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Re: disklabel writing behavior?
from "Julian Fagir" <listensammler%q827es.in-berlin.de@localhost>
> I wonder nobody else answered, so I'll do. This is one of the usual topics
> you are always absolutely sure about, but if someone asks, you have to admit
> that you never looked at the source code and always only 'had that
> behaviour', but don't know for sure about the general case.
> So, I'll assume that the behaviour I always assumed and experienced on my
> machines is the general case (as it is the only one that would make sense).
> > How does NetBSD disklabel behave when writing a disklabel when the disk
> > involved has multiple slices/BIOS partitions? Does the disklabel go only
> > on the NetBSD partition, or can it intrude on another partition where
> > another OS, like FreeBSD, Linux or DOS is installed?
> No, the disklabel is only written onto the slice you chose to.
Thanks for your response. I looked at the source code but not the same
section. I was trying to find the one-character commands to use inside
This is my present hard-disk partitioning, output of "fdisk -lu /dev/hda" run
Disk /dev/hda: 41.1 GB, 41174138880 bytes
16 heads, 63 sectors/track, 79780 cylinders, total 80418240 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0xdcc1dcc1
Device Boot Start End Blocks Id System
/dev/hda1 63 16964639 8482288+ a9 NetBSD
/dev/hda2 16964640 17992799 514080 82 Linux swap
/dev/hda3 17992800 54701324 18354262+ 83 Linux
Partition 3 does not end on cylinder boundary.
/dev/hda4 * 54701325 80405324 12852000 a5 FreeBSD
Partition 4 does not end on cylinder boundary.
I remember I had the FreeBSD disklabel (bsdlabel ad0s4) look just like the
NetBSD disklabel after I had built and installed a lot of the FreeBSD ports, so
I didn't want to lose the FreeBSD installation. But I recovered by running
bsdlabel with a saved copy of the FreeBSD disklabel. Last version of NetBSD I
had installed was 5.0.2 patch/update. This does not happen when updating
NetBSD from CD as opposed to a fresh install with disklabel and newfs. I
recently read something about this happening on
freebsd-questions%freebsd.org@localhost emailing list. Now I have NetBSD
5.1_RC3 on the NetBSD partition.
I think something like this might have happened earlier when I had FreeBSD 7.2
installed but had not added any packages/ports and couldn't boot or read that
partition. By the time I got to fixing it, FreeBSD 8.0 was released, so I
installed that fresh. It was not until I had the problem on FreeBSD 8.0
installation that I realized what might have happened.
I can check the source code for disklabel since I downloaded and installed the
NetBSD source: 5.1_RC3 on this hard disk and 4.0.1 on a 4 GB USB stick. I can
look for what happens when a disklabel is written.
Anyway, I repeat that it's always a good idea to keep a copy of the partition
table and disklabels on a separate msdos-formatted disk, can be a floppy or USB
stick. One can mess up a disklabel from the installation program sysinst
(NetBSD) or sysinstall (FreeBSD): so many ways to get confused in FreeBSD
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