Windows 3.0 bombs on startup under VP/ix 1.1 (ISC 2.2)

[Marc Unangst]

shwake at raysnec.UUCP (Ray Shwake) writes:
> 	It's been my understanding that earlier versions of Windows were
> runnable under VP/ix. Though I'm running a little low on memory (4 MB) on
> this platform, decided to fire it up from a mounted filesystem (/dos).
> Upon startup, confronted the error:
> 
> 		General protection fault, cannot emulate instruction

Well, I haven't actually done any testing or anything, but I'd bet the
problem goes something like this:

Unix is an OS that runs in the 386's protected mode.  Windows 3.0,
usually, is an OS that runs in the 386's protected mode.  When you
start up a VP/ix session under Unix, you're creating a virtual 8086,
not a virtual 80386.  So, when Windows 3.0 tries to execute its 386
instructions, it fails the same way it would if you tried to run it on
a regular XT clone -- with an "illegal instruction" error.  (Except,
on the XT, you'd get a nice system crash.  On the 80386, you get a
core dump.)

The solution to this is to run Windows in "real mode".  There should
be a command-line switch for this, but I don't have Windows 3.0 so I
can't check.  Either that, or wait for the 80686, which will hopefully
have a virtual 80386 mode.

--
Marc Unangst               |
mju at mudos.ann-arbor.mi.us  | "Bus error: passengers dumped"
...!umich!leebai!mudos!mju |