Path: utzoo!utgpu!water!watmath!clyde!rutgers!ames!amdcad!sun!pitstop!sundc!seismo!uunet!mcvax!botter!ast
From: ast@cs.vu.nl (Andy Tanenbaum)
Newsgroups: comp.os.minix
Subject: Re: Question about Minix port
Message-ID: <1838@botter.cs.vu.nl>
Date: 28 Jan 88 13:31:00 GMT
References: <1059@louie.udel.EDU>
Reply-To: ast@cs.vu.nl (Andy Tanenbaum)
Organization: VU Informatica, Amsterdam
Lines: 13

In article <1059@louie.udel.EDU> HELMER%SDNET.BITNET@cunyvm.cuny.edu (Guy Helmer) writes:
>Anyone care to comment on how Minix runs if drivers (floppy, tty, hard
>disk) are modified to use synchronous ROM calls, such as exist on the
>IBM PC?  How much is performance degraded...

It will certainly cost something, but I don't think it will be even a factor
of two.  Still, the only way to find out is to do it.  It should be very hard.
Just replace floppy.c with a call to an assembly code routine to invoke the
BIOS.  Be careful about low core.  Some BIOS ROMs do funny things with
low core, and MINIX lives at 1536.  In theory, 1024 to 1535 is yours.
If you write the code, measure it and tell us.

Andy Tanenbaum