[comp.windows.ms.programmer] Protected mode in virtual machines

klb@stiatl.UUCP (Kathy Ball) (01/26/91)

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

ed@odi.com (Ed Schwalenberg) (01/28/91)

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.

The VMM is documented in the Device Driver Development Kit, which is available
from Microsoft for $500; there's an order form for it in the SDK.

You're "not supposed to" program virtual machines yourself; the DDK has
all this info so that virtual devices can handle requests from multiple
VMs.  You're supposed to use a protected-mode DOS extender (like the one
from Phar Lap) which in turn uses the DPMI (DOS Protected-Mode Interface)
spec to get Windows' cooperation in sharing protected-mode resources.

matts@microsoft.UUCP (Matt SAETTLER) (02/01/91)

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...

jporter@twaddle.dell.com (Jeff Porter) (02/07/91)

The Dos Protected Mode Interface Specification distributed by:

DPMI Committee Secretary
Software Focus Group
Intel Corporation, NW1-18
2801 Northwestern Parkway
Santa Clara, CA 95051

Intel order Number: 240743-001

Call Intel Literature JP26 at 1-800-548-4725.



Jeff Porter