Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!rutgers!usc!samsung!sdd.hp.com!hplabs!hpl-opus!hpcc05!hpdmd48!alien
From: alien@hpdmd48.boi.hp.com (Tom von Alten)
Newsgroups: comp.sys.apollo
Subject: Re: Disk drive repair
Message-ID: <16650005@hpdmd48.boi.hp.com>
Date: 13 Oct 90 22:21:45 GMT
References: <2096@apctrc.UUCP>
Organization: Hewlett Packard - Boise, ID
Lines: 19

John Thompson says
> I'm not aware of any drives _without_ mechanical brakes.

We make some here.  I have looked closely at many designs of the
last few years, and I overlooked or have forgotten about any mechanical
brakes I've seen.

IMHO, a brake being "needed at all times to keep the disk from spinning
freely" sounds excessive.  The amount the disk is likely to spin freely
in its lifetime is small compared to the stress from start/stop.  Brakes
do make sense for start/stop, but why not use that energy to send power
back into the grid when you shut your drive off?   ;-)

If my choice is a drive that won't spin up _with_ a brake, and one that
will _without_ a brake, I'd choose the latter!

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Tom von Alten		email: alien@hpdmlad.boi.hp.com
                        Hewlett-Packard Disk Mechanisms Division