Guest nessus13 Posted April 28, 2003 Report Share Posted April 28, 2003 I downloaded the mdk 9.1 images from the mirrors posted on their site and did checksum on the iso's once they were downloaded. No problems there. I burned a copy onto a cd and did a checksum on the cd. Wrong checksum. So, thinking there was a burning error, I burned another copy. Same problem, even the same incorrect checksum. Anybody have any idea why this would happen? David Quote Link to comment Share on other sites More sharing options...
MottS Posted April 29, 2003 Report Share Posted April 29, 2003 This is normal. It depends of the method you burned the cd (DAO, TAO, ..). Me and ramfree17 wrote something in the FAQ about that. In our research, we were supprised to learn that the cd checksum will depend of the method you actually burn the cd. Here is the link to the FAQ (look in the references for further details): http://www.mandrakeusers.org/viewtopic.php?t=4638 Hope this helps MOttS Quote Link to comment Share on other sites More sharing options...
pmpatrick Posted April 29, 2003 Report Share Posted April 29, 2003 Here's another link on md5sums of CDs: http://www.troubleshooters.com/linux/coasterless.htm From my reading of the above, using something like this: cat /dev/hdx | md5sum can give false negatives for CDs. The script contained in the article should correct this problem. Quote Link to comment Share on other sites More sharing options...
ramfree17 Posted April 29, 2003 Report Share Posted April 29, 2003 Here's another link on md5sums of CDs: http://www.troubleshooters.com/linux/coasterless.htm its already in the reference links of the FAQ, but thanks for the additional note. if its not in there yet we (right motts? ;) ) will add it. ciao! Quote Link to comment Share on other sites More sharing options...
MottS Posted April 29, 2003 Report Share Posted April 29, 2003 its already in the reference links of the FAQ, but thanks for the additional note. if its not in there yet we (right motts? ;) ) will add it. It's there :shock: Did you add it or it was already there? .. whatever .. MottS Quote Link to comment Share on other sites More sharing options...
Guest nessus13 Posted April 29, 2003 Report Share Posted April 29, 2003 Thanks everybody! I'm still having trouble with my checksums, but I've learned a whole lot. David Quote Link to comment Share on other sites More sharing options...
Guest ndeb Posted April 30, 2003 Report Share Posted April 30, 2003 The real reason why check summing a CD is harder than checksumming an ISO on a hard-drive is given in https://listman.redhat.com/pipermail/seawol...ril/000378.html . Run the command isoinfo -d -i /dev/cdrom , assuming that /dev/cdrom is the device name of the cd drive. Look for these entries in the ouput Logical block size is: 2048 Volume size is: 355632 and note the numbers. Now run this command: dd if=/dev/cdrom bs=2048 count=355632 conv=notrunc,noerror | md5sum Quote Link to comment Share on other sites More sharing options...
MottS Posted April 30, 2003 Report Share Posted April 30, 2003 Well, this solution looks great but does not work on my system. Here is some output gd@localhost gd $ md5sum /dev/scsi/host0/bus0/target0/lun0/cd md5sum: /dev/scsi/host0/bus0/target0/lun0/cd: Input/output error gd@localhost gd $ dd if=/dev/scsi/host0/bus0/target0/lun0/cd | md5sum dd: reading `/dev/scsi/host0/bus0/target0/lun0/cd': Input/output error 1332256+0 records in 1332256+0 records out e370ab902cef2b0d2e8a8955aded13c4 - gd@localhost gd $ df --block-size=2048 /dev/scsi/host0/bus0/target0/lun0/cd Filesystem 2K-blocks Used Available Use% Mounted on /dev/scsi/host0/bus0/target0/lun0/cd 333088 333088 0 100% /mnt/DVD gd@localhost gd $ dd if=/dev/scsi/host0/bus0/target0/lun0/cd bs=2048 count=333088 | md5sum dd: reading `/dev/scsi/host0/bus0/target0/lun0/cd': Input/output error 333038+0 records in 333038+0 records out 93abcd6b79f69a3963ee251feea9f104 - gd@localhost gd $ umount /mnt/DVD/ gd@localhost gd $ dd if=/dev/scsi/host0/bus0/target0/lun0/cd bs=2048 count=333088 | md5sum dd: reading `/dev/scsi/host0/bus0/target0/lun0/cd': Input/output error 333064+0 records in 333064+0 records out e370ab902cef2b0d2e8a8955aded13c4 - The original md5sum is 6f1581974e12420fef87868ed6caa31f Could someone make a test? MOtts Quote Link to comment Share on other sites More sharing options...
