Checking the md5sum of a burned CD
I've burned a CD from a .iso image. Now I want to verify the burning process worked correctly (there were no errors reported). Note, I verified the md5sums of the .iso's before I burned them. So now I'd like to check the burned CD against that md5sum. Thanks, Mike -- Old programmers never die; they just branch to a new address. 04:30:01 up 1:11, 2 users, load average: 1.08, 0.68, 0.49 Linux Registered User #241685 http://counter.li.org -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: Checking the md5sum of a burned CD
thveillon.debian wrote: M. Lewis a écrit : I've burned a CD from a .iso image. Now I want to verify the burning process worked correctly (there were no errors reported). Note, I verified the md5sums of the .iso's before I burned them. So now I'd like to check the burned CD against that md5sum. Thanks, Mike Hi, md5sum /dev/cdrom or md5sum /dev/scd0 works here (Squeeze and Lenny), whatever applies to your system. If you have I/O error check that it's not mounted, and not accessed by some other process (like kio* in KDE). Tom Great. Thanks Tom. I was totally unaware it could be done as simply as that. Mike -- IBM: Install Bigger Memory 05:25:01 up 2:06, 2 users, load average: 1.43, 1.55, 1.15 Linux Registered User #241685 http://counter.li.org -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: Checking the md5sum of a burned CD
M. Lewis a écrit : I've burned a CD from a .iso image. Now I want to verify the burning process worked correctly (there were no errors reported). Note, I verified the md5sums of the .iso's before I burned them. So now I'd like to check the burned CD against that md5sum. Thanks, Mike Hi, md5sum /dev/cdrom or md5sum /dev/scd0 works here (Squeeze and Lenny), whatever applies to your system. If you have I/O error check that it's not mounted, and not accessed by some other process (like kio* in KDE). Tom -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: Checking the md5sum of a burned CD
On 2009-03-19_05:29:17, M. Lewis wrote: thveillon.debian wrote: M. Lewis a ??crit : I've burned a CD from a .iso image. Now I want to verify the burning process worked correctly (there were no errors reported). Note, I verified the md5sums of the .iso's before I burned them. So now I'd like to check the burned CD against that md5sum. Thanks, Mike Hi, md5sum /dev/cdrom or md5sum /dev/scd0 works here (Squeeze and Lenny), whatever applies to your system. If you have I/O error check that it's not mounted, and not accessed by some other process (like kio* in KDE). Tom Great. Thanks Tom. I was totally unaware it could be done as simply as that. Several months ago, when Lenny was still 'testing', I had difficulty with this: On my hardware, the read from /dev/cdrom had extra bytes at the end and was a longer byte stream than the .iso image from which the CD was burned. So, of course, compare of md5 sums between CD and .iso failed. There is a work-around in that one can use dd to copy from /dev/cdrom just enough blocks to match the length of the .iso file, and then compute the md5sum of that (truncated) length matching file. OTOH the problem may not have been hardware, and it may have been fixed. So if at first you get results that indicate that you have a badly burned CD, it may be the test that is bad, not the burn. I have not verified this situation recently, so this is just a warning. I think there are many people like me who know about this old problem, so it would be nice for you to report back to the list as to whether or not it is still there. -- Paul E Condon pecon...@mesanetworks.net -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: Checking the md5sum of a burned CD
On Thu, 19 Mar 2009 04:33:09 -0500, M. Lewis wrote: I've burned a CD from a .iso image. Now I want to verify the burning process worked correctly (there were no errors reported). Note, I verified the md5sums of the .iso's before I burned them. So now I'd like to check the burned CD against that md5sum. The best approach for checking burned CDs, which is what Red Hat used, is implanting a MD5 checksum to it by implantisomd5, and verify later with checkisomd5. So the CD itself and checkisomd is all you need to verify it, even after several years, and you've forgot where you put its original md5sum. The implantisomd5 and checkisomd5 are available in Debian (later) as the isomd5sum package. -- Tong (remove underscore(s) to reply) http://xpt.sourceforge.net/techdocs/ http://xpt.sourceforge.net/tools/ -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: Checking the md5sum of a burned CD
