Can someone tell me if I am approaching this wrong? I created .iso images of all of the original SuSE 9.1 Pro CDs and DVDs. Now I am wanting to compare the MD5 checksums for the CDs with that of the iso images. This worked great on the 1st 2 CDs but has gone south since. I am using the command: md5sum /dev/cdrom The odd thing is when I started getting odd readings, I ran the sum 3 times consecutively on the same CD and got 3 different values: :~$ md5sum /dev/cdrom 38e72a5efd89851ceb7349d7406ac035 /dev/cdrom :~$ md5sum /dev/cdrom 31dea26a1f7e5fd2c4f8a384c1bef8e0 /dev/cdrom ~$ md5sum /dev/cdrom 9c1e9e02ecd5401c87ac2ca59c69ee92 /dev/cdrom Shouldn't I get the same value each time? Am I misunderstanding the MD5 sums? TIA, Darrell Cormier
Can someone tell me if I am approaching this wrong?
I created .iso images of all of the original SuSE 9.1 Pro CDs and DVDs. Now I am wanting to compare the MD5 checksums for the CDs with that of the iso images. This worked great on the 1st 2 CDs but has gone south since.
I am using the command:
md5sum /dev/cdrom
The odd thing is when I started getting odd readings, I ran the sum 3 times consecutively on the same CD and got 3 different values: :~$ md5sum /dev/cdrom 38e72a5efd89851ceb7349d7406ac035 /dev/cdrom :~$ md5sum /dev/cdrom 31dea26a1f7e5fd2c4f8a384c1bef8e0 /dev/cdrom ~$ md5sum /dev/cdrom 9c1e9e02ecd5401c87ac2ca59c69ee92 /dev/cdrom
Shouldn't I get the same value each time? Am I misunderstanding the MD5 sums?
Your right, something is wrong. ===> More than you wanted to know below ;-) One thing you might try is: dd if=/dev/cdrom | md5sum That way dd can tell you how many blocks of data it is reading and you can confirm the whole cd is being read each time. Finally, it you are really curious you can install dcfldd and use it to show the md5sum for each chunk of the cd. dcfldd == DOD Computer Forensics Labs DD I think the command would be dcfldd if=/dev/cdrom of=/dev/null hashwindow=1M hashlog=/tmp/cdrom.hashlog You could run that a couple of times, then diff the hashlogs to see which part of the cdrom is flackey. one place to find dcfldd is http://sourceforge.net/project/showfiles.php?group_id=46038 Hope that was interesting if nothing else. :) Greg -- Greg Freemyer
Greg Freemyer wrote:
Shouldn't I get the same value each time? Am I misunderstanding the MD5 sums?
Your right, something is wrong.
===> More than you wanted to know below ;-)
One thing you might try is:
dd if=/dev/cdrom | md5sum
Greg
Thanks Greg, I did try your suggestion and it appears that my original CDs 3,4 and 5 have some problems. I at first thought I might be having drive problems but I have tried two different machines and 3 different rom drives with the same results. See below for sample md5 error output: dd if=/dev/cdrecorder | md5sum dd: reading `/dev/cdrecorder': Input/output error 1162800+0 records in 1162800+0 records out 0ed505701b0aa86ea208e0a8727e3591 - Therefore I am unsure if my .iso images are any good. I kept trying and eventually got what appear to be correct md5 checksums from the 9.1 Pro boxed media. I tried googling for the checksums, and I also searched the SuSE site, but came up empty. Can anyone verify these checksums for me? cd1 -- 017e6e625e1cecaf95c3c8ffc40fdf1c cd2 -- 91c5f44a6162bc5384b7f9968bd4fb4f cd3 -- 7db7efcf5986b88add217aefccc4daba cd4 -- 2bbb5a31596943ea174b58d8cd320ba7 cd5 -- 2e3af5434af4a63358ae1726e684359f DVD1a -- 6af511c68e068dad2478d66d7f098efb DVD1b-64 bit -- 30de4be400b099dd98c9e34281234ce1 DVD2a -- b1215d4ea2518149b34ce7ef3e22fb09 DVD2b-64 bit -- 86faa5a90d3b04fd0986652820136337 Thanks, Darrell Cormier
On Thu, Aug 26, 2004 at 03:53:05PM -0500, Darrell Cormier wrote:
Can someone tell me if I am approaching this wrong?
I am using the command:
md5sum /dev/cdrom
It might be reading wrong number of blocks from the device. Please see http://www.troubleshooters.com/linux/coasterless.htm for the details. Regards, -Kastus
participants (3)
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Darrell Cormier
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Greg Freemyer
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Kastus