Disk platters and water (was: Re: NOVA4 6070 disk booboo)

From: Ashley Carder <wacarder_at_usit.net>
Date: Thu Feb 3 09:19:17 2005

> Jay> Wonder what the head-disk gap was on a drive of the IBM 1311
> Jay> vintage.
>
> Probably not dramatically larger than that of the RK05. I don't
> remember the number. It was shown on a drawing on the disk pack bags
> that DEC created to remind people not to put fingerprints on the
> platters. I remember it showed a fingerprint, a dust particle, and a
> hair, drawn to scale next to the head height. The fingerprint was
> about 3-5x the flying height, so measure a fingerprint and find
> out... It also was perhaps 1/50th of a hair. So perhaps a few
> micrometers?
>
> paul

I knew I had seen the same diagram, so I looked in my RK05 manual
and found the picture, which shows the following:

Head flying height: 100 microinches
Smoke particle thickness : 250 microinches
Fingerprint smudge: looks about 2x the size of a smoke particle
Lint and dust: looks about 2/3 the thickness of a hair
Hair : 4/1000 of an inch

Reference : Page 1-17 of the RK05/RK05J/RK05F maint. manual

Ashley
Received on Thu Feb 03 2005 - 09:19:17 GMT