*BSD News Article 19273


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From: blymn@awadi.com.au (Brett Lymn)
Newsgroups: comp.os.386bsd.development
Subject: Re: V86 mode
Date: 08 Aug 1993 09:01:14 GMT
Organization: AWA Defence Industries Pty. Ltd.
Lines: 25
Distribution: world
Message-ID: <BLYMN.93Aug8183114@siren.awadi.com.au>
References: <107725@hydra.gatech.EDU> <23tqbk$3tt@europa.eng.gtefsd.com>
NNTP-Posting-Host: siren.awadi.com.au
In-reply-to: niemidc@oasis.gtefsd.com's message of 6 Aug 1993 14:37:40 GMT

>>>>> On 6 Aug 1993 14:37:40 GMT, niemidc@oasis.gtefsd.com (David C. Niemi) said:
David> NNTP-Posting-Host: hengist.lab.oasis.gtegsc.com

David> The V86-mode emulators I have seen tend to suck about 10% of the CPU each (on a 386).
David> Is this inherent in V86 mode, or is it a deficiency of the implementation?
David> In other words, have you gotten around this problem?

The problem with DOS (and/or the applications thereunder) is that it
expects to have the entire machine to itself and hence does dumb cycle
wasting things like polling.  From my understanding of dos-under-unix
programs they try and restrain this behaviour by lowering the priority
of the task if they detect a polling loop.

I am attempting to port the Linux dosemu (actually xdos), my main
stumbling block at the moment is lack of kernel services such as shm,
sem and msg and of course v86.  I am, at the moment, trying to work
out how to get these services into the kernel with the least amount of
effort.  I have looked at the sources for Linux but I will need to get
the authors permission to use them.  I have also mailed Bill Jolitz
regarding this.  If anyone has any suggestions/help to get the stuff I
need it will be most welcome.


--
Brett Lymn