DOSBox emulator system files

Question

I use Ubuntu Studio 20.04.2 LTS and DOSBox 0.74-3 emulator.

I created a folder called "DOS" at the main mounted "C:" virtual HDD and I put inside that folder all the DOS system program files from the old MS-DOS 6.22.

I'm talking about system programs like "KEYB", "MEM", etc.

Now, each time I want to use those old MS-DOS system program files, the emulator tells me: "Incorrect DOS version".

I assume (just guessing) that the emulator is reading from the "new" DOS folder now, and not from the original DOSBox system files folder.

How can I get the emulator get back to read from the original DOSBox system files folder?

Where is that folder?

This is the DOSbox configuration file:

# This is the configuration file for DOSBox 0.74-3. (Please use the latest version of DOSBox)
# Lines starting with a # are comment lines and are ignored by DOSBox.
# They are used to (briefly) document the effect of each option.
[sdl]
fullscreen: Start dosbox directly in fullscreen. (Press ALT-Enter to go back)
fulldouble: Use double buffering in fullscreen. It can reduce screen flickering, but it can also result in a slow DOSBox.
fullresolution: What resolution to use for fullscreen: original, desktop or fixed size (e.g. 1024x768).
Using your monitor's native resolution (desktop) with aspect=true might give the best results.
If you end up with small window on a large screen, try an output different from surface.
On Windows 10 with display scaling (Scale and layout) set to a value above 100%, it is recommended
to use a lower full/windowresolution, in order to avoid window size problems.
windowresolution: Scale the window to this size IF the output device supports hardware scaling.
(output=surface does not!)
output: What video system to use for output.
Possible values: surface, overlay, opengl, openglnb.
autolock: Mouse will automatically lock, if you click on the screen. (Press CTRL-F10 to unlock)
sensitivity: Mouse sensitivity.
waitonerror: Wait before closing the console if dosbox has an error.
priority: Priority levels for dosbox. Second entry behind the comma is for when dosbox is not focused/minimized.
pause is only valid for the second entry.
Possible values: lowest, lower, normal, higher, highest, pause.
mapperfile: File used to load/save the key/event mappings from. Resetmapper only works with the default value.
usescancodes: Avoid usage of symkeys, might not work on all operating systems.
fullscreen=false
fulldouble=false
fullresolution=original
windowresolution=original
output=surface
autolock=true
sensitivity=100
waitonerror=true
priority=higher,normal
mapperfile=mapper-0.74-3.map
usescancodes=true
[dosbox]
language: Select another language file.
machine: The type of machine DOSBox tries to emulate.
Possible values: hercules, cga, tandy, pcjr, ega, vgaonly, svga_s3, svga_et3000, svga_et4000, svga_paradise, vesa_nolfb, vesa_oldvbe.
captures: Directory where things like wave, midi, screenshot get captured.
memsize: Amount of memory DOSBox has in megabytes.
This value is best left at its default to avoid problems with some games,
though few games might require a higher value.
There is generally no speed advantage when raising this value.
language=
machine=svga_s3
captures=capture
memsize=63
[render]
frameskip: How many frames DOSBox skips before drawing one.
aspect: Do aspect correction, if your output method doesn't support scaling this can slow things down!
scaler: Scaler used to enlarge/enhance low resolution modes. If 'forced' is appended,
then the scaler will be used even if the result might not be desired.
To fit a scaler in the resolution used at full screen may require a border or side bars,
to fill the screen entirely, depending on your hardware, a different scaler/fullresolution might work.
Possible values: none, normal2x, normal3x, advmame2x, advmame3x, advinterp2x, advinterp3x, hq2x, hq3x, 2xsai, super2xsai, supereagle, tv2x, tv3x, rgb2x, rgb3x, scan2x, scan3x.
frameskip=0
aspect=true
scaler=normal2x
[cpu]
core: CPU Core used in emulation. auto will switch to dynamic if available and
appropriate.
Possible values: auto, dynamic, normal, simple.
cputype: CPU Type used in emulation. auto is the fastest choice.
Possible values: auto, 386, 386_slow, 486_slow, pentium_slow, 386_prefetch.
cycles: Amount of instructions DOSBox tries to emulate each millisecond.
Setting this value too high results in sound dropouts and lags.
Cycles can be set in 3 ways:
'auto'          tries to guess what a game needs.
It usually works, but can fail for certain games.
'fixed #number' will set a fixed amount of cycles. This is what you usually
need if 'auto' fails. (Example: fixed 4000).
'max'           will allocate as much cycles as your computer is able to
handle.
Possible values: auto, fixed, max.
cycleup: Amount of cycles to decrease/increase with keycombos.(CTRL-F11/CTRL-F12)
cycledown: Setting it lower than 100 will be a percentage.
core=auto
cputype=auto
cycles=auto
cycleup=10
cycledown=20
[printer]
printer: Enable printer emulation.
dpi: Resolution of printer (default 300).
width: Width of paper in 1/10 inch (default 85 = 8.5'').
height: Height of paper in 1/10 inch (default 110 = 11.0'').
printoutput: Output method for finished pages:
png     : Creates PNG images (default)
ps      : Creates Postscript
bmp     : Creates BMP images (very huge files, not recommend)

