Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!tektronix!reed!kamath
From: kamath@reed.UUCP (Sean Kamath)
Newsgroups: comp.sys.apple
Subject: Re: More miscellaneous stuff
Keywords: AppleShare, Sourceror's Apprentice
Message-ID: <12142@reed.UUCP>
Date: 23 Mar 89 04:17:04 GMT
References: <545@madnix.UUCP> <27478@apple.Apple.COM>
Reply-To: kamath@reed.UUCP (Sean Kamath)
Distribution: na
Organization: Reed College, Portland OR
Lines: 35

In article <27478@apple.Apple.COM> mattd@Apple.COM (Matt Deatherage) writes:
>3.  Quick power cycles cause the machine to go bananas.
>
>Sounds to me like some of the RAM in that system doesn't power down very
>quickly, so some of the system still thinks that certain things which aren't
>in memory any more actually are still in memory.  Try swapping the memory
>card in that system with one in another system.  If the problem follows the
>card from system to system, take it to a dealer.

>Matt Deatherage, Apple Computer, Inc. | "The opinions expressed in this tome

(Matt, you have to learn how to get your editor to pu tthe little >'s
in there for you. .  :-))

Not quite right.  In fact, I'll bet it has nothing really to do with
the RAM.  It's the shutdown time of the 6502 (and, I assume, the
65816).  When you turn on the chip, it must be shuttled through the
reset cycle, which is controlled by a capacitor.  Once the machine is
"up" then that cap sits there all happy.  when the machine "dies" the
cap starts to discharge, and when the power get's snapped on fast
enough, it hasn't discharged enough to make the chip reset, and so the
chip thinks (maybe, maybe not, depends on a lot of things) that it's
either in some flaky mode or executing code.  Since Ram get wasted
about 15 -40 ns after shutdown, RAM is wasted, and the chip is
executing or managing garbage.  Also, the internal RAM of the chip
(the registers, kids) are flaked out.

Now, I may be wrong.  In that case, I feel like a flake.

Sean kamath
-- 
UUCP:  {decvax allegra ucbcad ucbvax hplabs}!tektronix!reed!kamath
CSNET: reed!kamath@Tektronix.CSNET  ||  BITNET: kamath@reed.BITNET
ARPA: kamath%reed.bitnet@cunyvm.cuny.edu
US Snail: 3934 SE Boise, Portland, OR  97202-3126 (I hate 4 line .sigs!)