DOSBox v0.72 - Contact

See the site:
http://dosbox.sourceforge.net
for an email address (The Crew-page).

DOSBox v0.72 - Special thanks

See the THANKS file.

DOSBox v0.72 - Building your own version of DOSBox

Download the source.
Check the INSTALL in the source distribution.

DOSBox v0.72 - The Language File

A language file can be generated by CONFIG.COM (CONFIG -writelang langfile).
Read it, and you will hopefully understand how to change it.
Start DOSBox with the -lang switch to use your new language file.
Alternatively, you can setup the filename in the config file in the [dosbox]
section. There's a language= entry that can be changed with the filename.

DOSBox v0.72 - The Config File

A config file can be generated by CONFIG.COM, which can be found on the
internal DOSBox Z: drive when you start up DOSBox. Look in the internal
programs section of the readme for usage of CONFIG.COM.
You can edit the generated configfile to customize DOSBox.
The file is divided into several sections (the names have [] around it).
Some sections have options you can set.
# and % indicate comment-lines.
The generated configfile contains the current settings. You can alter them and
start DOSBox with the -conf switch to load the file and use these settings.
DOSBox will first parse the settings in ~/.dosboxrc (Linux),
~\dosbox.conf (Win32) or "~/Library/Preferences/DOSBox Preferences"
(MACOSX). Afterwards DOSBox will parse all configfiles specified with the
-conf switch. If no configfile is specified with the -conf switch, DOSBox will
look in the current directory for dosbox.conf.

DOSBox v0.72 - Troubleshooting

DOSBox crashes right after starting it:
- use different values for the output= entry in your DOSBox
configuration file
- try to update your graphics card driver and DirectX
Running a certain game closes DOSBox, crashes with some message or hangs:
- see if it works with a default DOSBox installation
(unmodified configuration file)
- try it with sound disabled (use the sound configuration
program that comes with the game, additionally you can
set sbtype=none and gus=false in the DOSBox configuration file)
- change some entries of the DOSBox configuration file, especially try:
core=normal
fixed cycles (for example cycles=10000)
ems=false
xms=false
or combinations of the above settings
- use loadfix before starting the game
The game exits to the DOSBox prompt with some error message:
- read the error message closely and try to locate the error
- try the hints at the above sections
- mount differently as some games are picky about the locations,
for example if you used "mount d d:\oldgames\game" try
"mount c d:\oldgames\game" and "mount c d:\oldgames"
- if the game requires a CD-ROM be sure you used "-t cdrom" when
mounting and try different additional parameters (the ioctl,
usecd and label switches, see the appropriate section)
- check the file permissions of the game files (remove read-only
attributes, add write permissions etc.)
- try reinstalling the game within DOSBox

DOSBox v0.72 - How to run resource-demanding games

DOSBox emulates the CPU, the sound and graphic cards, and other peripherals
of a PC, all at the same time. The speed of an emulated DOS application
depends on how many instructions can be emulated, which is adjustable
(number of cycles).
CPU Cycles
By default (cycles=auto) DOSBox tries to detect whether a game needs to
be run with as many instructions emulated per time interval as possible.
You can force this behaviour by setting cycles=max in the DOSBox
configuration file. The DOSBox window will display a line "Cpu Cyles: max"
at the top then. In this mode you can reduce the amount of cycles on a
percentage-basis (hit CTRL-F11) or raise it again (CTRL-F12).

Sometimes manually setting the number of cycles achieves better results,
in the DOSBox configuration file specify for example cycles=30000. When
running some DOS application you can raise the cycles with CTRL-F12 even
more, but you will be limited by the power of your actual CPU. You can see
how much free time your true CPU has by looking at the Task Manager in
Windows 2000/XP and the System Monitor in Windows 95/98/ME. Once 100% of
your real CPU time is used there is no further way to speed up DOSBox
unless you reduce the load generated by the non-CPU parts of DOSBox.
CPU Cores
On x86 architectures you can try to force the usage of a dynamically
recompiling core (set core=dynamic in the DOSBox configuration file).
This usually gives better results if the auto detection (core=auto) fails.
It is best accompanied by cycles=max. Note that there might be games
that work worse with the dynamic core, or do not work at all!
Graphics emulation
VGA emulation is a very demanding part of DOSBox in terms of actual CPU
usage. Increase the number of frames skipped (in increments of one) by
pressing CTRL-F8. Your CPU usage should decrease when using a fixed
cycle setting.
Go back one step and repeat this until the game runs fast enough for you.
Please note that this is a trade-off: you lose in fluidity of video what
you gain in speed.
Sound emulation
You can also try to disable the sound through the setup utility of the game
to reduce load on your CPU further. Setting nosound=true does NOT disable
the emulation of sound devices, just the sound output will be disabled.
Also try to close every program but DOSBox to reserve as much resources
as possible for DOSBox.
Advanced cycles configuration:
The cycles=auto and cycles=max settings can be parameterized to have
different startup defaults. The syntax is
cycles=auto ["realmode default"] ["protected mode default"%]
[limit "cycle limit"]
cycles=max ["protected mode default"%] [limit "cycle limit"]
Example:
cycles=auto 1000 80% limit 20000
will use cycles=1000 for real mode games, 80% CPU throttling for
protected mode games along with a hard cycle limit of 20000