On 2009-03-19_15:39:56, T o n g wrote: On Thu, 19 Mar 2009 04:33:09 -0500, M. Lewis wrote: I've burned a CD from a .iso image. Now I want to verify the burning process worked correctly (there were no errors reported). Note, I verified the md5sums of the .iso's before I burned them. So now I'd like to check the burned CD against that md5sum. The best approach for checking burned CDs, which is what Red Hat used, is implanting a MD5 checksum to it by implantisomd5, and verify later with checkisomd5. So the CD itself and checkisomd is all you need to verify it, even after several years, and you've forgot where you put its original md5sum. The implantisomd5 and checkisomd5 are available in Debian (later) as the isomd5sum package. I think you are misunderstanding the situation, or perhaps, I misunderstand what you intend to say. Computing a checksum, does not, by itself, verify the correctness of the CD. You must have knowledge of what the md5sum of the original .iso was, and you must get that same md5sum value from running the program 'md5sum' on the CD. Of course, if you can't even read the CD into the md5sum program, then it is surely a bad CD. Can you mount the CD, and examine its contents? If you cannot, then producing an md5sum for it is pointless. If you can mount it, there may be, somewhere on it, a record of what its md5sum should be. But an md5sum of a CD, alone, is useless. -- Paul E Condon pecon...@mesanetworks.net -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: Checking the md5sum of a burned CD
Paul E Condon wrote : On 2009-03-19_05:29:17, M. Lewis wrote: thveillon.debian wrote: M. Lewis a ??crit : I've burned a CD from a .iso image. Now I want to verify the burning process worked correctly (there were no errors reported). Note, I verified the md5sums of the .iso's before I burned them. So now I'd like to check the burned CD against that md5sum. Thanks, Mike Hi, md5sum /dev/cdrom or md5sum /dev/scd0 works here (Squeeze and Lenny), whatever applies to your system. If you have I/O error check that it's not mounted, and not accessed by some other process (like kio* in KDE). Tom Great. Thanks Tom. I was totally unaware it could be done as simply as that. Several months ago, when Lenny was still 'testing', I had difficulty with this: On my hardware, the read from /dev/cdrom had extra bytes at the end and was a longer byte stream than the .iso image from which the CD was burned. So, of course, compare of md5 sums between CD and .iso failed. There is a work-around in that one can use dd to copy from /dev/cdrom just enough blocks to match the length of the .iso file, and then compute the md5sum of that (truncated) length matching file. OTOH the problem may not have been hardware, and it may have been fixed. So if at first you get results that indicate that you have a badly burned CD, it may be the test that is bad, not the burn. I have not verified this situation recently, so this is just a warning. I think there are many people like me who know about this old problem, so it would be nice for you to report back to the list as to whether or not it is still there. Following a similar thread on the French list where this problem was also related, I did some testing with dvd's and cd's, GNU-Linux distros and movies burnt with K3B, on Lenny almost stable and lately on Squeeze. I didn't come across any issue, so at least here it works fine. Tom -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: Checking the md5sum of a burned CD
On Thu, 19 Mar 2009 10:06:55 -0600, Paul E Condon wrote: So the CD itself and checkisomd is all you need to verify it, even after several years, and you've forgot where you put its original md5sum. . . I think you are misunderstanding the situation, or perhaps, I misunderstand what you intend to say. Computing a checksum, does not, by itself, verify the correctness of the CD. . . But an md5sum of a CD, alone, is useless. Maybe some more readings, if you care, can help change your thinking. - Do you know that on RedHat's cd boot menu, there is an entry to verify the integrity of CD? - Do you know how they did it? -- Tong (remove underscore(s) to reply) http://xpt.sourceforge.net/techdocs/ http://xpt.sourceforge.net/tools/ -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: Checking the md5sum of a burned CD
On 2009-03-19_16:33:50, T o n g wrote: On Thu, 19 Mar 2009 10:06:55 -0600, Paul E Condon wrote: So the CD itself and checkisomd is all you need to verify it, even after several years, and you've forgot where you put its original md5sum. . . I think you are misunderstanding the situation, or perhaps, I misunderstand what you intend to say. Computing a checksum, does not, by itself, verify the correctness of the CD. . . But an md5sum of a CD, alone, is useless. Maybe some more readings, if you care, can help change your thinking. - Do you know that on RedHat's cd boot menu, there is an entry to verify the integrity of CD? - Do you know how they did it? I think I will choose to believe that I misunderstood what you said. Peace. -- Paul E Condon pecon...@mesanetworks.net -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
RE: Checking the md5sum of a burned CD
-Original Message- From: M. Lewis [mailto:ca...@cajuninc.com] Sent: Thursday, March 19, 2009 3:33 AM To: debian-user@lists.debian.org Subject: Checking the md5sum of a burned CD I've burned a CD from a .iso image. Now I want to verify the burning process worked correctly (there were no errors reported). Note, I verified the md5sums of the .iso's before I burned them. So now I'd like to check the burned CD against that md5sum. Thanks, Mike -- Yo cannot use the same md5sum, because that md5sum is generated from the .iso file and you did not burn your CD as data CD contaning an .iso file. If so, your CD would not be bootable. But if you burned your CD as bootable CD there is no longer an .iso file and you will have to use md5sum.txt of your CD and check /every/ file inside your CD. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
