Date: Tue, 26 Feb 2008 09:03:41 -0800 (PST) From: Dan Strick <dan_strick@sbcglobal.net> To: FreeBSD-gnats-submit@FreeBSD.org Subject: i386/121124: FreeBSD 6.3 installation deletes MBR partition Message-ID: <200802261703.m1QH3fha001355@mist.nodomain> Resent-Message-ID: <200802261740.m1QHe1js017197@freefall.freebsd.org>
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>Number: 121124
>Category: i386
>Synopsis: FreeBSD 6.3 installation deletes MBR partition
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: freebsd-i386
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Feb 26 17:40:00 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator: Dan Strick
>Release: FreeBSD 6.3-RELEASE i386
>Organization:
none
>Environment:
System: FreeBSD mist.nodomain 6.3-RELEASE FreeBSD 6.3-RELEASE #0: Sun Feb 24 23:23:03 PST 2008 root@mist.nodomain:/usr/src/sys/i386/compile/MIST i386
>Description:
This was the MBR partition table for disk ad0 before I booted the
release 6.3 installation cd disk 1:
The data for partition 1 is:
sysid 11 (0x0b),(DOS or Windows 95 with 32 bit FAT)
start 63, size 8209152 (4008 Meg), flag 0
beg: cyl 0/ head 1/ sector 1;
end: cyl 510/ head 254/ sector 63
The data for partition 2 is:
sysid 99 (0x63),(System V/386 (such as ISC UNIX), GNU HURD or Mach)
start 8209214, size 1 (0 Meg), flag 0
beg: cyl 510/ head 254/ sector 63;
end: cyl 510/ head 254/ sector 63
The data for partition 3 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
start 8209215, size 8225280 (4016 Meg), flag 80 (active)
beg: cyl 511/ head 0/ sector 1;
end: cyl 1022/ head 254/ sector 63
The data for partition 4 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
start 16434495, size 143637165 (70135 Meg), flag 0
beg: cyl 1023/ head 0/ sector 1;
end: cyl 1023/ head 254/ sector 63
When I selected disk ad0 under the sysinstall partition menu it popped up
this warning message:
Disk slicing warning:
chunk 'ad0s2' [8209214..8209214] does not start on a track boundary
and showed this information when it entered the FDISK partition editor:
Disk name: ad0 FDISK Partition Editor
DISK Geometry: 9964 cyls/255 heads/63 sectors = 160071660 sectors (78159MB)
Offset Size(ST) End Name PType Desc Subtype Flags
0 8209214 8209213 - 12 unused 0
8209214 1 8209214 ad0s2 4 unknown 99
8209215 8225280 16434494 ad0s3 8 freebsd 165
16434495 143637165 160071659 ad0s4 8 freebsd 165
160071660 12755 160084414 - 12 unused 0
I exited the partition editor without changing any partitions but I did
request installation of the usual FreeBSD boot manager (menu option BootMgr)
in the next menu.
After the installation was over I discovered that the first partition,
Windows XP, was now <UNUSED>. The other partitions were unmodified.
>How-To-Repeat:
Create a similar MBR partition table on some disk, run sysinstall
and select that disk under the
3 Partition Allocate disk space for FreeBSD
menu item in the "Choose Custom Installation Options" menu.
This also works if you run sysinstall from inside FreeBSD.
>Fix:
Work around: manually edit the MBR partition table with fdisk
from FreeBSD after the installation is complete. Of course we
saved a backup copy of the MBR before we began the FreeBSD
installion. Doesn't everybody? :-)
I used to think that only MS Windows installations callously
destroyed competing OS partions. Now FreeBSD joins the club.
:-)
>Release-Note:
>Audit-Trail:
>Unformatted:
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