multipage: Adds all pages to one Postscript file or printer job until CTRL-F2 is pressed.
docpath: The path where the output files are stored.
timeout: (in milliseconds) if nonzero: the time the page will
be ejected automatically after when no more data
arrives at the printer.
printer=true
dpi=72
width=85
height=130
printoutput=png
multipage=false
timeout=0
[mixer]
nosound: Enable silent mode, sound is still emulated though.
rate: Mixer sample rate, setting any device's rate higher than this will probably lower their sound quality.
Possible values: 44100, 48000, 32000, 22050, 16000, 11025, 8000, 49716.
blocksize: Mixer block size, larger blocks might help sound stuttering but sound will also be more lagged.
Possible values: 1024, 2048, 4096, 8192, 512, 256.
prebuffer: How many milliseconds of data to keep on top of the blocksize.
nosound=false
rate=44100
blocksize=1024
prebuffer=25
[midi]
mpu401: Type of MPU-401 to emulate.
Possible values: intelligent, uart, none.
mididevice: Device that will receive the MIDI data from MPU-401.
Possible values: default, win32, alsa, oss, coreaudio, coremidi, none.
midiconfig: Special configuration options for the device driver. This is usually the id of the device you want to use
(find the id with mixer/listmidi).
Or in the case of coreaudio, you can specify a soundfont here.
See the README/Manual for more details.
mpu401=intelligent
mididevice=default
midiconfig=
[sblaster]
sbtype: Type of Soundblaster to emulate. gb is Gameblaster.
Possible values: sb1, sb2, sbpro1, sbpro2, sb16, gb, none.
sbbase: The IO address of the soundblaster.
Possible values: 220, 240, 260, 280, 2a0, 2c0, 2e0, 300.
irq: The IRQ number of the soundblaster.
Possible values: 7, 5, 3, 9, 10, 11, 12.
dma: The DMA number of the soundblaster.
Possible values: 1, 5, 0, 3, 6, 7.
hdma: The High DMA number of the soundblaster.
Possible values: 1, 5, 0, 3, 6, 7.
sbmixer: Allow the soundblaster mixer to modify the DOSBox mixer.
oplmode: Type of OPL emulation. On 'auto' the mode is determined by sblaster type. All OPL modes are Adlib-compatible, except for 'cms'.
Possible values: auto, cms, opl2, dualopl2, opl3, none.
oplemu: Provider for the OPL emulation. compat might provide better quality (see oplrate as well).
Possible values: default, compat, fast.
oplrate: Sample rate of OPL music emulation. Use 49716 for highest quality (set the mixer rate accordingly).
Possible values: 44100, 49716, 48000, 32000, 22050, 16000, 11025, 8000.
sbtype=sb16
sbbase=220
irq=7
dma=1
hdma=5
sbmixer=true
oplmode=auto
oplemu=default
oplrate=44100
[gus]
gus: Enable the Gravis Ultrasound emulation.
gusrate: Sample rate of Ultrasound emulation.
Possible values: 44100, 48000, 32000, 22050, 16000, 11025, 8000, 49716.
gusbase: The IO base address of the Gravis Ultrasound.
Possible values: 240, 220, 260, 280, 2a0, 2c0, 2e0, 300.
gusirq: The IRQ number of the Gravis Ultrasound.
Possible values: 5, 3, 7, 9, 10, 11, 12.
gusdma: The DMA channel of the Gravis Ultrasound.
Possible values: 3, 0, 1, 5, 6, 7.
ultradir: Path to Ultrasound directory. In this directory
there should be a MIDI directory that contains
the patch files for GUS playback. Patch sets used
with Timidity should work fine.
gus=false
gusrate=44100
gusbase=240
gusirq=5
gusdma=3
ultradir=C:\ULTRASND
[speaker]
pcspeaker: Enable PC-Speaker emulation.
pcrate: Sample rate of the PC-Speaker sound generation.
Possible values: 44100, 48000, 32000, 22050, 16000, 11025, 8000, 49716.
