From:	"Alexei A. Frounze" <alex DOT fru AT mtu-net DOT ru>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Multitasking: executing some EXE-files (nearly) simultaneously
Date:	Mon, 27 Mar 2000 21:05:36 +0400
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To:	djgpp AT delorie DOT com
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Reply-To:	djgpp AT delorie DOT com

Are you sure you need *2 separate EXE programs* but not 2 threads?

Just keep in mind that MSDOS and DOS box in MSWindows does not provide
reenterablity of the service functions. I.e. in order to run normal
programs simultaneously you simplly have to write your own OS with full
MSDOS support.

But...

You may split your program into 2 (or more) semi/fully independant
threads and switch
betweenm them regardless of compiler you use and OS you work under. It's
a simple stack switching stuff. You may find an example program of doing
that (Borland Pascal/Turbo Assembler sources - 9KBs only) at my
homepage. Look for it in the "General programming" section.

Btw, I recommend you to refer news:comp.lang.asm.x86 and
news:alt.os.development instead of DJGPP related NGs for such questions.

Regards.
Alexei A. Frounze

Homepage: http://alexfru.chat.ru
Mirror:   http://members.xoom.com/alexfru

> > A very interesting (=difficult to impossible) topic of
> > programming with (MS)-DOS is multitasking. My idea was to
> > execute two or more EXE-files (nearly) at the same time by
> > reading them manually into RAM, interpreting&executing some
> > commands, saving all the registers into RAM, then switching
> > to the other application, restoring its previously saved
> > CPU registers and executing some commands and so on...
> > Does anybody have any idea how this could be made work?

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