Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cwjcc!ukma!uflorida!novavax!nanook
From: nanook@novavax.UUCP (Keith Dickinson)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Seagate ST-251-1 heads banging?
Message-ID: <982@novavax.UUCP>
Date: 5 Feb 89 04:11:12 GMT
References: <5060049@hpccc.HP.COM>
Organization: Nova University, Fort Lauderdale, FL
Lines: 65

in article <5060049@hpccc.HP.COM>, samc@hpccc.HP.COM (Samuel Chau) says:
> 
> I have a pair of Seagate ST-251-1 40MB drives (less than a year old) and have
> been experiencing what I would call a "head banging" problem.  The drives
> make loud "clunk clunk" sounds just before they are accessed at boot time.
> Entering disk partitioning software such as PARTED of SpeedStor also triggers
> the sounds.

The sound you hear is the actuator arm striking what is called the "outer
crash stop." This will not damage the drive in any way (as a matter of fact
it's designed to handle the stresses caused bye it), but it does indicate
a problem on the drive. 

On every STEPPER drive that Seagate makes (exceptions are the 400 series
and other stone aged drives) there is a pattern written on the disk called
an Index Pattern. This pattern is used to tell the drive when it is at one
of two places: 1> Track -1 & 2> Last Track +~3. These are used by the drive
when it first powers up to quickly locate the heads. If the index tracks
have somehow been erased (as it sounds), then the drive will be lost on
initial power up. It may also take it longer for the drive to recover in case
of a mis-seek.

The drive 'should' work for you just fine, but if the drive is under waranty
I'd suggest you trade it in just in case. After all, you can't be sure WHY
the index pattern was nuked to begin with.

> 
> <Long discussion on hard drive controllers removed>

Like I said. It's the drive, not the controller. Don't worry about it.
> 
> I have heard a rumor that Seagate might have removed an IR sensor from the
> ST-251-1 units so as to save manufacturing cost.  Could this be impairing
> the ability of the heads to re-seek to track 0?  Or is it that because of
> the lack of feedback from the sensor, the heads are being stepped in an
> open-looped fashion so they eventually bump against the stopper to make
> the sound?

Again, there is no sensor as you describe in the ST251. Those were used in 
the pre-historic 400 series (and such monsters :).

> Does anyone have similar experiences?  Any light shed on the subject will be
> highly appreciated.

I have a drive (ST-238) that I've been running for about 6 months without
any index pattern on it. It has worked ok. It sounds TERRIBLE on power up, or
if it mis-seeks, but the reliability of the data is excelent. The board
finaly went south on me and I had to get it repaired.
> 
> 
> Sam Chau
> HP Cupertino
> samc@hpda
> (408) 447-0238
> 
> #include <std_disclaimer.h>

Keith Dickinson
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