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From: jca@pnet01.cts.com (John C. Archambeau)
Newsgroups: comp.sys.ibm.pc
Subject: Re: UNIX runs DOS applications?
Message-ID: <754@crash.cts.com>
Date: 23 Nov 89 08:16:04 GMT
Sender: root@crash.cts.com
Organization: People-Net [pnet01], El Cajon CA
Lines: 65

rcd@ico.isc.com (Dick Dunn) writes:
>jca@pnet01.cts.com (John C. Archambeau) writes:
>> mitsolid@acf5.NYU.EDU (Thanasis Mitsolides) writes:
>> >Is it possible to run DOS sessions from inside UNIX?
>...
>> Yes, SunOS 4.0.x on a Sun 386i (or a Sun with a Sun IPC board) will do the job
>> nicely.  Too pricy for you?  Ok, get SCO ...
>[various items about VP/ix]
>
>You could also try Interactive's 386/ix.  Note - there are various places
>where VP/ix shows up in other products--Sun's 386i essentially uses VP/ix,
>for example.  VP/ix is *not* a generic name for DOS-under-UNIX, though...
>there are other such animals.  VP/ix was developed by (and is a trademark
>of) Interactive and Phoenix.
 
DOS Windows isn't essentially VP/ix, it *IS* VP/ix.  Along with what SCO uses
in Xenix and I believe Unix.  Since I have great faith in both Sun and SCO
(personal bias here) than I do in any other product, to me DOS-under-Unix is
VP/ix or it isn't DOS-under-Unix at all.  This is sort of how the term
"household name" got started.  I am well aware of the trademark and copyrights
of who owns VP/ix, but the awareness really hit home when SCO and Sun both
license it from Interactive and Phoenix in their *nix implementations.

>> ...But I would not run any sort of implementation of VP/ix
>> (i.e. DOS Windows) on a 286 box because the 286 is brain damaged with respect
>> to flipping in and out of protect mode, that and there's no virtual 8086 mode
>> like the 386 has...
>
>This is quite off.  VP/ix is a facility which works in a 386 UNIX system,
>period.  The question of running VP/ix on a 286 simply cannot arise,
>because you cannot run a 386 UNIX system on a 286.  But beyond that, VP/ix
>makes explicit use of "virtual 8086 mode" which (as correctly noted) does
>not exist on a 286.
 
Then what does SCO use for DOS Windows on SCO Xenix 286?  I'm sure that there
is a brain damaged 286 version of it out there, but it is known to crash.  I
don't remember for sure if it's VP/ix or not, but it wouldn't surprise me if
Interactive and Phoenix tried it just once to see if they could break the
rules.  Anybody who has used DOS Windows under SCO Xenix 286 will agree after
a few crashes that Xenix 286 isn't meant to run DOS sessions, period.  Either
you put it in protect mode and leave it there, or leave it in 8086 mode. 
Regardless of whether or not VP/ix has a 286 version or not, one can run DOS
Windows from SCO Xenix 286.  There's no guarantee how long before it will
crash, but it is guaranteed from one that knows the 286 well that it will
crash.  Again, no offense to the makers of VP/ix or SCO, but one can not get
around the flaws of the 286.

>(I suspect that when Archambeau said "any sort of implementation of VP/ix"
>he really meant "any sort of DOS-under-UNIX"--which is not the same
>thing.)

Yes, that was what I was driving at.

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