Subject: restoring the boot selector; repairing the disk label
To: None <port-i386@netbsd.org>
From: Steve Bellovin <smb@research.att.com>
List: port-i386
Date: 03/31/2001 00:16:30
I have NetBSD 1.5R running on a machine. However, I made the mistake
of installing the Evil OS from Redmond in another partition -- which
overwrote the boot selector, so that it only boots you-know-what. How
do I restore the boot selector? I've tried 'fdisk -B' and 'fdisk -i',
to no avail. (Both of those were done after booting from the cd, using
'boot wd0a:netbsd', and running the commands in single-user with all
file systems mounted read-only.)
While I'm at it -- what changes should I make to my disk label to be
able to mount the Windows partition? Here's what I know of the disk:
# fdisk; disklabel wd0
NetBSD disklabel disk geometry:
cylinders: 16383 heads: 16 sectors/track: 63 (1008 sectors/cylinder)
BIOS disk geometry:
cylinders: 1024 heads: 255 sectors/track: 63 (16065 sectors/cylinder)
Partition table:
0: sysid 12 (Primary DOS with 32 bit FAT - LBA)
start 1024, size 25175792 (12292 MB), flag 0x80
beg: cylinder 0, head 16, sector 17
end: cylinder 1023, head 254, sector 63
1: sysid 169 (NetBSD)
start 25176816, size 124959744 (61015 MB), flag 0x0
beg: cylinder 1023, head 254, sector 63
end: cylinder 1023, head 254, sector 63
2: <UNUSED>
3: <UNUSED>
# /dev/rwd0d:
type: unknown
disk: NetBSD
label:
flags:
bytes/sector: 512
sectors/track: 63
tracks/cylinder: 16
sectors/cylinder: 1008
cylinders: 16383
total sectors: 150136560
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0 # microseconds
track-to-track seek: 0 # microseconds
drivedata: 0
8 partitions:
# size offset fstype [fsize bsize cpg/sgs]
a: 1091664 25176816 4.2BSD 1024 8192 16 # (Cyl. 24977 - 26059)
b: 2098656 26268480 swap # (Cyl. 26060 - 28141)
c: 124959744 25176816 unused 0 0 # (Cyl. 24977 - 148944)
d: 150136560 0 unused 0 0 # (Cyl. 0 - 148944)
e: 121769424 28367136 4.2BSD 1024 8192 16 # (Cyl. 28142 - 148944)
--Steve Bellovin, http://www.research.att.com/~smb