"Thomas Schmitt" <[EMAIL PROTECTED]> wrote: > 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
Wrong: If the media was written in the default (reliable) sequential mode, you only need to call cdrecord blank=fast A full blank is only needed if the media was written in packet mode before or if it was formatted. > On occasion of anniversary of libburn revival let me state Well, cdrecord will soon have it's 10th DVD writing anniversary ;-) > Blanking but not formatting can be done with cdrecord and wodim > cdrecord -v dev=ATA:1,0,0 blank=all This is not needed..... cdrecord usually works without dev= parameter. If you need it because you have more than one drive, dev=ATA:1,0,0 will not work. Then you should call cdrecord -scanbus and the most possible parameter is dev=1000,0,0 > wodim -v dev=/dev/hdc blank=all Let me not comment non-free software... > > 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. It is most unlikely that dvd+rw-format -blank=full does the same as cdrecord blank=fast. This would be counter-intuitive. > > 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) DVD-RWs last a very long time if you use the right software, e.g. cdrecord. > 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. Formatting DVD-RWs will take them into a less reliable mode. > 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. DVD-RWs are very reliable. DVD+RW is a mess, I found no drive that realiably reads DVD+RWs written by drives from another brand. Be sure to prefer cdrecord blank=fast over cdrecord blank=all Jörg -- EMail:[EMAIL PROTECTED] (home) Jörg Schilling D-13353 Berlin [EMAIL PROTECTED] (uni) [EMAIL PROTECTED] (work) Blog: http://schily.blogspot.com/ URL: http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]