From: Bill Stewart <stewarts@ix.netcom.com>
Date: Tue, 27 Aug 1996 16:55:50 +0800
To: mccoy@communities.com (Jim McCoy)
Subject: Re:Edited Edupage, 18 Aug 1996 [SATELLITES]
Message-ID: <199608270627.XAA02553@toad.com>
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At 12:35 AM 8/21/96 -0800, mccoy@communities.com (Jim McCoy) wrote:
>You want to avoid moving parts like the plague in orbit.  They eventually
>wear out or fail and once that happens you have a very expensive piece of
>junk in orbit.  Solid-state storage is the _only_ way to go if you want to
>avoid things like neding to pressurize the drive (eliminating any cost
>advantage over solid-state.) 

Why do you need to pressurize the drive?  Most hard disk drives
for the last N years have been airtight sealed containers,
haven't they?  (Removables are different, of course.)

I'd worry far more about the stresses of launch bothering
the drives.

> Its not like you can go up to swap a dead drive
> out you know...

You do obviously want RAID and/or mirrored drives.

> Solid-state

Most government space computer equipment has expensive RAD-hardended RAM;
it's much cheaper and probably more effective to just use conventional
RAM with ECC and shield it a bit.  At least at one time, the most powerful
computer on the Space Shuttle was the Compaq 386/25 laptop that one
of the astronauts brought along for some non-mission-critical work;
most of the built-in computers were 1 MIPS or less.

>The big problem is that no one has data that is worth protecting enough to
>make such a venture pay off.

Yup.  Ego would be a good motivation, if you know somebody with enough
spare cash :-)

While it would be nice to have satellites around all the time,
even one or two smallsats could provide services on a several-times-daily
basis which would be enough to do private email.

#			Thanks;  Bill
# Bill Stewart, +1-415-442-2215 stewarts@ix.netcom.com
# <A HREF="http://idiom.com/~wcs"> 	Reassign Authority!