Subject: Re: VM86 stuff: how faithful to Linux interface?
To: None <>
From: Terry Moore <>
List: port-i386
Date: 03/13/1995 14:25:12
> Comments, suggestions, etc?

Our experience at Databook working within the Windows environment would
indicate that the folks working on WINES will be able to do many more
interesting things if you support the entire 64K-bit I/O space map.
This would allow you to provide for emulating VxDs and so forth.  I
understand why you'd want to avoid that overhead, but....  best to
bite the bullet now.  I don't know how or when TSS's get allocated
within NetBSD, nor how hard it is to enlarge them if needed; but 8K
in order to provide higher-fidelity emulation would be well worth
while.  Also, as a research OS, NetBSD is my candidate for hosting
some other virtual x86 environment projects, for developing non-PC x86 things
(embedded systems).  In such cases, I/O trapping is essential in order
to plug in the software emulation for the emulated peripherals. 

Finally, if a non-trusted task can randomly access the aliases of 
10-bit-decoded addresses, you can have problems.  I peered at an older
version of the DOS emulator, and was a little concerned about such issues.

If it would be helpful, I could probably write up some more detailed
suggestions and post them to you privately.

Best regards,
Terry Moore
Databook Inc.