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From: info-mac@uw-beaver (info-mac)
Newsgroups: fa.info-mac
Subject: Re: Upgrading your own MAC memory
Message-ID: <1256@uw-beaver>
Date: Thu, 19-Jul-84 13:41:45 EDT
Article-I.D.: uw-beaver>.1256
Posted: Thu Jul 19 13:41:45 1984
Date-Received: Fri, 20-Jul-84 04:35:39 EDT
Sender: daemon@uw-beave
Organization: U of Washington Computer Science
Lines: 31

From: David Chase <rbbb@rice.ARPA>
I can't stand it any longer.  I think people planning to do their own 512k
upgrades are crazy.

1) Who will fix a Mac that has been user-munged?  (What crazed fool would
offer to maintain a Mac when the user doodles with the innards?)

2) What will you do when the repairman wants to do a board swap?  Tear out
all the 256K chips so you can reinstall them in the replacement board?

3) I recommend against installing sockets because of bad thermal properties;
chips will tend to die faster (and the Mac is already very hot inside).  I
have had some experience with this, using socketed Mostek memory and
soldered DEC memory in a VAX 11/780.  The Mostek boards (2.5 Meg of 16K
chips) would lose about 10 chips per year; the DEC boards (1.5 Meg) lost
maybe 1 chip every two years (wert.pa@xerox.arpa may correct me on this).
The 780 ran MUCH cooler than the Mac, so I don't expect chip life in the
Macintosh to be any better (though there aren't as many chips to break).

4) Adding more chips inside the Mac is also a loser, because you may cook
the insides with the additional heat load.

5) If you must attack your Mac after all this, consider CMOS memory instead.
It uses practically no power and runs very cool.  While you are changing
things, go whole hog and add a battery backup to your memory so that (maybe)
the Mac need never be rebooted (you'll need to suppress the reset that
probably comes from a power-up).  It does cost a little bit more, but so it
goes.  (Note - I have a friend who worked on the HP Nomad, so I am right now
a big fan of CMOS).

drc