Is this a sign of memory going bad?

Sandy Rutherford sandy at
Fri Dec 3 02:57:02 PST 2004

If the goal is simply to stress-test the memory, just take a huge file
and write a shell script loop to gzip it and ungzip it ad infinitum.
I used this technique a while ago to ferret out some memory problems.
In this case, the bad memory manifested itself as gzip eventually
reporting an error that the file was corrupted.  I'm not saying that
this is a fool-proof way of finding bad memory, but it did the job at
the time.


>>>>> On Thu, 2 Dec 2004 12:53:44 -0600 (CST), 
>>>>> Chris Dillon <cdillon at> said:

 > On Thu, 25 Nov 2004, Chuck Robey wrote:
 >> I don't want to embarrass anyone here, but something needs to be 
 >> said. Note this next sentence carefully: THERE IS NO SUCH THING AS A 
 >> ....

 > The memory-test programs are not entirely worthless.  Just recently we 
 > had a lab of PCs where some of them would go wonky and randomly lock 
 > up hard.  This was happening for months and we couldn't put our finger 
 > on the problem.  We thought maybe it was something in our Windows 
 > build, so we tried booting Microsoft's stand-alone memory tester (yes, 
 > they have one, and I'm not sure where I got it, MSDN perhaps?), very 
 > similar to memtest86.  After a random number of test passes, sometimes 
 > 100+ passes (many hours, overnight), some of the machines would lock 
 > up.  No errors indicated, they just froze.  Oops.  Definately NOT a 
 > software problem.  After fiddling around with some of the 
 > clock/voltage related BIOS settings, putting new thermal compound 
 > between the CPUs and heatsinks, reseating cards and memory, placing 
 > the PCs inside a hexagram drawn on the floor and dancing nak... 
 > nevermind... we got them to run the tests continuously through our 
 > entire 4-day Thanksgiving weekend without problems.  For the last 4 
 > days (including today), we haven't had any problems with them.

 > So, these memtest programs can at least be valuable stress-testing 
 > tools but be prepared to run them for hours or days at a time before 
 > they will catch something. :-)

 > -- 
 >   Chris Dillon - cdillon(at)
 >   FreeBSD: The fastest, most open, and most stable OS on the planet
 >   - Available for IA32, IA64, AMD64, PC98, Alpha, and UltraSPARC architectures
 >   - PowerPC, ARM, MIPS, and S/390 under development
 >   -

 > Q: Because it reverses the logical flow of conversation.
 > A: Why is putting a reply at the top of the message frowned upon?

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