Date: Wed, 11 Oct 1995 13:42:43 -0700 (PDT) From: Julian Elischer <julian@ref.tfs.com> To: adhir@iagi.net (Alok K. Dhir) Cc: questions@freebsd.org, stable@freebsd.org Subject: Re: Boot off of sd0 Message-ID: <199510112042.NAA03105@ref.tfs.com> In-Reply-To: <Pine.BSF.3.91.951010185244.5714A-100000@bigdipper.iagi.net> from "Alok K. Dhir" at Oct 10, 95 07:01:49 pm
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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 > loss. > > 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 > -B"? > > 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 If you want to make this work, then change (by hand) the beg: figures to: cyl 0: sector 47: head 0: use fdisk -u sd0 for this and change NO OTHER fields.. (use the defaults given as long as they) agree with what you gave here.. ALTERNATIVELY: set the BIOS parameters used in fdisk to be 64 heads, 32 sectors 4000 tracks and allow it to recalculate the beg/end figures automatically MAKE SURE YOU USE THE SAME start 46, size 8385984 (4094 Meg), flag 80 figures you used before.. (or you'll have to re-install the data..) it probably would have been a better thing to start at 64 and set the figures to match the BIOS but you'll be ok with these.. > The data for partition 1 is: > <UNUSED> > The data for partition 2 is: > <UNUSED> > The data for partition 3 is: > <UNUSED> > > And here's the output from "disklabel sd0": > > # /dev/rsd0c: > type: SCSI > disk: sd0s1 > label: > flags: > 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... > > Thanks! > > Alok K. Dhir > Internet Access Group, Inc. > adhir@iagi.net > (301) 652-0484 Fax: (301) 652-0649 > http://www.iagi.net > >
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