On 11/04/2013 04:21 PM, Yasha Karant wrote: > I need to do a media comparison between a data DVD and the .iso file > that purportedly contains the image of the exact DVD (including any > bootable or autoload binary files, not for an Intel instruction set > architecture). > > When burning to the DVD, applications such as K3B and Nero (for Linux) > will do a verify of the burned media. My understanding is that these > applications go through the device driver and device controller > hardware/firmware that may be applying error correction to the raw bit > stream; any such detected "hardware media" errors typically are reported > by the driver to a log file, but typically (if corrected) do not cause > the application to fail. > > If one mounts the .iso file, by a command similar to that below, > > # mount -t iso9660 -o ro,loop=/dev/loop0 /files/dvdimage.iso > /media1/virtualdisc > > and likewise has the physical DVD in the DVD drive and mounted from, > say, /dev/sr0 > > will a diff /dev/loop0 /dev/sr0 suffice? > > Is there a utility that will do the same thing that Nero would do as it > verifies after burning, but not requiring the burn -- that is, verify a > DVD against an ISO image file? > > If /dev/sr0 were mounted on, say, /media/someDVD, and the ISO image file on > /media1/virtualdisk , is there a utility or script to do a "bit by bit" > comparison via the mount points (not just the "raw" mount as /dev/sr0 )? > > Yasha Karant > Hi Yasha, Check the DVD as a raw device. After you burn the ISO, eject the DVD (clears out something, I don't know what, but had to learn the hard way): /usr/bin/eject /dev/sr0 Then inject the DVD (close the door). Can be on the same line. /usr/bin/eject -t /dev/sr0 Then make an MD5SUM of each md5sum /files/dvdimage.iso /dev/sr0 Eyeball the sums. One will be on top of the other. If you like, I have some leftover code I can send you. -T -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Computers are like air conditioners. They malfunction when you open windows ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~