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Date:      Tue, 10 Oct 1995 19:01:49 -0400 (EDT)
From:      "Alok K. Dhir" <>
Subject:   Boot off of sd0
Message-ID:  <>

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Hey all - we recently suffered the death of a 2 gig Quantum Empire due to 
over heating (the server room AC vent was off and poof went the disk).  
In any case, I've reinstalled and restored most of our data off of 
backups and fortunately we're back to where we were without too much 

The problem I'm having is that I can't get the system (running 
951005-snap of 2.1-stable) to boot off of sd0.  I think I may have 
screwed something up during the disklabel portion of the custom install.  
If I boot without a floppy in the drive, I get a 
"Missing Operating System" message from the BIOS (I assume its from the 
BIOS, anyway).  If I boot off of a boot floppy and enter "sd(0,a)/kernel" 
at the boot prompt, everything comes up beautifully.

I have used "fdisk -a" to set the first partition (0) active (the entire 
disk, a Seagate 4 gig Hawk, is dedicated to FreeBSD) and have run 
"disklabel -B sd0".  The server's up and running (production) as we 
speak, so I can't test to see if what I did worked without interrupting 
my users.  I just want to make sure that what I did is correct before I 
reboot the system tonight around 2am (I won't be near the machine when I 
boot it so if what I did is NOT correct, I'll have to drive to the office 
in my jammies to boot it).

Is there anything else I need to do to get the system to boot off of 
sd(0,a)/kernel other than setting the active partition to 0 and "disklabel 

Here's the output from fdisk:

******* Working on device /dev/rsd0 *******
parameters extracted from in-core disklabel are:
cylinders=9595 heads=19 sectors/track=46 (874 blks/cyl)

 Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=9595 heads=19 sectors/track=46 (874 blks/cyl)

Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 0 is:
sysid 165,(FreeBSD/NetBSD/386BSD)
    start 46, size 8385984 (4094 Meg), flag 80
        beg: cyl 0/ sector 1/ head 1;
        end: cyl 1023/ sector 46/ head 18
The data for partition 1 is:
The data for partition 2 is:
The data for partition 3 is:

And here's the output from "disklabel sd0":

# /dev/rsd0c:
type: SCSI
disk: sd0s1
bytes/sector: 512
sectors/track: 46
tracks/cylinder: 19
sectors/cylinder: 874
cylinders: 9594
sectors/unit: 8385984
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0           # milliseconds
track-to-track seek: 0  # milliseconds
drivedata: 0 

8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  a:   204800        0    4.2BSD        0     0     0   # (Cyl.    0 - 234*)
  b:   262144   204800      swap                        # (Cyl.  234*- 534*)
  c:  8385984        0    unused        0     0         # (Cyl.    0 - 9594*)
  e:  4096000   466944    4.2BSD        0     0     0   # (Cyl.  534*- 5220*)
  f:  3823040  4562944    4.2BSD        0     0     0   # (Cyl. 5220*- 9594*)

Please advise...


Alok K. Dhir
Internet Access Group, Inc.
(301) 652-0484  Fax: (301) 652-0649

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