Micropolis - moon or bust?

From: jpero_at_cgo.wave.ca <(jpero_at_cgo.wave.ca)>
Date: Mon Dec 22 09:04:50 1997

Hi Hotze!

And, suited to anyone interested too.

This does not apply at all. MTBF is stat based on random pick and
project it and it's bandied about purely for marketing/relibility,
*Hmmtph!*. A year is about 8760 hours long and my real experience
tells me average especially for low end to barely medium end have
average of 3 years at MOST due to bit of substandard production used
to keep costs down. I have talked to someone and told me the major
differences in controlling this reliability (means it to last years
and years and years) was in all types of balancing, bearing runout,
top quality bearings and has rubber seals on them, coated housings
and very rigid design, spindle axle runout, spindle runout all made
to VERY TIGHT specs that micropolis used. Also the design of heads
arms and balance, flexing, damping and pulse train profile to make it
"cushy" seeks yet rapid is very important to lifespan of the HD.

I've opened all kinds of hds including several failed micropoils
13xx series. I understood why. Tandon/early 40mb WD's used fine
regular ball bearings with bit looser specs, rack/p gearing, poor
designs, all of them died in short order, I have not seen one that is
still alive locally or at other few cities, same with miniscribe also
to lesser degree except for their rack/p gearing the worst one. WD
also did use that quality even with voice coil until recently
(hopefully!), ditto to early st251 and st125 series as well as few
early ST1144A/ST3144A series. DaeYoung indeed died young true to its
name, ditto to Kalok and Kocera. I did open the few Quantums
including ELS 85, this used a sealed bearing and manufacturing finish
and all was pretty good as top end types. I was glad that Quantums
learned their past mistakes quickly (My friend in computer business
sold over 300 quantums of all kinds from low end to mid and none came
back. There was one hd that dropped down flight of hard stairs that
worked for short time...true story.) as well as Seagate if even bit
slower. Maxtor is hit and miss and still have compatiabity problems,
(One brought up appox under 40 850mb, MTBF was in that range Hotze
indicated, lot and all of them died towards 1 year then failed in
large bunches, none survived past a year and half and they're not
that heavy use! Primarily in school use in their PC's teaching s/w
not h/w!) Have a 1355 w/ date production of about 1987 and couple of
CDC's and one Priam that had made when QC was high. All except for
1355 are appox 60-80mb full height catorgy.

There are several failures recently related to installer errors:
found several that used WD type seal that use special tape band to
seal out seam that meets by both top shell and the chassis, ditto to
several seagates using this This is no excuse that blamed on sharp
cage's edges. All one is to be more careful and take and install it
carefully without tearing those sealing band! Several quality hds
failed but I was able to tell it were caused by installer error and
imporper install. (Microscience did a research and found that 1"
drop on hard surface was enough to subably damage it. I also chalk
that up to installer skipping (I hear it!) during installing hd's
using philips screws along with general bangs during handling.)
General warning issued: Quantum fireball ST series notch cutouts to
allow normal PC screws have ridden of, requiring stubby screws.
But as a general rule, I apply this stubby screws appoach to all
hd's.

Well, for now, If anyone have anything more to point out, I can try
to point out and see other side experiences.

I as being curious tinker and a quest for failure analysis is
valueable experience and more importantly, indictor of hd makers'
commitment to contiuned QC on all levels.

Jason D.

> What about JTS (with their 500,000MTBF), the company that owns what's left
> of Atari? (Their drives are on the top of MY list for quality.)
> Tim D. Hotze

nip!
Received on Mon Dec 22 1997 - 09:04:50 GMT