Path: utzoo!attcan!uunet!husc6!bbn!apple!well!tneff
From: tneff@well.UUCP (Tom Neff)
Newsgroups: comp.unix.microport
Subject: Re: Microport device drivers use BIOS???!?
Summary: maybe it's the drive parameters
Message-ID: <11337@well.UUCP>
Date: 17 Apr 89 04:08:52 GMT
References: <1346@igloo.Scum.COM>
Reply-To: tneff@well.UUCP (Tom Neff)
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 20

In article <1346@igloo.Scum.COM> jjw@igloo.UUCP (John Welch) writes:
> [286 machine has floppy problems under DOS and uPort V/AT with some
>    BIOS's, not with others]
>	My question is - I thought that BIOS was real-mode code, and not
>re-entrant, and all of those bad things that scre UNIX up. If that's the
>case, what explains the problems going away for both DOS *and* UNIX if
>the BIOS ONLY was changed??? 

I would be surprised if V/AT were mode switching for floppy I/O, you
would think that would run like a pig. Maybe for the floppy they
don't care?  Still doubtful.

Another thought is that they might steal the disk drive parameters,
including spin-up times and such, from the BIOS at the beginning of
the world, and use them to drive their own protected mode code.  Then 
you might have floppy problems with some BIOS's even thought the 
driver code itself never changed.
-- 
Tom Neff                  tneff@well.UUCP
                       or tneff@dasys1.UUCP