a new hard-drive in a 2y/o laptop

Ian Smith smithi at nimnet.asn.au
Thu Jan 6 09:06:55 UTC 2011

On Wed, 5 Jan 2011, Chris Brennan wrote:
 > On Wed, Jan 5, 2011 at 12:44 AM, Ian Smith <smithi at nimnet.asn.au> wrote:
 > >
 > > Saw Chris' later message that -F isn't there for him, but here's what
 > > should be, on the data, the sure-fire way to clobber that last sector:
 > >
 > >  dd if=/dev/zero of=/dev/ad4 oseek=1465149167
 > >
 > > which command SHOULD report just 512 bytes written (we're sure it can't
 > > write past the end of the disk with no count specified), after which:
 > >
 > >  dd if=/dev/ad4 iseek=1465149167 | hd
 > >
 > > SHOULD show zeroes from 00000000 to 000001ff (ie next block 00000200)
 > > If not, there really must be some hardware issue with writing?
 > >
 > > Hopefully getting there!

 > Fixit# sysctrl kern.geom.debugflags=16
 > kern.geom.debugflags: 0 -> 16
 > Fixit# dd if=/dev/zero of=/dev/ad4 oseek=1465149167
 > dd: /dev/ad4: end of device
 > 2+0 records in
 > 1+0 records out
 > 512 bytes transferred in 0.0100001 secs (51195 bytes/sec)

So that's right.

 > Fixit# dd if=/dev/ad4 iseek=1465149167 | hd
 > 1+0 records in
 > 1+0 records out
 > 00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 > |................|
 > 512 bytes transferred om 0.009863 secs (51912 bytes/sec)
 > *
 > 00000200

And that's right - the GPT secondary header is now gone.

 > restarting and back to sysinstall from BETA1 is nice dice ... same original
 > error ... can I just zero the whole drive?

Sure you can - but I'd be (happy to be) surprised at this point if it's 
going to do much good.  If nothing else it's a full surface write test, 
and you could check afterwards that it's all been zeroed, hd showing 
just a few lines (as above) over the whole disk (dd if=/dev/ad4 | hd)

We seem to have ruled out the remnants of a GPT problem, having Bruce 
and Warren to thank for pointing it out; it's bound to catch others.

Your dd of the first 71 sectors looked right, MBR looks ok, sectors 1-62 
are zeroes, boot1 and boot2 from sector 63-70 seem normal, after you 
used 'W' to write anyway; can't say for sure that the bsdlabel is ok, 
but see no reason to suppose otherwise.  What says 'bsdlabel ad4s1' 
while you've still got one?

Just be sure NOT to use the 'A' option for auto-partitioning again; I'm 
sure I saw some problem with that on 8.1, not sure if it's fixed on 8.2 
(Bruce?) so I suggest allocating the BSD partitioning you really want.

Failing that, I can't see other than a hardware issue, unless somehow 
sysinstall is broken and you may do better manually running fdisk and 
bsdlabel and newfs per Handbook and manuals?  If that worked you could 
still use sysinstall, skip fdisk and labelling steps and install the 
distributions, ports tree, doc packages and other sysinstall goodies.

If it still persisted after that I'd subscribe and report the issue to 
freebsd-stable in as much detail as needed for some more fresh eyes.

cheers, Ian

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