*BSD News Article 9765


Return to BSD News archive

Received: by minnie.vk1xwt.ampr.org with NNTP
	id AA6463 ; Sat, 09 Jan 93 17:14:46 EST
Newsgroups: comp.unix.bsd
Path: sserve!manuel.anu.edu.au!munnari.oz.au!uunet!zaphod.mps.ohio-state.edu!malgudi.oar.net!hyperion!wright!corcoran
From: corcoran@valhalla.cs.wright.edu (Michael P. Corcoran)
Subject: SOLUTION to 386bsd problem of panic:can't mount /
Message-ID: <1993Jan12.051517.12955@cs.wright.edu>
Sender: corcoran@cs.wright.edu (Michael P. Corcoran)
Organization: Wright State University
Date: Tue, 12 Jan 1993 05:15:17 GMT
Lines: 35

The problem:
I posted a message a couple of days ago saying that I could not
get 386bsd to boot correctly because it kept failing with a message
panic: "can't mount root"
I found that the disk label was being corrupted whenever I rebooted.
 
The cause:
The disk controller was mapping the 1632 Cyls 8 heads into 1024 cyls 
16 heads to overcome the dos 1024 cyl limitation.  BSD was trying to 
use the "real" mapping while DOS was trying to use the translated 
mapping and they conflicted.  
(thanks to ejh@slustl.slu.edu for pointing it out!)

The solution: 
My solution was to simply tell the controller to use native 1 to 1 mapping.
This was an option in the ROM setup program in the controller run by
getting in through DOS debug and then -g=c800:5.
This causes DOS to think the entire disk is only about 200 Meg (out of 360)
but I don't care.  The dos partition only uses the first few sectors anyway.
BSD correctly sees that dos partition and reports the right number for
the amount of disk left (total - dos).

So I'm on my way to an endless wonderland in bsd, installing and maintaining
yet another OS on top of the 60 Sun and Dec workstations I already help
to maintain.

Now I have to install X and a billion patches.... <yawn> time for sleep.

Mike

-- 
_____________________________________________________________________________
 Michael P. Corcoran, Computer Systems Engineer (corcoran@cs.wright.edu)
 College of Engineering and Computer Science	FAX  :(513) 873-5009
 Wright State University, Dayton, Ohio.  	VOICE:(513) 873-5157