i386/121124: FreeBSD 6.3 installation deletes MBR partition

[Dan Strick]

> From linimon at FreeBSD.org Thu Feb 28 16:58:12 2008
> To: dan_strick at sbcglobal.net, linimon at FreeBSD.org, freebsd-i386 at FreeBSD.org
> Subject: Re: i386/121124: FreeBSD 6.3 installation deletes MBR partition
>
> Synopsis: FreeBSD 6.3 installation deletes MBR partition
>
> State-Changed-From-To: open->analyzed
> State-Changed-By: linimon
> State-Changed-When: Thu Feb 28 21:42:44 UTC 2008
> State-Changed-Why: 
> It sounds as though the problem is a lack of error-checking robustness.
>
> http://www.freebsd.org/cgi/query-pr.cgi?pr=121124
>

My best guess is that sysinstall checked the MBR partition table for
sanity and decided to "fix" an overlap by arbitrarily deleting one of
the overlapping partitions.  That was the wrong thing to do since none
of the overlapping partitions was involved in the FreeBSD installation.
What other operating systems do with their slices is their business.
Generating a warning message was plausible.  Making gratuitous changes
to the partition table was not.

I believe it is common sense for an MBR partition table editor to change
only those partitions that it is explicitly told to modify.  Sysinstall
was not told to modify either of the overlapping slices and should have
left them strictly alone.

Dan Strick