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Path: utzoo!dciem!nrcaer!xios!greg
From: greg@xios.XIOS.UUCP (Greg Franks)
Newsgroups: comp.arch
Subject: Re: Disk Striping (description and references) plus class brief
Message-ID: <351@xios.XIOS.UUCP>
Date: Wed, 19-Aug-87 08:30:52 EDT
Article-I.D.: xios.351
Posted: Wed Aug 19 08:30:52 1987
Date-Received: Sun, 23-Aug-87 10:12:02 EDT
References: <2432@ames.arpa> <3721@well.UUCP> <2838@phri.UUCP>
Reply-To: greg@sdn.UUCP (Greg Franks)
Organization: XIOS Systems Corporation, Ottawa, Ontario, Canada
Lines: 21


In article <2838@phri.UUCP> roy@phri.UUCP (Roy Smith) writes about
operating disks in a vacuum to get around supersonic effects and the
nasty consequences thereof.  I always thought that disk heads "flew"
over the media.  Removing the air would make vertical head positioning
somewhat challenging.  I also believe that one wants to get the heads as
close to the media as possible to obtain the best recording density. 

#	I understand that in big power plants, the insides of the
#generators are filled with hydrogen instead of air because the speed of
#sound is faster so the rotor tips don't go supersonic.  

I think power generators use hydrogen for cooling purposes more than
anything else.  I could be wrong - It's been awhile since I've been
around 500 Megawatt generators.  (They turn at 3600 RPM, so if someone
wants to get inspired and calculate the speed of the rotor tips, feel
free!)
-- 
Greg Franks             XIOS Systems Corporation, 1600 Carling Avenue,
(613) 725-5411          Ottawa, Ontario, Canada, K1Z 8R8
seismo!mnetor!dciem!nrcaer!xios!greg        "Vermont ain't flat!"