Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!uwvax!astroatc!johnw
From: johnw@astroatc.UUCP (John F. Wardale)
Newsgroups: comp.arch
Subject: Re: Higher transfer-rate disks
Message-ID: <403@astroatc.UUCP>
Date: Mon, 17-Aug-87 16:23:41 EDT
Article-I.D.: astroatc.403
Posted: Mon Aug 17 16:23:41 1987
Date-Received: Tue, 18-Aug-87 06:21:19 EDT
Reply-To: johnw@astroatc.UUCP (John F. Wardale)
Distribution: world
Organization: Astronautics Technology Cntr, Madison, WI
Lines: 29
Keywords: disk vacuum magnetic


A few comments:

It is best to run disks in posivite proessure to keep out unwanted
"crud".   Flying the heads in H2 or He would get you (maybe) twice
the speed (of air) before you hit mach.  Reducing pressure gets you 
less than this.

Some (fuji I'm fairly sure) makes Parrallel Transfering Disks that
get 10 to 20 mega-bytes per second.  They are head/surface, like
normal disks, but there's a copy of the tranfer logic for each
one!   Benchmarks I've seen/heard about (multi-user unix usage
patterns) indicate that you lose about half of this, but at 5 or
10 times rates, you gain 2.5 to 5 times the "effective" transfer.

[ Speculation on the lose: the heads are fixed together, and you
  may not always want the "disk-cylendar" so the seek-delays hit 
  you twice as hard. ]

			John W

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
Name:	John F. Wardale
UUCP:	... {seismo | harvard | ihnp4} !uwvax!astroatc!johnw
arpa:   astroatc!johnw@rsch.wisc.edu
snail:	5800 Cottage Gr. Rd. ;;; Madison WI 53716
audio:	608-221-9001 eXt 110

To err is human, to really foul up world news requires the net!