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From: jcburt@ipsun.larc.nasa.gov (John Burton)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: Hard disk poops out when "warm"
Message-ID: <1991Jun3.200730.10013@news.larc.nasa.gov>
Date: 3 Jun 91 20:07:30 GMT
References: <1991Jun3.032541.20012@informix.com>
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In article <1991Jun3.032541.20012@informix.com> robs@infmx.informix.com (Robert Schneider) writes:
>
>A question for all you hard disk mavens:
>
>I've got a Bleeding Edge Model D 4.77 MHZ PC, with
>a 30 mb hard drive.  I've noticed something fairly
>peculiar as follows:
>
>When "cold" e.g. freshly booted, I can access the hard
>drive no problem.  After about 5 minutes or so, I begin
>to get seek errors.  No matter what I do, I can't get at 
>the damn drive.  Running 'fdisk' off drive A, I am
>told that the FAT is gone and that there is no partition
>on C.  Of course, this is not the case.  If I power off
>the PC and *immediately* turn it back on, drive C is
>still unavailable.  If I wait an hour or so, and then power
>up, the problem repeats itself as originally stated, e.g.
>5 minutes of pleasure followed by infinite pain.
>
>Does anyone have an idea about what this could be?  I can
>use the PC basically as a one floppy machine right now.
>I'd like to have the hard disk back.
>
>Thanks to any and all who reply.
>
>Rob

I'm not sure, but it sounds like a thermal expansion problem to 
me...When was the last time you did a low level format / fdisk
on you drive? (not recently?) when/if you did do a LLF/FDISK,
did you do it when the disk was cold (just after bootup) or was it
warm (after operating for awhile) ? 

with a stepper motor disk (which you probably have) the read/write
heads are positioned relative to the stepper motor/mounting, not
relative to the disk platters. when the disk heats up, the platters
expand a little => the heads don't look at exactly the same place on
disk as when the disk is cold. Just one bit in error could make the
controller think the FAT is gone...

A possible solution would be to turn the machine on & let it warm
up for awhile (10-20 mins) then do a low level format / fdisk.
you would then do a high level format (DOS FORMAT command).
after all this, you *should* be able to use the disk normally...

just remember...
BACK UP YOUR DATA!!!! this procedure will totally destroy all the
data on you hard disk. There is NO WAY to recover data after doing
this (well, not that I know of anyway...even Norton's UnErase won't
help)

Good luck...

John

+--------------------------------------------------------------------+
| John Burton                                                        |
| G & A Technical Software                                           |
| jcburt@gatsibm.larc.nasa.gov                                       |
| jcburt@cs.wm.edu                                                   |
|                                                                    |
| Disclaimer: Hey, what can I say...These are *my* views, not those  |
|             of anyone else, be they employer, school, or government|
+--------------------------------------------------------------------+