Hi, > I'm trying to "blank" / "zero out" / "nullify" a dvd-rw that has > previously had data written to it, so that I can give that dvd-rw to > someone else and they wont see the data. (NB I'm _not_ worried about > "magnetic/optical history", the FBI, the CIA etc). > Please note that I DO NOT necessarily want to turn the disk back to > the way it was when it was still in its plastic wrapper. > ... > ~# growisofs -Z /dev/hdc=/dev/zero > ... > :-[ [EMAIL PROTECTED] failed with SK=5h/ASC=30h/ACQ=05h]: Wrong medium type > :-( media is not formatted or unsupported. > :-( write failed: Wrong medium type > ... > ~$ dvd+rw-mediainfo > ... > Mounted Media: 14h, DVD-RW Sequential
You got a sequentially written DVD-RW. Before you can overwrite its content it needs to be blanked dvd+rw-format -blank=full /dev/hdc or formatted dvd+rw-format -force /dev/hdc On occasion of anniversary of libburn revival let me state that the equivalent cdrskin commands would be cdrskin -v dev=/dev/hdc blank=deformat_sequential resp. cdrskin -v dev=/dev/hdc blank=format_overwrite Blanking but not formatting can be done with cdrecord and wodim cdrecord -v dev=ATA:1,0,0 blank=all wodim -v dev=/dev/hdc blank=all If you use blank=fast then the media will not be useable for /dev/zero as data source unless you specify an image size. (I never tried growisofs -use-the-force-luke=tracksize:<number>) > But (and this is the strange part), if I format the disk using > "dvd+rw-format -blank=full /dev/hdc" (which works), then "growisofs -Z > /dev/hdc=/dev/zero" works perfectly THE FIRST TIME - it only fails the > second time I try to do it. That's because unformatted DVD-RW are much like CD-RW. You can write a session to them, leave them open, append another session, and so on. But you can re-use them only after blanking. dvd+rw-format -blank=full brings a DVD-RW into this unformatted state. -blank without "=full" does the same as cdrecord blank=fast. You seem to expect the media to behave like DVD+RW. So format it once. dvd+rw-format /dev/hdc -force should not be needed because it is not formatted. But i never tried without -force. > is there a way to "blank" / "zero out" / "nullify" > a dvd-rw which won't permanently destroy the > disk if I do it 20 times? (start sarkasm) To my experience, most DVD-RW are destroyed before they get into their shrink wrap. (end sarkasm) Formatting is needed only once. The media stays overwriteable until you deformat it or it finally refuses to work with your drive. So there is no problem with 20 times or so. Blanking (i.e. deformatting) seems not to be more dangerous to the media than overwriting with data. This way or that way the media will give up its life early enough. I got 3 DVD burners and none of them works well with 4x DVD-RW. For repeated backups i only use 4x DVD+RW. They get formatted automatically and blanking is not applicable to them. Have a nice day :) Thomas -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
