thveillon.debian wrote: > Hugo Vanwoerkom a écrit : >> thveillon.debian wrote: >>> BALLABIO GERARDO a écrit : >>>> Hi all, >>>> I'd like to ask for suggestions on how to check a cd-rom (or dvd-rom) >>>> against the original iso image to verify that it has been burned >>>> correctly. >>>> >>>> I tried a couple of methods, but I am not sure that they work. >>>> >>>> One was to mount the iso via the loop device and compare the contents >>>> with "diff -qr". This can tell me that the files' contents are equal, >>>> but with bootable cd's, I'm not sure that it guarantees that the boot >>>> sector is recreated correctly. (Actually, this started from a real >>>> life experience where I burned a live-cd and it didn't boot.) >>>> >>>> The other was to copy back the cd-rom to disk with "dd if=/dev/hdb >>>> of=cdrom.iso". I assumed that by doing this, I would obtain an iso >>>> image identical to the original one; but to my surprise, I discovered >>>> that it was shorter by several kilobytes (exactly 156 512-bytes >>>> blocks, or 78 KiB). I verified that the two images are actually equal >>>> except for the missing bytes, and that those are all zeros. Is it >>>> always so? Can I assume that if I copy back a cd-rom with dd and then >>>> append 78 KiB of zeros, I'll always recover the original iso image? >>>> Or did I make some error and dd will, in fact, give me the >>>> untruncated iso if I do it the right way? >>>> >>>> Thank you. >>>> >>>> Gerardo >>>> >>>> >>> Hi, >>> >>> md5sum /path/to/isofile >>> >>> put cd/dvd in tray, then >>> >>> md5sum /dev/cdrom (or /dev/cdrom0... what applies to you). >>> >> >> That doesn't quite work out: >> >> mount /cdrom >> /Fri Oct 17-06:14:44HDC5# md5sum /cdrom >> md5sum: /cdrom: Is a directory >> >> or >> >> /home/hugo/gpc-qt4-002Fri Oct 17-06:14:16HDC5# md5sum /dev/hdd >> md5sum: /dev/hdd: Input/output error >> >> Hugo >> >> >> >> > Hi, > > >> put cd/dvd in tray, then > >> > >> md5sum /dev/cdrom (or /dev/cdrom0... what applies to you). > > works here : > > [EMAIL PROTECTED]:~$ md5sum > ~/Downloads/ISO/debian-LennyBeta2-amd64-netinst.iso > 83a907b1c150b9942c5048148b4d6892 > ~/Downloads/ISO/debian-LennyBeta2-amd64-netinst.iso > [EMAIL PROTECTED]:~$ md5sum /dev/cdrom > 83a907b1c150b9942c5048148b4d6892 /dev/cdrom > > > Tom > >
FYI: on some systems k3b is not checking at all when the drive is reloaded. Tip: disable the eject after burn option in k3b and voila. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
