From: pausch AT merope DOT saaf DOT se (Paul Schlyter)
Newsgroups: comp.os.msdos.djgpp,comp.os.msdos.programmer,comp.protocols.tcp-ip.ibmpc
Subject: Re: An updated DOS - Please discuss
Date: 16 Sep 1999 08:42:42 +0200
Organization: Svensk Amat|rAstronomisk F|rening (SAAF)
Lines: 33
Message-ID: <7rq3h2$3p4$1@merope.saaf.se>
References: <37d7913a DOT 10901976 AT news-reader DOT bt DOT net> <37ddafe0 DOT 858354 AT news-reader DOT bt DOT net> <7rks8h$1llt$1 AT Mars DOT mcs DOT net> <37dfba17 DOT 26621229 AT news-reader DOT bt DOT net>
NNTP-Posting-Host: merope.saaf.se
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

In article <37dfba17 DOT 26621229 AT news-reader DOT bt DOT net>,
Michael Kearns <michael AT toobie DOT demon DOT co DOT uk> wrote:
> On 14 Sep 1999 02:08:01 -0500, les AT Mars DOT mcs DOT net (Leslie Mikesell) wrote:
> 
>> But the whole point of DOS is that it just loads applications and
>> lets them take over the machine.  If you enhance it, it won't
>> be DOS anymore and it will probably be a lot worse than the
>> well tested alternatives.
> 
> If that were the case, you could never *ever* have a dos emulation under
> another operating system. After all, does Linux unload itself when using
> DOSEmu ? I don't think so.
 
One can emulate DOS under another system, even if the DOS programs
think they own the machine and access hardware directly: I/O
instructions performed by a DOS program running under an emulator can
be trapped by the real OS, which then does some work "behind the
scenes" and finally leaves some data for the DOS program to read.  To
the DOS program it will appear as it actually had accessed the
hardware, and that it worked!
 
> The whole point of DOS at the time of it's conception, was that it was the
> OS for the x86. (There may have been a few others, I don't know).
 
The original IBM PC offered two alternatives to MS-DOS:  CP/M-86 and
UCSD Pascal.
 
-- 
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