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From: info-mac@uw-beaver
Newsgroups: fa.info-mac
Subject: HyperDrive
Message-ID: <340@uw-beaver>
Date: Thu, 3-Jan-85 00:43:22 EST
Article-I.D.: uw-beave.340
Posted: Thu Jan  3 00:43:22 1985
Date-Received: Thu, 3-Jan-85 23:45:02 EST
Sender: daemon@uw-beaver
Organization: U of Washington Computer Science
Lines: 32

From: Paul R. Johnson 

I have some more information from General Computer Company on
the HyperDrive.

When power is off the heads are moved to a landing pad and locked.
In that state they are rated good for 40 Gs.  When powered on and
running they are rated for 5 Gs.  G.C.C. used to have the heads go
to the landing pads if nothing had happened for some timeout period.
They now think this is not necessary and don't retract them during
normal operation.  They claim to have had no failures from shock or
vibration other than the "throw the Mac on the sidewalk" incident I
related previously.

With regard to maintenance and Applecare:  this is still up in the air.
They are talking with Apple about the effect of installation of a
HyperDrive on Applecare coverage.  G.C.C. is also thinking about offering
"HyperCare":  i.e., Applecare but also covering their own modificatoins.
They will get back to me on this when anything is decided.

I also enquired further about memory extension.  The way it works
is that their current 512K extension is done using 64K chips to extend
the existing 128K in the Mac.  They could "easily" substitute 256K chips.
This would give either 1664K, if only the daughter-board chips are replaced,
or 2Meg (2048K), if the existing 64K chips are replaced as well.  All of
this memory can't be used by vanilla Macintosh programs via Memory Manager
calls, but any program that wanted to use it directly could do so.

---Paul Johnson,  MIT LCS


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