Re: Jaunty Jackalope (RESOLVED)

On 11/02/2009 07:49 PM, Rashkae wrote:
> NoOp wrote:
...
>> And I've just now proven myself wrong :-( The md5sum of the CD matches
>> that of the iso. So apologies to the list, and to John Graddy. I'll
>> still see if I can find the thread tomorrow, but mea culpa & apologies
>> to all.
>
> You're comparing the md5sum from a file to that of a CD. They will
> sometimes not match because the lead out from writing to a cd appends
> some nulls. It seems to depend on type of drive and exact command used
> to burn cd, but either way, you cannot reliably compare md5sum of an iso
> with the cdrom dev device.
Ah, that's it. I still can't find the thread we this was discussed, but
this article might suffice instead :-)

Rather, use isoinfo command to get the
> exactly number of bytes, and use dd to pipe that from the cd to md5sum
>
> Example: isodinfo -d -i /dev/cdrom will in the output, include a
> 'Volume size' number. For example, say it's 1000
>
> dd if=/dev/dvd bs=2048 count=1000 | md5sum -
>
> That md5sum should always match the iso file that was used to burn the cd.
>
> None of this matters in John's case, however, since all he did was copy
> the file from one hard drive to another, in which case, the md5sum
> should absofuckinglutely not change. Either the thumb drive is
> defective, or one the pc's has bad ram, or is corrupting data in the IO
> path.
Yep. I was thinking about the CD issue (must have been a full moon out
last night).
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