FreeBSD install disables linux partitions and system

[oliver-forward at charter.net]

Hello,

I have (had?) a machine with two drives with two major partions on each. One on the first drive was used for Mandriva linux, one on the second used for its /home folder. I wanted to try FreeBSD because I could not get my Plextor SCSI CD-R/W drive to operate under Mandriva 2006. I copied /home to the first partition, that being as much of a back-up as I could do. Then I followed the instructions in the FreeBSD handbook for a dual-boot system. This involves putting the FreeBSD bootloader on both drives.

Once I had FreeBSD 6.0 and KDE up and running, I recompiled my kernel with extfs functionality and tried to mount my Linux drives. This failed:

bsd# mount -t ext2fs /dev/ad2s2 /linux-tmp
mount_ext2fs: /dev/ad2s2: Invalid argument

This is what I am getting now. I also got "you must have read-write privileges or be root," but for some reason that is gone. ad2s2 is what my old /home partition showed up as in sysinstall.

I installed and tried e2fsck, but no use:

bsd# /usr/local/sbin/e2fsck /dev/ad2s2
e2fsck 1.38 (30-Jun-2005)
Couldn't find ext2 superblock, trying backup blocks...
/usr/local/sbin/e2fsck: Bad magic number in super-block while trying to open /dev/ad2s2

The superblock could not be read or does not describe a correct ext2
filesystem.  If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>

I tried a few other numbers, but to no avail.

What makes this bad for me is that the FreeBSD bootloader will not boot Mandriva. Attempting to choose anything but FreeBSD rings the system bell and does nothing else. The Mandriva rescue disk is unable to restore its original bootloader, or read from the drive with the FreeBSD partition on it, or repairthe system without wiping the disk. I no have no access to my data at all. 

I don't think it is meant to function this way, but I read the install part of the handbook three times and cycled round in sysinstall at least as many times to make sure I had it right. Any help would be appreciated. Thank you.

Oliver