tandy: Enable Tandy Sound System emulation. For 'auto', emulation is present only if machine is set to 'tandy'.
Possible values: auto, on, off.
tandyrate: Sample rate of the Tandy 3-Voice generation.
Possible values: 44100, 48000, 32000, 22050, 16000, 11025, 8000, 49716.
disney: Enable Disney Sound Source emulation. (Covox Voice Master and Speech Thing compatible).
pcspeaker=true
pcrate=44100
tandy=auto
tandyrate=44100
disney=true
[joystick]
joysticktype: Type of joystick to emulate: auto (default), none,
2axis (supports two joysticks),
4axis (supports one joystick, first joystick used),
4axis_2 (supports one joystick, second joystick used),
fcs (Thrustmaster), ch (CH Flightstick).
none disables joystick emulation.
auto chooses emulation depending on real joystick(s).
(Remember to reset dosbox's mapperfile if you saved it earlier)
Possible values: auto, 2axis, 4axis, 4axis_2, fcs, ch, none.
timed: enable timed intervals for axis. Experiment with this option, if your joystick drifts (away).
autofire: continuously fires as long as you keep the button pressed.
swap34: swap the 3rd and the 4th axis. Can be useful for certain joysticks.
buttonwrap: enable button wrapping at the number of emulated buttons.
joysticktype=auto
timed=true
autofire=false
swap34=false
buttonwrap=false
[serial]
serial1: set type of device connected to com port.
Can be disabled, dummy, modem, nullmodem, directserial.
Additional parameters must be in the same line in the form of
parameter:value. Parameter for all types is irq (optional).
for directserial: realport (required), rxdelay (optional).
(realport:COM1 realport:ttyS0).
for modem: listenport (optional).
for nullmodem: server, rxdelay, txdelay, telnet, usedtr,
transparent, port, inhsocket (all optional).
Example: serial1=modem listenport:5000
Possible values: dummy, disabled, modem, nullmodem, directserial.
serial2: see serial1
Possible values: dummy, disabled, modem, nullmodem, directserial.
serial3: see serial1
Possible values: dummy, disabled, modem, nullmodem, directserial.
serial4: see serial1
Possible values: dummy, disabled, modem, nullmodem, directserial.
serial1=dummy
serial2=dummy
serial3=disabled
serial4=disabled
[dos]
xms: Enable XMS support.
ems: Enable EMS support.
umb: Enable UMB support.
keyboardlayout: Language code of the keyboard layout (or none).
xms=true
ems=true
umb=true
keyboardlayout=auto
keyb la 437
[ipx]
ipx: Enable ipx over UDP/IP emulation.
ipx=false
[autoexec]
Lines in this section will be run at startup.
You can put your MOUNT lines here.
mount c: /media/jjpg/SISTEMA/DOS/

Answer 1

In my environment the drive Z:\ contains some system files used by DOSBox, so the PATH variable is set to Z:\. Enter the PATH, SET, or MOUNT command to find out about your environment.

For more information see: https://www.dosbox.com/wiki/ZDrive

Please Note: in DOS (contrary to Linux practice), if there is a file with the same name in the current directory, this file will be executed instead of the one in the PATH.

For example, if there is a file called MEM.COM or MEM.EXE in your current directory and you enter the command MEM, the file in the current directory and not the one in Z:\ will be executed. To execute the file in Z:\, you should either

• Enter the full path as a command (e.g. Z:\MEM, assuming the relevant DOSBox command is in Z:\)

or

• Change to another directory that does not contain an executable file with name MEM.COM or MEM.EXE (assuming your PATH variable is correctly set to point to the directory containing the relevant DOSBox command, e.g. PATH=Z:\).