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Date:      Sun, 22 Sep 1996 19:30:33 -0400 (EDT)
From:      rhh@ct.picker.com (Randall Hopper)
To:        karpen@ocean.campus.luth.se (Mikael Karpberg)
Cc:        hackers@freebsd.org
Subject:   Boot manager problems (was Re: fdisk changes, anyone?)
Message-ID:  <199609222330.TAA00676@elmer.ct.picker.com>
In-Reply-To: <199609221638.SAA02381@ocean.campus.luth.se> from "Mikael Karpberg" at Sep 22, 96 06:38:29 pm

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Mikael Karpberg:
 |Umm... I got myself a Medalist 2GB HDD and installed FreeBSD over FTP, and
 |everything worked just fine. Althought I choose "Entire disk" and told it
 |to make it a "real partition", I installed booteasy, just because. :-)
 ...
 |etc... F5 would make it go to the second disk and fail boot, but that was
 |expected. I tried a complete reinstall with different things, and setting
 |the bios setting for the disk to different things. No such luck.
 |Finally, I got a tip from a friend, and booted a little win95-dos floppy
 |and started dos fdisk. Delete nondos partition. Create primary dos
 |partition. Reboot. Format c:. Reboot from FBSD floppy. Install everything
 |once more, this time first deleting the dos partition and then doing just
 |a *C*reate and hitting return to get biggest possible partition. Install
 |finnishes, I reboot, and viola! Works like a charm.

     I'm not sure I completely got what you did in both cases, but it
sounds a lot like what I went through with my first installation.  I was/am
using OS/BS v2.0b8 as a boot manager, and it installs itself on the first
few sectors of the hard drive (Booteasy just uses the first sector, I
believe).  Installed FreeBSD in its own slice which started at the second
sector of the hard disk, and then installed OS/BS which wiped out the front
of the FreeBSD partition (which I figured out later of course).

     I believe a similar scenario can occur if you tell FreeBSD to take up
the whole disk as you did (i.e. don't use slices and not install within a
slice), in which case FreeBSD should start at sector 1 of your hard drive.
If you then install a boot manager, that overwrites at least sector 1 of
the drive and maybe a few more after that, depending on the boot manager.
This should effectively toast the front of your FreeBSD file system.

     One solution, which I believe is what you ended up with, is to fdisk
with DOS, and put FreeBSD in a slice.  DOS always leaves the first head
(typically the first 63 sectors, on a respectable-size hard drive) free
except for sector 1 which of course is the MBR, so all boot managers that
install there should work fine, without stomping on your FreeBSD and other
file systems.  Another alternative is to fdisk with FreeBSD, still using
slices, but make sure not to start the first partition before sector 64 (so
you can use any boot manager).

     By the way, you might find:

     http://www.freebsd.org/tutorials/multios/multios.html

useful.  It gives some more details, assuming this was your problem.

Randall Hopper
rhh@ct.picker.com



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