Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!microsoft!matts
From: matts@microsoft.UUCP (Matt SAETTLER)
Newsgroups: comp.windows.ms.programmer
Subject: Re: Protected mode in virtual machines
Keywords: 386 Enhanced, Protected mode, virtual machine
Message-ID: <70365@microsoft.UUCP>
Date: 31 Jan 91 20:44:31 GMT
References: <329@stiatl.UUCP<
Reply-To: matts@microsoft.UUCP (Matt SAETTLER)
Organization: Microsoft Corp., Redmond WA
Lines: 34

In article <329@stiatl.UUCP< klb@stiatl.UUCP (Kathy Ball) writes:
<I'm looking for documentation about the Virtual Machine Manager that
<creates virtual machines in 386 enhanced mode.  Is it really possible
<to run a non-Windows application in protected mode?  I've searched diligently
<through all the manuals I could find, but located virtually (sorry :-)
<nothing about virtual machines.
<
<The thing that made me think it was even a possibility was an obscure 
<passage from the July 1990 issue of _Microsoft Systems Journal_, page 12:
<
<"In particular, Windows 3.0 virtual machines include not only the
<virtual 8086 environment that the 386 hardware provides, but also an
<optional protected-mode portion.  The first virtual machine created--
<the System VM--has a protected-mode portion used for running Windows
<applications.  Other virtual machines may have only an 8086 (DOS) portion,
<but they can just as easily have a protected-mode portion, allowing
<other kinds of protected-mode applications to run in 386 enhanced mode."
<
<Has anyone used this feature?  Does it cause any problems?  How do you
<harness the beast?
<
<Thanks,
<Kathy Ball

'Harnessing' is accomplished using DPMI (DOS Protect Mode Interface).
This API was originally developed at Microsoft to allow multiple
virtual protect mode DOS machines.  The API is now being evolved
by committee and is available from Intel. (sorry, no address handy).

This API is very low-level (change CS segment into selector, etc).

MattS

I speak only for myself, or so I'm told to say...