.



  8.  dosemu and MS-Windows 3.1

  8.1.  Is it possible to run MS-Windows 3.1 under dosemu?

  The ../doc/README.Windows file says:


  ***************************************************************
  *    WARNING!!! WARNING!!! WARNING!!! WARNING!!! WARNING!!!   *
  *                                                             *
  *  Danger Will Robinson!!!  This is not yet fully supported   *
  *  and there are many known bugs!  Large programs will almost *
  *  certainly NOT WORK!!!  BE PREPARED FOR SYSTEM CRASHES IF   *
  *  YOU TRY THIS!!!                                            *
  *                                                             *
  *    WARNING!!! WARNING!!! WARNING!!! WARNING!!! WARNING!!!   *
  ***************************************************************



  Okay, it is possible to boot WINOS2 (the modified version of Windows
  3.1 that OS/2 uses) under DOSEMU.  Many kudos to Lutz & Dong!

  However, YOU NEED BOTH LICENSES, for WINDOWS-3.1 as well OS/2 !!!

  There are many known problems.  Windows is prone to crash, could take
  data with it, large programs will not load, etc. etc. etc.  In other
  words, it is NOT ready for daily use.  Many video cards are known to
  have problems (you may see a nice white screen, however, look below
  for win31-in-xdos).  Your program groups are all likely to disappear.
  ...  Basically, it's a pain.

  for more details see the README.txt file.


  8.2.  Can I run 32bit stuff with winemu

  Sorry, no you can't.  Win32s needs stuff running in ring 0. That's a
  "nono" with linux.  (97/04/27)



  8.3.  Errormessage: Cannot find the vdtapi.386 file when starting
  dosemu

  As explained above, winemu can't handle 32 bit stuff. All drivers
  ending in 386 are 32bit. So to run winemu, you have to delete all
  references to .386 drivers in your win.ini.  (97/04/27)


  8.4.  Windows 3.x in xdos:

  As of version 0.64.3 DOSEMU is able to run Windows in xdos. Of course,
  this is not recommended at all, but if you really want to try, it is
  safer then starting windows-31 on the console, because _when_ it
  crashes, it doesn't block your keyboard or freeze your screen.

  Hints:

  1. Get Dosemu & Linux source.
  2. Unpack dosemu.
  3. Run "./configure" to configure Dosemu (it will enable vm86plus as a
     default).
  4. Type "make" to compile.
  5. Get a 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?).
  6. Unpack the Trident drivers.
  7. In Windows setup, install the Trident "800x600 256 color for 512K
     boards" driver.
  8. Do the things described above to get and install OS2WIN31.
  10. Start xdos.
  11. In Dosemu, go to windows directory and start winemu.
  12. Cross your fingers.



  8.5.  Can I install windows from within dosemu?

  No you can't. Dos will tell you something like

       The XMS driver you have on your system is not compatible with Win­
       dows...


  You need to install windows from Dos. You can copy the windows tree to
  somewhere on your Linux Filesystem and use lredir to mount it on the
  same place as it is in dos. Example:

       You have windows in d:\windows You have d:\ mounted as /dosc in Linux
       You copy the windows tree to Linux, e.g. "cp -a /dosd/windows
       /usr/share Inside dosemu you redirect the copied tree like lredir d:
       linux\fs\dosd


  Now dosemu can't mess around in you windows directory, but changes in
  the windows directory aren't seen by dosemu too. If you want to do the
  same with windows on drive c:> look in this FAQ how to redirect c:.

  But you can use "setup" from inside the windows directory to install
  drivers and change some settings.  (97/2/1497)


  8.6.  Notes for the mouse under win31-in-xdos:

  1. Use the mouse driver "mouse.drv" from WinOS2

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

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



  3. 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. )

  4. 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)


  8.7.  Why did my Icon disappear from the Program manager?

  MS-Windows and WinOS2 handle the program manager group differently.
  While MS-Win store the setup in progman.ini, WinOS2 wants the contents
  of progman.ini in system.ini. Here's a tip from (friest@acm.org (Todd
  T. Fries)):

       cat progman.ini >> system.ini


  Be sure to use >> :-)


  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

  With the recent DPMI improvements that has gone into 0.60, you can now
  run some 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, you must have the keyboard
  configured in raw keyboard mode and enabled VGA graphics modes, in the
  /etc/dosemu.conf file.

