[Beowulf] Not quite Walmart, or, living without ECC?

[David Mathog]

Michael Will wrote:

> We have found that linpack is by far the better memory tester than
> Memtest86+. 

So now we have a report of a second method that finds more memory 
problems than memtest86+.  Can somebody please shed some light on why
these two programs find defects in memory that memtest86+ doesn't?
Or is it that they find defects in other parts of the hardware,
external to the actual RAM, which manifest as memory errors?  The
key distinction being that swapping memory sticks will cure the
former but not the latter.

In any case I'd like to know what it is about linpack/memtester which
lets them find memory faults that memtest86+ doesn't.  Presumably
whatever this magic sauce is could be added to memtest86+, once
again resulting in a tiny memory tester which can run without the rest
of linux.  That is a desirable goal, since the rest of linux sits on a
largish chunk of memory which cannot be tested with either linpack or
memtester, and which is critical to system stability.

Regards,

David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech