Re: files appear corrupt, but aren't; kernel bug?
>>>>> "D" == Dan Christensen <jdc@jhu.edu> writes:
D> Over the past few hours, my potato machine has been behaving very
D> strangely. Many of the files on my hard drive or which I read from
D> cdrom have minor errors. Specifically, at a random point in the file,
D> two consecutive bytes are changed to 160 and 192 (240 300 octal).
D> Moreover, this often repeats every 4194305 bytes! (That 2 to the 22nd
D> power, plus 1.) Only large files seem to be affected, and this makes
D> sense given the large gap between the bad bytes. However, I believe
D> that the files on the disks are fine because the problem goes away
D> sometimes. For example, during a period when the computer was
Hmmm, I would suspect either memory, or problems with the SCSI bus.
For SCSI problems, it could be due to termination (only external,
active termination should be used), or the cables are marginal (or
marginally too long). But it kinda makes sense that it might show up
only on long files -- you are stressing the system more. Or the disk
is starting to die...
For memory, are you running with fake-parity, true-parity, or ECC
memory? The former can gererate spurious errors like you are seeing
without otherwise being detected. I spend the extra money on ECC
memory, because I don't want any hidden errors...
Oh, and make sure that you have parity enabled on the SCSI bus
peripherals, too.
--
More Important Drivel from:
Scott Henry <scotty@sgi.com> /\/\/\ http://reality.sgi.com/scotth/
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