Hi, Richard Owlett wrote: > richard@jessie:~$ ls -l /media/richard/Lexar/dvd8_2.iso > -rw-r--r-- 1 richard richard 3976200192 Sep 9 07:36 > /media/richard/Lexar/dvd8_2.iso > > richard@jessie:~$ /sbin/isosize /media/richard/Lexar/dvd8_2.iso > 4677738496
You will need to get a new dvd8_2.iso of at least 4677738496 bytes size. > I've got some links "somewhere" for copying DVDs to files such that > checksums can be verified. Suspect that info may useful. Depending on the DVD medium type you have to expect trailing garbage after the end of the ISO. This has to be taken into respect when copying, diffing, or md5summing. I would use for copying from DVD to disk: blocks=$(expr $(/sbin/isosize /dev/sr0) / 2048) echo "Byte count: $(expr $blocks '*' 2048)" dd if=/dev/sr0 bs=2048 count=$blocks of=dvd8_2.iso (It would be nice if Debian's MD5SUMS would not only tell MD5 and image name but also the image size, or if there was a SIZES file.) Error messages from dd or dvd8_2.iso turning out smaller than the announced byte count indicate failure of copying. If the size is ok, compute the MD5 of dvd8_2.iso md5sum dvd8_2.iso If you have no checksum for the image, then eject and reload the medium and run dd if=/dev/sr0 bs=2048 count=$blocks | diff - dvd8_2.iso in order to detect instabilities with repeated copying. If so, then diff should report Binary files - and dvd8_2.iso differ -------------------------------------------------------------- If everything stays suspiciously silent, make a damage test. Before damaging the ISO, get the original state dd if=dvd8_2.iso bs=1 skip=30000 count=1 2>/dev/null | od -t x1 I get told 0000000 00 0000001 So byte 30000 has value 0. I replace it by a NewLine character (value 10): echo | dd conv=notrunc of=dvd8_2.iso bs=1 seek=30000 count=1 Now the above tests must report mismatch. Repair ISO: dd if=/dev/zero conv=notrunc of=dvd8_2.iso bs=1 seek=30000 count=1 If the original value was not 0, but hex "43": echo -n $'\0x43' | dd conv=notrunc of=dvd8_2.iso bs=1 seek=30000 count=1 Have a nice day :) Thomas
