*BSD News Article 7494


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Newsgroups: comp.unix.bsd
From: jaggy@purplet.demon.co.uk (Mike Jagdis)
Path: sserve!manuel.anu.edu.au!munnari.oz.au!sgiblab!zaphod.mps.ohio-state.edu!cs.utexas.edu!news.uta.edu!hermes.chpc.utexas.edu!news.utdallas.edu!corpgate!bnrgate!bnr.co.uk!pipex!demon!purplet!jaggy
Subject: Drive geometries
Organization: FidoNet node 2:252/305 - The Purple Tentacle, Reading
Date: Wed, 4 Nov 1992 22:16:08 +0000
Message-ID: <44.2AF5C5E8@purplet.demon.co.uk>
Sender: usenet@gate.demon.co.uk
Lines: 38

Well, I decided to have yet another bash at getting 386bsd to live in a 
partition on my HD and share it with Linux...

  Firstly the drive is a Maxtor LXT535A IDE. The postage stamp, er, manual I 
got with the drive gives several recommendations for CMOS parameters, the 
two that give the highest capacity being 1024 cylinders, 16 heads, 63 
sectors and 1036 cylinders, 16 heads, 63 sectors. Another piece of paper I 
got with another Maxtor drive give physical specifications for several 
drives among them the LXT535A which it says has 11 data heads and 1560 
cylinders.

  Hmmm... The 1024 and 1036 look like DOS-isms. I tried the physical 
parameters. No joy. Classic failure - unable to read disklabel after the 
kernel has loaded.

  No problem. Run Frank's ide_conf. The drive seems to be claiming to be 
1024x16x63. Hey! I *know* it's bigger than that! The manual gives 1036 as a 
possible config!

  Tried it. No joy. Install hangs before it even asks me if I want to 
install in the 386bsd partition. I can ^C out though, so maybe this is 
something other the device driver barfing?

  Just to check I set the parameters to 1560x11x63 and used Linux to build 
filesystems all over - no problems, it seems valid. (An extra cylinder 
killed it).

  Moral? Well, just because a drive has a default geometry doesn't mean it 
should be automatically prefered. It seems that even if I installed 386bsd 
on the whole drive I would be better off running it with a translated 
geometry since it lies about the number of heads it has by default!?!


                                Mike

(BTW Anyone any clues as to why install hangs now? It worked with my 
initial attempts when using the geometry from the physcial spec. but not now 
with the default geometry.)