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Date: Tue, 01 Apr 1997 11:02:01 +0300
From: Nadav Eiron <nadav@barcode.co.il>
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To: kkphang <phang@dgate.po.my>
CC: freebsd-questions@FreeBSD.org
Subject: Re: How to install 2.1.7 & 2.2 on the same hard disk
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kkphang wrote:
> 
> First I install 2.1.7R on partition 2 and then
> 2.2R on partition 3 later, everthing fine except
> that I can't go back to 2.1.7R anymore. :(
> 
> Here is the mount output on 2.2R
> 
> /dev/wd0a on / (local)
> /dev/wd0s4f on /usr (local)
> /dev/wd0s4e on /var (local)
> procfs on /proc (local)
> 
> Look like wd0a is point to /dev/wd0s4a now??
> Any idea how to make it work, thank in advance.
> 
   [fdisk output sniped]

You can't (AFAIK) boot two versions of FreeBSD from the same disk. There
can be only *one* bootable FreeBSD slice on a disk. This is clearly
reflected by the slice not being specified for the root partition (i.e.
it is written as just wd0a and not wd0s4a). Perhaps some fancy software
can hide the partition you don't need, but the best would be to get
another disk for this. Note that it's just the root partition that
matters, so you can take a second disk with just a little room left on
it and put just the root partition on it.

Sorry,
Nadav