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From: johnw@astroatc.UUCP (John F. Wardale)
Newsgroups: comp.arch
Subject: Re: Disk Striping (description and references) plus class brief
Message-ID: <414@astroatc.UUCP>
Date: Fri, 21-Aug-87 16:36:50 EDT
Article-I.D.: astroatc.414
Posted: Fri Aug 21 16:36:50 1987
Date-Received: Sun, 23-Aug-87 04:08:26 EDT
References: <cV=3A8y00UoB0qA0AT@andrew.cmu.edu>
Reply-To: johnw@astroatc.UUCP (John F. Wardale)
Organization: Astronautics Technology Cntr, Madison, WI
Lines: 33

In article ??? (Walter Lloyd Wimer, III) writes:
>Then why not use helium instead?  It's mass is about four times that of
>hydrogen, and I don't know the speed of sound in each gas offhand, but it
>might just work. . . .
1:  Hydrogen (H2) has mass 2   Helium [its NOT He2] has mass 4
2:  I think the formula uses squre-root of the gas's mass.
	so H2 is only 40% better than He which is a ~2 times better than air
---------------------------------------------

		Advancing Disk Tecnology

I fear that disk makers can not afford to design an exotic 8" He
disk that spins at .8 Mach  (3600rmp=.2mach at 14" ... 3600
*3[size] *5[mach1] *2 for He *.8[tolerences and slop
give a speed of 86,400rpm or 1440rps 

Figure a 3year design cycle and 5 year life.  Said unit will have
to compete with DRAM memorys of 5 to 8 years from now!
How much would said disk be worth in an age where 16M-bit
chips are old-hat and people have 64M-bit chips working "in the
lab"  ???   (that's only 128 chips per GIGA-byte!!!!)

When did someone first say "The days of rotating magnetic memory
are about to end" ??  5, 10, 15 years ago ???

Does anyone else agree that this *WILL* happen in the next 5 or so
year???

-- 
					John Wardale
... {seismo | harvard | ihnp4} ! {uwvax | cs.wisc.edu} ! astroatc!johnw

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