IBM Cosmic-ray protection (was Named PTF's - was CPF324A)

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FWIW, I went to IBM's website, and did a search on 'cosmic ray' and came up
with a whole slew of documents.
(http://www.ibm.com/Search?v=11&lang=en&cc=us&q=cosmic+ray) Not only have
the made changes to systems to protect them from cosmic rays, they are still
doing it. (One paper even stresses that cosmic rays were a primary
motivation behind the development of ECC RAM, and goes on to say that most
servers are still vunerable.)

This ought to make it clear just how serious IBM is about server
reliability. :)

From: "MCPARTLAND, Stan" <stanley.mcpartland@bently.com>
> From: Steve Landess
>
> This may be stuff of urban legend, but I heard about it in the mid-90's, I
> believe...
>
> Apparently some AS/400 customers were having intermittent problems with
> their systems crashing.  After investigation, it was found that if the
> system was located above a certain elevation, gamma rays would zap memory
> bits between refresh cycles, causing the system to go down.
>
> The  fix was a PTF that caused memory refresh to occur more frequently

I recall that PTF.  Used to have the cover letter, but lost it over the
years.  The cover letter listed cosmic rays as the cause of the problem.  It
was a hyper PTF that was released in 1989 or 1990.