Posted by Bill Vermillion on 12/20/05 20:55

In article <g3cto19t9ittasvp05hu08pgtp7p2tukcq@4ax.com>,
NunYa Bidness <nunyabidness@nunyabidness.org> wrote:
>On Wed, 30 Nov 2005 17:31:46 -0800, "Gene E. Bloch"
><spamfree@nobody.invalid> Gave us:
>
>>Mmmm. I've had hard drives freeze up. Some could be brought to life
>>with CPR (tap them, not too gently or too hard, with the handle of a
>>screwdriver). One or two never came back to life.
>>
>>Admittedly, these were FM and MFM drives of about 20 to 40 MB each
>>(yes, megabytes). Perhaps not the latest technology today...
>>
>>However, there are other failure modes available for an enterprising
>>hard drive.
>>
>>Gino
>
> There is a big difference between a failing stepper motor and what is
>inferred by the remark "freezing up". As I recall, there were no hard
>drives that did not contain dry bearings... ie nothing to seize. If
>said bearing had a problem to the extent that the drive platter would
>seize up, the slop would have crashed such a drive long before any
>such seizure ever took place.
>
> I had several MFM drives of various sizes, and even still have a
>Tandon 10MB, the original XT HD. There are no "FM" drives to my
>knowledge, as it is not an interface that ever existed.

Not in hard drives that I recall. But the original FM specs stored
one clock bit between each data bit. The MFM became self-clocking
- and could actually be called RLL 1,3.

> MFM RLL ESDI SCSI were some of the original small form factor
>methods available. The big mainframe drives were originally termed
>"winchester" drives, but they had a 12" form factor. They didn't
>freeze up either.

Don't forget the intermediate form factor between the big drives
and the 5.25" drives - the 8" form factor. My first HD was
an 8" 8MB HD - it's been along time but I think it was
a Shugart SA-4000.

Bill

--
Bill Vermillion - bv @ wjv . com

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