[clug] md5sum and verifying DVD
Tony and Robyn Lewis
beakysnugger at yahoo.co.uk
Thu Jul 28 02:06:59 GMT 2005
Carlo Hamalainen wrote:
>c at t40:~$ md5sum 1.iso
>d7563e63f8e6306de0466cd3b3576571 1.iso
>
>c at t40:~$ md5sum /dev/hdc
>6b76ba56f97770f641012f156eba3a25 /dev/hdc
>
>Why are they different? What am I doing wrong here?
>
>
I suspect you'll find that it'll be reading trailing zeros/nuls/rubbish
at the end, which changes the MD5 hash.
There might be a prettier way, but try:
* finding the size of the ISO in bytes
* dd if=/dev/hdc | head --bytes=<size> | md5sum
I haven't tried this. You might find that the block sizes in dd defeat
you. If that's the case, and it's important enough to wait a long time,
try:
* dd if=/dev/hdc bs=1 | head --bytes=<size> | md5sum
This will read one byte at a time - a lot slower. There are probably
better ways...
Tony
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