yet another UNIXpc HD tale

[Thad P Floryan]

Re: yet another UNIXpc HD tale
comp.sys.att,unix-pc.general


wjc at ho5cad.ATT.COM (Bill Carpenter) in <WJC.90May3175246 at hoswjc.ho5cad.ATT.COM>
writes about his problems with a Seagate ST251 HD.  Sigh.  :-(

I had ten (10) of those suckers go belly-up on me, all after about 14 months
(two months after warranty expiration).  And I was in contact with the QA mgr
of Seagate in Scotts Valley CA and design engineers also at that facility to
rectify the problem.  Let's just say that I'll *NEVER*, *EVER* buy anything
mfd or sold by Seagate again; and I was deeply saddened to hear of Seagate's
acquisition of Imprimis (CDC's disk drive facility).  At present I stick with
quality drives such as Maxtor, Quantum, and Conner.

As I've posted to numerous newsgroups over the past several years, the problem
is a manufacturing defect; specifically "stiction" caused by excess lubricant
on the platters causing the heads to be "stuck" when they're parked.

Not to bore everyone again (though I have probably close to 1Mbyte archives
on disk problems of this nature), the solution is to either junk the drives
or to have them replattered; nothing else will FIX a drive with the problem.

There IS a temporary solution which will permit you to spin-up the drive and
retrieve your files.  Believe me, I was sweating icicles before I stumbled on
this solution several years ago.  *ALL* hard drives WILL FAIL; the only unknown
is "when?"  Thus, I have NO sympathy (anymore :-) for anyone who doesn't have
and uphold a HD backup regimen.

With all that said and done, here's how you can get the drive to spin up to
where you can retrieve your files:

	Remove the ST251 drive from your system.  Turn it upside down so that
	you see the printed circuit assembly.  Notice there's a center spindle
	which is the main shaft, and off to the corner is another spindle
	which is the stepper motor shaft.  Put the tip of your index finger
	on the stepper motor shaft and twist it back and forth a few times;
	you don't have to twist too far, and BE GENTLE ... your data IS still
	on the drive!

	Remount the drive into your system, power up and boot, then get your
	files off ASAP.

What you do with the drive after this point is up to you.  There are many
companies which will replatter your drive.  The specific problem (as seen
under microscope) with the ST251 is excess lubricant collecting in the PARK
area ('cause the heads during normal operation push the excess out beyond
cylinder 0 and INTO the center area (the PARK zone) much like windshield wipers
on a car's window) and a meniscus forming which effectively "glues" the heads
into the PARK area.

As I wrote to Usenet (and later found plagiarized in several technical mags),
you can demonstrate the phenomenon using two glass plates and a few drops of
water: place the dry plates together and note you can slide them around 
easily; now put a few drops of water between the plates and just TRY to move
or separate them.

Most of the ST251 that fail are assembled in Singapore based on hundreds of
e-mail replies I've received; assembly line workers are over-lubing the
platters and the (sloppy or non-existent) QA doesn't detect the problem since
it's not until the drives are in service for awhile that a noticeable excess
accumulates in the PARK area.  The lubricant is "normally" one or two
mono-molecular layer(s) thick; the defective drives exhibit signs of more than
5 layers of lubricant.  The lube CANNOT be removed inexpensively hence the
need to replatter if you still wish to keep the drive.

Thad

Thad Floryan [ thad at cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]