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Dos Subsystem

Posted: Mon Nov 28, 2005 10:42 pm
by crashfourit
I'm interested in starting to code the DOS subsystem.

So I am going to list some possible design principles:

Avoid excessive switching from V86 mode and Protected mode.
Limit direct access to system hardware by DOS programs (especially IO).
Must differentiate CPU exceptions and Software interrupts.
Each DOS process would have its own private first Megabyte of Memory.
At least DPMI v. 0.9 support.
Dos API support (Including Long File Name support.)

Possible design additions:
Native handling of DJGPP DPMI programs (I.E. skip DJGPP stub-loader and jump directly to the DJGPP COFF image).
Open GEM GUI API Support.
Bios and Video ROM virtualization.

Additions, subtractions, modifications, or comments anyone?

Posted: Tue Nov 29, 2005 2:43 am
by oiaohm
Ok dosbox.sf.net. Will help a little. It has speed issues but it will run windows 3.11 in side its self.

Good starting point. Sub system links to dosbox could improve performance.

Posted: Tue Nov 29, 2005 6:28 am
by cmoibenlepro
BTW, scuse me if I'm off topic, but why do we need a dos subsystem?
I don't know why a user would be interested in running old dos programs made 10-15 years ago...

Dos is like a dinosaur, isn't it?

:?:

Posted: Tue Nov 29, 2005 6:55 am
by oiaohm
Said thing is that dos is not dead yet.

Programs from Win9x systems use dos calls in places.

Freedos is still alive and kicking. Its getting harder to kill stuff. Microsoft might think they killed dos but it did not die.

Yes and this is a little off topic from the graphical point of view. Open Gem is a new system not a old one.

Posted: Tue Nov 29, 2005 12:00 pm
by ScoTTie
cmoibenlepro, quite alot of custom made business applications still require DOS. Even today i still see some smaller shops using old DOS POS applications. Not to mention all the classic games id love to run without the need of an emulator (ala DosBox)

Posted: Thu Dec 01, 2005 4:24 pm
by witukind
ReactOS is NT not 9x. Really I wouldn't care at all for DOS compatibility when I can just install FreeDOS and have compatibility and speed. And btw... DosBox is a neatly designed and self-contained piece of software, and it's performance is just great. Runs very nicely even on a P200, so what's wrong about it?

Re: Dos Subsystem

Posted: Thu Dec 01, 2005 6:37 pm
by loki1985
crashfourit wrote:Limit direct access to system hardware by DOS programs (especially IO).
i think DOS programs should have NO direct hardware access at all, since then they could eventually crash the system / make it unstable (at least no unattended access).

maybe some sort of supervising could take place, or, much better, emulate the direct access....

Posted: Fri Dec 02, 2005 3:31 pm
by Mrkaras
Can the dos programs think they have full direct hardware access while actualy using the proper api chennels, like the first mb of memory, they think it is the first MB there using but it is not actualy the first MB of ram.

I think a dos subsystem would be an inportant addition to reactos. dos game networking would be good (IPX direct hardware access i think).

Posted: Tue May 02, 2006 4:11 pm
by m1423
Don't forget about one of DOS's more powerful features, the wildcard. Very useful when you have a lot of files and you only need to do something with some of them. DOS is needed, don't leave it out.

Posted: Tue May 02, 2006 4:41 pm
by Phalanx
m1423 wrote:Don't forget about one of DOS's more powerful features, the wildcard. Very useful when you have a lot of files and you only need to do something with some of them. DOS is needed, don't leave it out.
That is got to do with the shell, not DOS.

Posted: Tue May 02, 2006 5:42 pm
by Harteex
I would really love to see a DOS subsystem.
DOSBox is too slow... some of my DOS games are very slow with it on my Amd64 2000+.

Posted: Tue May 02, 2006 10:15 pm
by EmuandCo
Hmm a DOS Subsystem... Settlers on ReactOS.... hmmmm

Posted: Wed May 03, 2006 12:42 am
by Harteex
EmuandCo wrote:Hmm a DOS Subsystem... Settlers on ReactOS.... hmmmm
mm.. Settlers II Gold Edition.. :)


crashfourit: Are you still interested in coding this or have you dropped the idea?

Posted: Wed May 03, 2006 9:53 am
by GreatLord
We have part of dos system in ros
om NT it call VDM finish it u maybe can run old games
I prefer using dosbox

Posted: Wed May 03, 2006 12:17 pm
by Dr. Fred
GreatLord wrote:We have part of dos system in ros
om NT it call VDM finish it u maybe can run old games
I prefer using dosbox
Our current subsystem is just a stub which does nothing yet. We do not even have the functionality in the kernel. I think the reactos project has other priorities at the moment.