🚀 go-pugleaf

Philip Brown <phil+s3@bolthole.no-bots.com> wrote in message
news:slrn852n5a.pk6.phil+s3@shell3.ba.best.com...
> On Fri, 10 Dec 1999 14:14:27 +0100, hastenichtgesehen@gmx.de wrote:
> >> If a drive was labeled under Solaris 2.6 you will need to zap
> >> the drive label with dd.
> >[HOW] to zap a drive label with dd?
>
> dd if=/dev/zero count=1 of=/dev/rdsk/whtaerverp0
>
> NOTE THE "p0" at the end!!!
>
> This will kill the FDISK label.
> To destroy the solaris stuff.. Ummm...
> something like

You're confusing the SPARC and x86 platforms. The SPARC and x86
platforms have different >8GB problems, different label locations,
and different label sizes.

The original question was regarding the Ultra 5/10. Ultra 5/10s are
SPARC platforms. IDE (and SCSI) disk drives on S7 SPARC platforms
do *not* have FDISK tables and do *not* support the "p0" special file.
The dd command you suggest isn't applicable to the original question.

Accessing more than 8GB of an IDE disk on a S7 x86 platform isn't
officially supported but there are some tricks that make it somewhat
possibly (search deja.com or the Solaris on x86 group on egroups.com
for discussions about various >8GB hacks). Solaris 8 on x86 seems to
officially support >8GB IDE drives.

>
> dd if=/dev/zero count=1 of=/dev/rdsk/xxxxxs9
>

That doesn't do anything useful on either SPARC or x86 platforms.
SPARC platforms only support slices 0-7. On x86 platforms, the s9
slice is by convention the "alternates slice". Perhaps you were
thinking of the s8 slice which by convention is the "boot slice".
But that would also be the wrong slice to zero out. On the x86
platform the label starts in sector 1 of the Solaris FDISK
partition (sector 0 is the pboot sector and is required by the
BIOS). Furthermore the x86 label may be more than 1 sector long.
The s8 (boot) slice is *not* required to start in sector 0 of
the Solaris FDISK partition, that's just where it is normally
placed by the Solaris Install program and the format utility.
Since the s8 (boot) slice has a specific and unique tag in the
VTOC, it can be placed anywhere within the Solaris FDISK partition.

Using the dd command to fix an invalid or correupt label requires
way too much low level knowledge about the layout of disk drives.
Some of the information is here:


http://docs.sun.com/ab2/coll.47.8/SYSADV1/@Ab2PageView/32803;td=5?DwebQuery=s8
&Ab2Lang=C&Ab2Enc=iso-8859-1

The "proper" way to fix an invalid or corrupt label is to use
the format command. See:


http://docs.sun.com/ab2/coll.47.8/SYSADV1/@Ab2PageView/35249;td=5?DwebQuery=s8
&Ab2Lang=C&Ab2Enc=iso-8859-1


If you insist on using dd then you should be aware that on both SPARC
and x86 platforms there is no slice that is *required* to start in
sector 0 of the SPARC disk or sector 0 of the x86 Solaris FDISK
partition. But there is a (unenforced) convention that the s2 (backup)
slice starts in sector 0 and maps the whole SPARC disk or maps
the whole x86 Solaris FDISK partition.

On a SPARC platform the following sometimes works:

    dd if=/dev/zero of=/dev/rdsk/c?t?d?s2 count=2

(I'm not certain how large the SPARC label is but count=2 should wipe
out more than enough of it).

On a x86 platform the following sometimes works:

    dd oseek=1 if=/dev/zero of=/dev/rdsk/c?[t?]d?s2 count=3

Neither of the above work if the s2 slice isn't a conventional
"backup" slice.