Date: Thu, 4 Jan 1996 10:53:05 -0800 (PST) From: "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com> To: peter@jhome.DIALix.COM (Peter Wemm) Cc: current@freebsd.org Subject: Re: Odd question.. ;-) Message-ID: <199601041853.KAA29761@GndRsh.aac.dev.com> In-Reply-To: <Pine.BSF.3.91.960104213427.476A-100000@jhome.DIALix.COM> from "Peter Wemm" at Jan 4, 96 09:43:52 pm
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>
> Hi all..
>
> I have a strange question.. (even stranger since it's from somebody who
> should know.. :-)
>
> How do I update the boot code to -current? :-)
1) fdisk sd0 | lpr #Hardcopy so you can read it if it gets
#trashed
2) disklabel sd0 | lpr #Ditto
3) disklabel -B sd0
4) fdisk sd0 #Make sure it matches 1) above.
>
> Last time I messed with disklabel and /usr/mdec, I ended up trashing my
> system beyond repair.. I've not looked again in something like 12 months.
Your disk is probably partitioned so that the offset of the BSD slice
starts at sector 0 of the disk, this causes the boot1 code to overlay
the MBR when you do a disklabel -B, which causes your MBR to revert to the
compiled in one.
I have seen other replies saying that they have had no problem whatsoever
with disklabel -B, and that will be true so long as the offset of your BSD
slice is >0 sector.
For example:
******* Working on device /dev/rsd0 *******
parameters extracted from in-core disklabel are:
cylinders=511 heads=64 sectors/track=32 (2048 blks/cyl)
parameters to be used for BIOS calculations are:
cylinders=511 heads=64 sectors/track=32 (2048 blks/cyl)
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 0 is:
<UNUSED>
The data for partition 1 is:
<UNUSED>
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
sysid 165,(FreeBSD/NetBSD/386BSD)
start 0, size 1046528 (511 Meg), flag 80
beg: cyl 0/ sector 1/ head 0;
end: cyl 510/ sector 32/ head 63
SkyRsh#
SkyRsh# disklabel -B sd0
SkyRsh# fdisk sd0
******* Working on device /dev/rsd0 *******
parameters extracted from in-core disklabel are:
cylinders=511 heads=64 sectors/track=32 (2048 blks/cyl)
parameters to be used for BIOS calculations are:
cylinders=511 heads=64 sectors/track=32 (2048 blks/cyl)
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 0 is:
<UNUSED>
The data for partition 1 is:
<UNUSED>
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
sysid 165,(FreeBSD/NetBSD/386BSD)
start 0, size 50000 (24 Meg), flag 80
beg: cyl 0/ sector 1/ head 0;
end: cyl 1023/ sector 63/ head 255
SkyRsh#
Boom... there goes my partition table :-(.
> Basically, I want to install a new /usr/mdec/boot2, because this system
> has a version 2.0.5 boot2 that has the missing LF during boot.. :-)
> (real crisis, eh? :-)
>
> So, what do I do? disklabel -B sd0 ? I think last time I did that, I
> lost the fdisk tables... but I dont really remember...
--
Rod Grimes rgrimes@gndrsh.aac.dev.com
Accurate Automation Company Reliable computers for FreeBSD
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