Guest nessus13 Posted April 30, 2003 Report Share Posted April 30, 2003 MOTTs, I was getting the same thing you were. It gave me a different checksum when I used the dd command and specified the blocksize and number of blocks. Sorry, no code, as I'm away from my linux box. David Quote Link to comment Share on other sites More sharing options...
Guest ndeb Posted April 30, 2003 Report Share Posted April 30, 2003 6f1581974e12420fef87868ed6caa31f Mandrake91-cd1-inst.i586.iso 87afe11ddef6b619866322aa0797e45f Mandrake91-cd2-ext.i586.iso ff187c7a552722f42790b5726fdb62b3 Mandrake91-cd3-i18n.i586.iso Quote Link to comment Share on other sites More sharing options...
pmpatrick Posted April 30, 2003 Report Share Posted April 30, 2003 ndeb wrote: dd if=/dev/cdrom bs=2048 count=355632 conv=notrunc,noerror | md5sum Motts ran: gd@localhost gd $ dd if=/dev/scsi/host0/bus0/target0/lun0/cd bs=2048 count=333088 | md5sum I think the missing "conv=notrunc,noerror" explains the discrepancy as evidenced by the Input/Output error on the next line of Motts' code, i.e. a CD read error.l I think ndeb's way is correct because I get the identical results when using the rawread script referenced in the link on my prior post. The script just automates ndeb's procedure. Here's my output for CD1: [patrick@localhost cd_md5sums]$ sh rawread /dev/cdrom | md5sum dd if=/dev/cdrom bs=2048 count=333088 conv=notrunc,noerror 333088+0 records in 333088+0 records out 6f1581974e12420fef87868ed6caa31f - The point of the referenced article was that you can get read errors and erroneous md5sums when checking CDs if you don't use the dd command with the appropriate isoinfo. Apparently, the " conv=notrunc,noerror" is critical in eliminating those read errors. I don't pretend to understand why, but it does seem to be the case. Quote Link to comment Share on other sites More sharing options...
MottS Posted April 30, 2003 Report Share Posted April 30, 2003 I'm gonna run it again at home I promess MottS Quote Link to comment Share on other sites More sharing options...
MottS Posted May 1, 2003 Report Share Posted May 1, 2003 Well, I guess I'm not lucky but I'm still not getting the right md5sum although I installed succesfully MDK 9.1 2 times with that cd. Look at that: gd@localhost gd $ isoinfo -d -i /dev/cdrom CD-ROM is in ISO 9660 format System id: LINUX Volume id: MandrakeLinux9.1-Download-1 Volume set id: 91DOWNLOAD1 Publisher id: Mandrakesoft Data preparer id: Application id: Installation CD 1 (x86) Copyright File id: Abstract File id: Bibliographic File id: Volume set size is: 1 Volume set sequence number is: 1 Logical block size is: 2048 Volume size is: 333088 Joliet with UCS level 3 found Rock Ridge signatures version 1 found gd@localhost gd $ dd if=/dev/cdrom bs=2048 count=333088 conv=notrunc,noerror | md5sum dd: reading `/dev/cdrom': Input/output error 333052+0 records in 333052+0 records out dd: reading `/dev/cdrom': Input/output error 333053+0 records in 333053+0 records out dd: reading `/dev/cdrom': Input/output error 333054+0 records in 333054+0 records out dd: reading `/dev/cdrom': Input/output error 333055+0 records in 333055+0 records out dd: reading `/dev/cdrom': Input/output error 333056+0 records in 333056+0 records out dd: reading `/dev/cdrom': Input/output error 333057+0 records in 333057+0 records out dd: reading `/dev/cdrom': Input/output error 333058+0 records in 333058+0 records out dd: reading `/dev/cdrom': Input/output error 333059+0 records in 333059+0 records out dd: reading `/dev/cdrom': Input/output error 333060+0 records in 333060+0 records out dd: reading `/dev/cdrom': Input/output error 333061+0 records in 333061+0 records out dd: reading `/dev/cdrom': Input/output error 333062+0 records in 333062+0 records out dd: reading `/dev/cdrom': Input/output error 333063+0 records in 333063+0 records out dd: reading `/dev/cdrom': Input/output error 333064+0 records in 333064+0 records out dd: reading `/dev/cdrom': Input/output error 333065+0 records