*BSD News Article 13012


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From: jdg00@ccc.amdahl.com (Josh Grosse)
Newsgroups: comp.os.386bsd.questions
Subject: SOLUTION FOR: "Ack!  Ick!  Ook!  Argh!"
Message-ID: <24Qp02sK3bXU01@JUTS.ccc.amdahl.com>
Date: 18 Mar 93 19:09:27 GMT
References: <fcpA02Mq3aKZ01@JUTS.ccc.amdahl.com> <1993Mar17.231431.11153@hemlock.cray.com>
Reply-To: jdg00@amail.amdahl.com (Josh Grosse)
Organization: Amdahl Corporation, Sunnyvale CA
Lines: 52

willie@willow38.cray.com (William Lewis) writes:

>I have the same problem with my second drive after reboots.  What I do to
>recover without losing the drive is a disklabel -e -r and just change the
>corrupted fields.  You might try this.
>
>Could someone let me know what's causing this? I've nearly got my system
>stable enough for my purposes, and this is the only major obstacle.

The root cause was my pc manufacturer using an AT "standard" disk geometry
instead of the disk manufacturer's recommendations to obtain a 127MB drive.

I received letters with suggestions overnight from Andrew Moore
(alm@netcom.com) and from Thomas Sandford (t.d.g.sandford@comp.brad.ac.uk)
who told me that I had the nefarious IDE-translation problem. Apparantly,
the problem only strikes when you try to partition a disk drive.  If you
use the entire disk for BSD, it doesn't care.

Thomas gave detailed procedures in his letter, suggesting:

   1) Backup up your other partitions
   2) Discover your actual disk geometry
   3) Use CMOS Type 48 or Type 49 to insert the "user" geometry in your CMOS.
   4) Fdisk, format, and restore your partitions
   5) Install TinyBSD.

Thomas recommended a program called "ideconf" which can report what the disk
thinks it really is.  I used my disk drive manufacturer and a telephone, as
I could not locate a copy of this software via Archie.  TinyBSD tells you
the disk-drive model number at boot-up, in the "wd0: " text.

My disk drive is actually an RLL technology drive that uses IDE because
the sectors per track changes across the face of the disk.  This is a
Seagate Technology ST9144A 127MB disk drive, which is a 2.5" 3 platter drive.
They use a changing form factor in order to pack 127MB into 7 ounces.

Seagate recommends using 980 cylinders, 15 heads, and 17 sectors, which
is a non-standard "user" configuration.  Texas Instruments, who put
the notebook together, used 735/10/34 respectively, as this is a standard
"type 37" disk configuration.

I changed my form factor to the recommended 980/15/17, and now TinyBSD works
fine!  It seems that Seagate reports their recommended geometry as "physical"
because the drive doesn't actually have a physical geometry to report.

My thanks to Thomas and Andrew for their help with my problem!

-- 
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Josh Grosse                                jdg00@amail.amdahl.com
Amdahl Corp.                               313-358-4440
Southfield, Michigan