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From: mcgrant@elaine30.stanford.edu (Michael Grant)
Newsgroups: comp.sys.handhelds
Subject: Re: Interesting effect (HP48)
Message-ID: <1991Feb14.193917.3886@portia.Stanford.EDU>
Date: 14 Feb 91 19:39:17 GMT
References: <59716@eerie.acsu.Buffalo.EDU>
Sender: news@portia.Stanford.EDU (Mr News)
Organization: Stanford University - AIR
Lines: 27

In article <59716@eerie.acsu.Buffalo.EDU> 
cloos@acsu.buffalo.edu (James H. Cloos) writes:
>There MAY be an obscure
>problem, or I may just have gotten a thick spurt of some interference
>(cosmic rays?) that mucked up RAM just enough to crash.  
>
>P.S.	I'm currently leaning toward some kind of RAM-affecting interference.

It could be a 'soft error', which is simply the interaction of radiation
with the memory, causing a temporary read error.  I've worked in memory
failure analysis before, and soft errors are enough of a problem that they
are used as a measure of the robustness of a new design.  They bombard
the thing with alpha particles, and see if anything goes wrong.  Of course,
this means that they get many more errors than anyone else ever will.

Well, to be perfectly honest, there is no way of knowing if this is 
the reason why the calculator crashed, but, despite all semiconductor
companies' efforts to prevent them, they still crop up--especially since
memory cell size keeps shrinking (the lower a cell's capacitance, the fewer
the number of electrons, the higher the susceptibility).

Hell, for all I know, it could be completely irrelevant to this particular
crash--I've never known a bug in my life to be attributable to anything but
software error.  But, your mention of cosmic rays brought this to mind.

Just a wild-eyed suggestion,
Michael C. Grant