Date:	Sat, 08 Feb 2003 19:04:06 +0200
From:	"Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
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To:	djgpp AT delorie DOT com
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	(sjmccaug AT bluestem DOT prairienet DOT org)
Subject:	Re: Generate real-mode 386 DOS executables?
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> From: "Scott J. McCaughrin" <sjmccaug AT bluestem DOT prairienet DOT org>
> Newsgroups: comp.os.msdos.djgpp
> Date: Sat, 8 Feb 2003 16:28:30 +0000 (UTC)
> 
>  The question remains: is DJGPP really for MS-DOS?

Yes.

>  If so, then I should be able to make 16-bit INT 21h DOS function
>  calls.

DJGPP _does_ issue INT 21h DOS calls (how else do you think it does
file I/O?), but it does so via the DPMI (DOS Protected-Mode)
interface, which is implemented as a bunch of functions of INT 31h.
The DPMI server, a special piece of software required by DJGPP
programs to run, is then responsible to convert INT 31h calls from
protected mode into INT 21h calls in real mode.

>  If I cannot make such calls, it is really not DOS-compliant. So
>  which is it?

DJGPP produces 32-bit protected-mode programs that run on top of DOS.
It is compliant with DOS in the sense that programs it produces use
DOS services and run on DOS machines.

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