On Sun, 28 Jun 2009 19:22:03 +0200, Roberto Ragusa wrote: > Andy Campbell wrote: > >> Hmm always out by 1 ... >> >> [trantor] ..mp2/tmp/src $while true >> while> do >> while> cp file1.zip new.zip ; cmp -l file1.zip new.zip while> done >> 107757013 271 270 >> 109383125 206 207 >> 85093653 373 372 >> 77726613 206 207 >> 85093653 373 372 >> 85899797 373 372 >> 38258517 373 372 >> 109383125 206 207 >> 107757013 271 270 >> 109383125 206 207 >> 142459477 126 127 >> 107757013 271 270 >> 40550997 171 170 >> 85093653 373 372 >> 107757013 271 270 >> 110261013 371 370 >> 62581653 371 370 >> 109383125 206 207 >> 110526037 71 70 >> 109383125 206 207 >> 40550997 171 170 >> 77726613 206 207 >> 109383125 206 207 >> 107757013 271 270 > > The error is always in the last bit. > And there is also a strong similarity on the final part of the position > error, if expressed in hexadecimal. > > If you paste your numbers into this command: > > $ while read a b; do printf %08x"\n" $a; done > > you get this: > > 066c3dd5 > 06850dd5 > 05126d15 > 04a20395 > 05126d15 > 051eba15 > 0247c755 > 06850dd5 > 066c3dd5 > 06850dd5 > 087dc255 > 066c3dd5 > 026ac255 > 05126d15 > 066c3dd5 > 06927315 > 03baeb95 > 06850dd5 > 06967e55 > 06850dd5 > 026ac255 > 04a20395 > 06850dd5 > 066c3dd5 > > The errors are all of kind: ......X5 where x=1,5,9,d. > > So the errors appear only at spots with a distance of 16*4=64 bytes. > > Strong suspicion on your hardware: CPU (defective L2 cache line?), > chipset or memory (did you try one 4 GiB and then the other 4GiB stick?) > > Oh, hardware problems could also be caused by a defective power supply > or... a motherboard not well screwed on the chassis (this one made me > mad some years ago). > You could also try something related to power/speed management. > > The only alternative is a kernel bug, but as it is touching only one bit > it is not likely. > > Best regards. > -- > Roberto Ragusa mail at robertoragusa.it Thanks The memory is 4*2Gb sticks - I've tried each pair individual. Also left memtest running with full 8gb today - passed 4 times. Also don't seem to have problems using /tmp which is mounted as tmpfs, so don't think its memory, or CPU - seems to be hardware related directly to writing to physical disks. I'll pull it all apart and rebuild it in the week - I have a spare motherboard I can swap in. Hopefully not the power supply as it was an overkill, never have to worry about PSU purchase of a 1000W Enermax Galaxy. -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