in 333065+0 records out dd: reading `/dev/cdrom': Input/output error 333066+0 records in 333066+0 records out dd: reading `/dev/cdrom': Input/output error 333067+0 records in 333067+0 records out dd: reading `/dev/cdrom': Input/output error 333068+0 records in 333068+0 records out dd: reading `/dev/cdrom': Input/output error 333069+0 records in 333069+0 records out dd: reading `/dev/cdrom': Input/output error 333070+0 records in 333070+0 records out dd: reading `/dev/cdrom': Input/output error 333070+0 records in 333070+0 records out 333070+0 records in 333070+0 records out da61eff279644ae6d631e53b34ee05ed - gd@localhost gd $ su Password: root@localhost gd # isoinfo -d -i /dev/cdrom CD-ROM is in ISO 9660 format System id: LINUX Volume id: MandrakeLinux9.1-Download-1 Volume set id: 91DOWNLOAD1 Publisher id: Mandrakesoft Data preparer id: Application id: Installation CD 1 (x86) Copyright File id: Abstract File id: Bibliographic File id: Volume set size is: 1 Volume set sequence number is: 1 Logical block size is: 2048 Volume size is: 333088 Joliet with UCS level 3 found Rock Ridge signatures version 1 found root@localhost gd # dd if=/dev/cdrom bs=2048 count=333088 conv=notrunc,noerror | md5sum dd: reading `/dev/cdrom': Input/output error 333044+0 records in 333044+0 records out dd: reading `/dev/cdrom': Input/output error 333045+0 records in 333045+0 records out dd: reading `/dev/cdrom': Input/output error 333046+0 records in 333046+0 records out dd: reading `/dev/cdrom': Input/output error 333047+0 records in 333047+0 records out dd: reading `/dev/cdrom': Input/output error 333048+0 records in 333048+0 records out dd: reading `/dev/cdrom': Input/output error 333049+0 records in 333049+0 records out dd: reading `/dev/cdrom': Input/output error 333050+0 records in 333050+0 records out dd: reading `/dev/cdrom': Input/output error 333051+0 records in 333051+0 records out dd: reading `/dev/cdrom': Input/output error 333052+0 records in 333052+0 records out dd: reading `/dev/cdrom': Input/output error 333053+0 records in 333053+0 records out dd: reading `/dev/cdrom': Input/output error 333054+0 records in 333054+0 records out dd: reading `/dev/cdrom': Input/output error 333055+0 records in 333055+0 records out dd: reading `/dev/cdrom': Input/output error 333056+0 records in 333056+0 records out dd: reading `/dev/cdrom': Input/output error 333057+0 records in 333057+0 records out dd: reading `/dev/cdrom': Input/output error 333058+0 records in 333058+0 records out dd: reading `/dev/cdrom': Input/output error 333059+0 records in 333059+0 records out dd: reading `/dev/cdrom': Input/output error 333060+0 records in 333060+0 records out dd: reading `/dev/cdrom': Input/output error 333061+0 records in 333061+0 records out dd: reading `/dev/cdrom': Input/output error 333062+0 records in 333062+0 records out dd: reading `/dev/cdrom': Input/output error 333063+0 records in 333063+0 records out dd: reading `/dev/cdrom': Input/output error 333064+0 records in 333064+0 records out dd: reading `/dev/cdrom': Input/output error 333065+0 records in 333065+0 records out dd: reading `/dev/cdrom': Input/output error 333066+0 records in 333066+0 records out dd: reading `/dev/cdrom': Input/output error 333066+0 records in 333066+0 records out 333066+0 records in 333066+0 records out 697086e4646bb4c622be0e0a9bbec324 - WTF :!: Quote Link to comment Share on other sites More sharing options...
pmpatrick Posted May 1, 2003 Report Share Posted May 1, 2003 Holy sh*t!!!! Maybe it's something in the way dd reads your cdrom. If you have a commercial data cd (i.e. not a CD-R) you could try that and see if you still get read errors. Quote Link to comment Share on other sites More sharing options...
Guest ndeb Posted May 1, 2003 Report Share Posted May 1, 2003 MottS, Do u have more than 1 CD drive ? U have to use the correct cd drive name. Quote Link to comment Share on other sites More sharing options...
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