*BSD News Article 34686


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Newsgroups: comp.os.386bsd.misc
Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!msuinfo!agate!howland.reston.ans.net!pipex!bt!uknet!cf-cm!isl-gate.elsy.cf.ac.uk!paul
From: paul@isl-gate.elsy.cf.ac.uk (Paul)
Subject: Re: FreeBSD 1.1.5.1 disk geometry problem...Help!
Message-ID: <1994Aug20.153924.21234@cm.cf.ac.uk>
Sender: paul@isl-gate.elsy.cf.ac.uk (Paul)
Nntp-Posting-Host: isl-gate.elsy.cf.ac.uk
Organization: ELSYM, University of Wales, College of Cardiff, UK.
References: <32rl4m$397@cville-srv.wam.umd.edu>
Date: Sat, 20 Aug 1994 15:39:22 +0000
Lines: 40

In article <32rl4m$397@cville-srv.wam.umd.edu>,
Garth H. Brantley <garthb@wam.umd.edu> wrote:
>    I am tryin to install FreeBSD 1.1.5.1 for the first time.  I have
>a P66 with 8mb and 810mb IDE drive with a PCI contoller.  My hard drive
>has 1572 cyln, 16 heads, 63 secotrs/track but the bios translates this to
>786 cyln, 32 heads, 63 secotrs.  This is neccesary for DOS to support
>partitions that go past cyln 1024.  When I set FreeBSD to 1572, 16, 63 
>the computer hangs at boot saying "Missing Operating System".  I found
>this in the FAQ and it suggested that I use the same disk geometry that
>DOS was using so I reinstalled FreeBSD and set it to 786, 32, 63.  This 
>seems to work at first, but the error message "32 heads not supported, 
>resetting to 16 heads" keeps apearing and the system wont work.
>    If Anybody else out there has set up FreeBSD with a >1024 cyln IDE 
>hard drive I would appreciate it if you could help me.  Thank You.

This is becoming a FAQ.

Assuming you don't want more than 512Mb in your DOS partition do the
following.

* Disable the LBA in the BIOS. DOS will just see a smaller disk but that
  doesn't matter because FreeBSD will use the space that DOS can't see.
* Re-partition the hard disk with the partition on the lower cyliders
  for DOS and a second empty partition ready for FreeBSD.
* Install DOS in the first partition.
* Install FreeBSD, it should detect the DOS partition and install itself
  into the free partition. It will get the correct disk geometry for
  itself from the drive since you won't be using any translation now.


LBA is only needed if you need to access cylinders above 1024 from within
DOS. If your DOS partition lies below the 1024 cylinder limit then you
can and should disable it to allow FreeBSD to get the real disk geometry.
The wd driver in FreeBSD will reject a geometry with more than 16 heads
because the IDE spec (I think) states that 16 is the limit. It doesn't
know about the new LBA BIOS options.
-- 
  Paul Richards, FreeBSD core team member.
  Intelligent Systems Laboratory, ELSYM ,University of Wales, College Cardiff
  Internet: paul@isl.cf.ac.uk,  JANET(UK): RICHARDSDP@CARDIFF.AC.UK