From: H. Peter Anvin N9ITP (hpa@casbah.acns.nwu.edu)
Date: 03/16/92


From: hpa@casbah.acns.nwu.edu (H. Peter Anvin N9ITP)
Subject: Re: DOS emulator  for Linux?
Date: Mon, 16 Mar 1992 21:37:25 GMT

In article <097hpd=@lynx.unm.edu> of alt.os.linux,
  techs@triton.unm.edu (Erik Fichtner) writes:
> This probably isn't a great question since Linux is a hackers OS and Messy-dog
> isn't, but are we ever likely to see a DOS emulator of some form running under
> Linux? The machine i'm playing with linux on in the wee hours of the night
> also runs a BBS system under MS-DOS by day. None of my other machines run
> MS-DOS, emulated or otherwise. I think Linux is an *excellent* hack..
> great work, Linus... keep up the good work... now if it only had a DOS
> emulator, I wouldn't be forced to play with it in the middle of the night.

HOW TO MAKE A SIMPLE DOS EMULATOR
=================================

Needed
======
1. A 386 or 486 computer
2. A real OS
3. MS-DOS
4. A hard disk
5. Time

Put the 386/486 in virtual 8086 mode. Trap all interrupts and I/O port
accesses. Catch the general protection fault to simulate the action of the
hardware. Initialize the memory segment allocated to this virtual system
to be the same as of DOS at boot time. Force a boot from a DOS partition
on the hard disk. Let run. Puke.

        /hpa

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