Path: utzoo!attcan!uunet!lll-winken!ames!oliveb!sun!sally!plocher
From: plocher%sally@Sun.COM (John Plocher)
Newsgroups: comp.unix.microport
Subject: Re: Microport device drivers use BIOS???!?
Message-ID: <99265@sun.Eng.Sun.COM>
Date: 16 Apr 89 09:17:18 GMT
References: <1346@igloo.Scum.COM>
Sender: news@sun.Eng.Sun.COM
Lines: 22

From article <1346@igloo.Scum.COM>, by jjw@igloo.Scum.COM (John Welch):
> 	Some time ago, Igloo ran on an old 286 with Phoenix BIOS. Microport
> 	Now igloo is on another machine, this time with AMI BIOS. Same trouble
> 	My question is - I thought that BIOS was real-mode code, and not
> the BIOS ONLY was changed??? Seems to me that Microport, in some way or
> another, is running BIOS to do disk i/o. They could be running it under
> protected mode, or they could be dropping back into real mode to do this.

BullShit!

The ONLY way that the BIOS interfaces to Microport Unix is thru whatever the
BIOS does at POST time.  After the big switch into protected mode (about
50 lines of code after you see the boot(system5): prompt) the BIOS is never
used by unix.  I know, I worked on the driver.

DosMerge WHEN RUNNING DOS allows the DOS task full access to the BIOS
(after all, the machine switches back to REAL mode to run the DOS task)
This is a DOS only thing, though.  Whenever an interrupt comes in, the
machine switches into protected mode, handles the interrupt, and then
switches back to real mode.

   -John Plocher