  Note, however, you will have to turn off the sound in the game.
  (Someone will have to program in sound board emulation before we can
  avoid this).  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.rutgers.edu

  There is a security hole when having enabled DPMI and having dosemu
  suid root (especially when using dos4gw-based games), the client is
  able to access the whole user space, hence also can modify the dosemu
  code itself. Use of the 'secure' option in /etc/dosemu.conf, e.g.

       $_secure = "ngd" # secure for: n (normal users), g (guest), d (dexe)


  disables this. It is better to run dosemu as a normal user under X
  rather than root anyway.


  9.2.  Exiting from dosemu 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

  sunsite.unc.edu:/pub/Linux/libs/graphics/svgalib-1.3.1.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 src/arch/linux/debugger/README.recover and
  README.dosdebug, dosdebug can aid you recovering.


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

  Dosemu includes a rudimentary soundblaster emulator called SBemu - the
  documentation for it is currently at
  http://www.slitesys.demon.co.uk/a.macdonald/dosemu/sound/ This is a
  work in progress, not completed yet so much or most DOS software that
  uses sound will not work correctly with it yet.


  10.  Games

  10.1.  Duke3d dosen't work

  Hans Lermen <lermen@elserv.ffm.fgan.de> said (97/2/16): duke3d must be
  'configured' via a setup, within this setup you have to choose


  11.  Problems and fixes

  11.1.  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 where it is needed, and releases this right thereafter. But with
  DPMI, the Dos client programm can access the whole user space, hence
  also can modify the dosemu code itself. Use of the 'secure' option in
  /etc/dosemu.conf disables this.  There are several other important
  security considerations discussed in the Security section of the
  README.txt file.
  11.2.  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 /etc/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). If you do
  this, you should not run dosemu as root (see the Security Issues sec­
  tion) - it is better not to run dosemu as root whenever possible, in
  any case.

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


  11.3.  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)



  11.4.  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).


  11.5.  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 the "kbd_mode -a"
  command.



  11.6.  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 the config.sys file.


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

  (94/8/11)

  Grab and install klogd.  Try

           sunsite.unc.edu:/pub/Linux/system/Daemons/sysklogd1.2.tgz



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

  Aldy Hernandez (aldy@sauron.cc.andrews.edu) reported (94/7/8) that

  You should disable your video and/or BIOS caching.


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

  JyiJiin Luo (jjluo@casbah.acns.nwu.edu) reported (94/4/19) that

  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.


  11.10.  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) that

  HogThreshold should now be set to approximately half of the BogoMips
  value that the system reports on boot.



  11.11.  My CDROM drive has problems reading some files under dosemu.

  Vinod G Kulkarni (vinod@cse.iitb.ernet.in) reported (94/4/7) that

  When a CDROM is mounted from linux and used from within dosemu (mapped
  drive), there could be some problems. The CD-ROM driver (iso9660) in
  the kernel tries to find out the type of the file (i.e. binary or
  text).  If it can't find, it tries to guess the type of the file using
  a heuristic. This heuristic fails under some circumstances when a
  (almost) text file is to be treated as binary.  (I do not know if it
  is a bug or feature.)

  The result of this is that if you copy such a file from CD-ROM (from
  linux itself, and not necessarily dosemu), the resulting file will be
  usually bigger than original file. (Blanks get added before ^J,^M.)
  So a program running in dosemu gives an error or hangs, which may be
  mistaken as problem of dosemu.

  Rob Janssen (pe1chl@rabo.nl) reported (94/8/10) that

  The way to solve this is to turn off conversion altogether.  Pass the
  option "-o conv=binary" to the mount command mounting the CD-ROM, or
  use the following in /etc/fstab:

  /dev/cdrom      /cdrom          iso9660 conv=binary,ro


  No patches to the kernel are necessary.


  11.12.  How do I see debugging output?

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

  As of dosemu 0.60, debugging output is redirected to a file specified
  on the command line.  Use "dos -D+a -o /tmp/debug" to log all debug
  output to /tmp/debug.  There should no longer be any need to redirect
  stderr.



  11.13.  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).


  11.14.  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)


  11.15.  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 disk { partition ... } in
  /etc/dosemu/conf, it runs.

  12.  Contributing to the dosemu project

  12.1.  Who is responsible for dosemu?


  Dosemu is built upon the work of Matthias Lautner and Robert Sanders.
  Hans Lermen (lermen@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



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

  The dosemu project is a team effort.  If you wish to contribute, see
  the DPR (dosemu Project Registry).  A current copy may be found in
  doc/DANG.



