From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: DJGPP Support Dual Processor?
Date:	Thu, 23 Sep 1999 11:18:24 +0200
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On Wed, 22 Sep 1999, Duncan Coutts wrote:

> DJGPP runs using DPMI which has many nice features such as memory
> protection, virtual memory, but it is still Dos single tasking.

There's nothing inherently single-tasking about DPMI.  As a matter of
fact, Caldera's DR-DOS already supports multi-tasking with its DPMI
host.

> Win95+, Unix and other more advanced OSs support multitasking
> (pre-emptive, not co-operative) by using multiple threads. Some OS's
> (WinNT & probably some Unix versions) can take advantage of multiple
> processors by allowing different threads to run on different
> processors.

It is still possible that e.g. all system calls run on a different
processor.  This requires that the underlying OS supports such a
feature, but DJGPP won't prevent it from happening.

> Any multitasking is platform specific and therefore non-portable.
> Unfortunately for you, DJGPP's platform has no such features.

Actually, there are a couple of threading packages that work with
DJGPP.  Check out section 22.3 of the DJGPP FAQ list.

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