From: samiam@netcom.com (Scott Moore) Subject: Re: dosemu and windows Date: Tue, 1 Jun 1993 06:57:21 GMT
There is one other way. The "real mode" windows could run under several
enviornments because it basically assumed an 8086+dos+vga interface. For
instance, the old windows prior to 3.0 would run under os/2 1.x.
The reason that running windows is such a problem is that it now uses 286/386
manipulations, essentially taking on os level operations that dos does not
provide.
Any os can get back the high ground by simply emulating at a higher level.
This is VM level technology. The emulator traps all 386/486 accesses as now,
but emulates them. For instance, the emulated CPU would have it's own page
tables, emulated disk, etc.
What this buys you is you don't care or deal with windows internals. You
simply increase the "fidelity" of the emulated CPU until the damm thing
works. And at the same time, you get compatibility with any following version
of windows, or any other OS for that matter !
The 386 is said to not be "completely self emulatable" meaning that there
are cases that you can't fully trap and emulate xyz bit fiddle. But those cases
are trivial, and if windows dosen't depend on them, it will work. I don't
know about the 486.
Responses ?
<sam>
-- Scott A. Moore [SAM] | This space for rent. samiam@netcom.com | Santa Cruz, CA USA | 408-423-1624 | ExaByte Corp. | "my opinions do not represent my company, etc." ========================================================================