*BSD News Article 30716


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From: brian@awfulhak.demon.co.uk (Brian Somers)
Newsgroups: comp.os.386bsd.misc
Subject: Re: BSD/386+OS/2 boot manager
Date: 18 May 94 22:32:00
Organization: Coverform Ltd.
Lines: 32
Distribution: world
Message-ID: <BRIAN.94May18223200@awfulhak.demon.co.uk>
References: <2qgife$8p3@ndlc.occ.uky.edu> <2qig0n$8j5@news.kth.se>
NNTP-Posting-Host: awfulhak.demon.co.uk
In-reply-to: d88-jwn@damned.nada.kth.se's message of 8 May 1994 10:47:51 GMT

OS/BS replaces the first sector (except for the partition table) on your
boot disk.  The latest OS/BS also grabs a few more sectors (the first 32
are not normally used).

The BIOS identifies whether the disk is bootable by looking at this first
block (is it the jump statement at the start that it uses ?).  If you're
getting a 'no operating system' message, you probably need to either
reload OS/BS, or re-write block zero.  To re-write block zero, run

    fdisk /mbr

although this doesn't seem to be documented anywhere - at least not in my
dos manual.

If you can boot from floppy and access your hard disks OS-2/DOS/FreeBSD
partitions, this means that your partition table is still intact and both
methods should work (I'd recommend OS/BS).

If your partition table is intact, but you havn't got FreeBSD access, try
creating a DOS partition that totals the required FreeBSD size and using
a disk editor to change the system ID to A5h.  Then re-install FreeBSD.

Incidently, wouldn't it be nice to have new system IDs for NetBSD and
FreeBSD ?  This way, each OS could distinguish itself from the others,
and programs such as disklabel could be made capable of mucking around
with these primary partitions.

Brian.
--
Brian <brian@awfulhak.demon.co.uk>

Don't _EVER_ lose your sense of humour....