Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!wuarchive!mit-eddie!bloom-beacon!eru!luth!sunic!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: <884@ztivax.UUCP>
Date: 20 Dec 89 09:40:25 GMT
References: <26317@sequent.UUCP> <901@crash.cts.com> <832@ocsmd.ocs.com> <83311@linus.UUCP> <868@ztivax.UUCP>
Reply-To: yip@ztivax.UUCP (Dr Yeung-Cho Ip)
Organization: Siemens AG in Munich, W-Germany
Lines: 32


Sorry for posting this here, but I couldn't reach Bruce through net mail.

Hello Bruce,

in your letter you wrote:

> Where does the controller leave the parameters? I would like to stop Minix
> overwriting them for version 1.5.
>
> I suspect they are being put in the interrupt table (below 0x00400) since
> Minix doesn't touch (much of) 0x400-0x5FF and everything above there is
> touched by DOS. 

You're right. The quick and dirty changes I mentioned in my message are nearly
one and a half year old. Yesterday, I had a closer look on the way our ADAPTEC
controller works, and I found out that it writes the disk parameters to the
locations 384 (decimal) upwards.

In addition, I altered the at_wini.c so that it now correctly handels this case
Since I don't know whether all ADAPTEC and Western Digital
controllers use the same locations, my approach differs from your
suggestion. I altered the constant VECTOR_BYTES so that the kernel (main)
saves the disk parameters to vec_table prior to overwriting them. The
at_wini then reads the parameters from this table, provided the pointer at 0x41
points to the low ram lokations.

I will post this new at_wini.c in a few minutes.

Michael

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