Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!mcsun!unido!ztivax!yip
From: yip@ztivax.UUCP (Dr Yeung-Cho Ip)
Newsgroups: comp.os.minix
Subject: Re: How to get hard disk parameters at boot time
Message-ID: <868@ztivax.UUCP>
Date: 18 Dec 89 08:08:18 GMT
References: <26317@sequent.UUCP> <901@crash.cts.com> <832@ocsmd.ocs.com> <83311@linus.UUCP>
Reply-To: yip@ztivax.UUCP (Dr Yeung-Cho Ip)
Organization: Siemens AG in Munich, W-Germany
Lines: 24

In article <83311@linus.UUCP> gwr@linus.mitre.org writes:
>The best way to determine the hard disk geometry at boot time (on a
>PC/AT compatible) is to examine the BIOS hard disk parameter tables.
>

The "init_params" routine in the original at_wini.c does exactly that!

>First, many hard disk controllers include a controller BIOS with a
>boot-time routine that installs correct disk geometry parameters in
>some area of RAM and then points the parameter vectors at those new
>parameters.

The problem with our ADAPTEC controller board was, that MINIX overwrites
the  controller generated disk geometry parameters at boot up. When the
"init_params" routine in the at_wini driver tried to read the RAM location,
wich is referenced to by the vector 0x41, it allways got wrong disk parameters.
We fixed this quick and dirty by hardcoding the right parameters into our
at_wini.c .

Hope that helps

Michael Franzen

Michael Franzen, c/o yip@ztivax, Siemens AG, Munich