Re: md5sum: md5sum -c gives variable results

[Jim Meyering]

"Tarje Killingberg" <address@hidden> wrote:
> I am getting variable results from md5sum with the -c switch. I suppose a
> bug in md5sum is unlikely, but maybe you have some ideas for what I can do
> to find out what is going on. I have included some commands and their output
> to describe the situation and some other information.
>
> # md5sum -c test06.avi.md5 ; md5sum -c test06.avi.md5 ; md5sum -c
> test06.avi.md5 ; md5sum -c test06.avi.md5 ; md5sum -c test06.avi.md5 ;
> md5sum -c test06.avi.md5 ; md5sum -c test06.avi.md5 ; md5sum -c
> test06.avi.md5 ; md5sum -c test06.avi.md5
> test06.avi: FAILED
> md5sum: WARNING: 1 of 1 computed checksum did NOT match
...
> test06.avi: OK
> test06.avi: FAILED
> md5sum: WARNING: 1 of 1 computed checksum did NOT match
> test06.avi: OK
> test06.avi: OK
> test06.avi: FAILED
> md5sum: WARNING: 1 of 1 computed checksum did NOT match
> # cat test06.avi.md5
> 002bf7b936439242c8b8c85a3d37a5de  test06.avi

Ouch.
Suspect your hardware: memory, CPU, disk.
Could the system be too hot?
Is the CPU over-clocked?
Let memtest run overnight.

If you have enough space on a memory-backed file system
(usually /dev/shm), copy the file to it first and repeat the experiment.
That should eliminate the possibility of disk read errors.