Hi, 01.11.2007 16:43,, Hydro Meteor wrote:: > Hello all -- > > I'm not sure how many others have run into this problem, but according > to the Bacula User's Guide, there are two ways to "blank" an unformatted > (fresh from the spindle) DVD disc (in my case I'm using / testing DVD+RW > discs): > > 1.) Not the entire disc: > > # dd if=/dev/zero bs=1024 count=512 | growisofs -Z /dev/xxx=/dev/fd/0 > > > > 2.) The entire disc: > > # growisofs -Z /dev/xxx=/dev/zero > > ... > Getting back the aforementioned, what I find a bit strange however is > that partially blanking a new DVD+RW out of the box yields error for me, > as in (where /dev/cdrom is how Debian, as standard practice, see the > mapped SuperDrive on the Xserve): ... > However, if I formatted an entire DVD+RW disc, I had no problems getting > the Storage Daemon to complete a backup job writing to the fully blanked > DVD.
Oh god... that is a really difficult question, I think. When I was working on the dvd-handler script, I tried lots of things. What you see dvd-handler doing is, basically, what I found worked for me. I worked with - if I recall correctly - three different DVD writer drives, DVD+R, DVD-R, DVD+RW, and DVD-RW. I juggled dozens of different disk around, and managed to make some unusable, some unreadable by some, but not all my, DVD drives, and so on. I also read lots and lots of stuff on DVD formats, the differences between + and - media, the different ways of formatting, and so on. In the end, I didn't understand anything :-) , read through my notes, and implemented what worked in most of my test cases. For example, I found that to effectively blank a DVD for use in one drive, I needed a minimum size of data overwritten, while other drives (or the drivers handling them) accepted a disk as empty when only the first few sectors were blanked. > Question: how do DVD disc media vendors (TDK, Verbatim, et al) ship DVD > media? I have no idea :-) There is a difference between an unsed disk and a blanked or a formatted one. I don't recall the details now, but "Restricted Overwrite" was one example of how you can handle the same type of media in different ways... > I presume that they do not fill the bits on their DVDs with ASCII > NULL characters (which is what happens when utilizing the /dev/zero > device), true? I guess you're right there. The actual disk contents is probably simply invalid to all the interpretation layers above physical. If you want to know more, you might try to use the dvd-handler test command - I believe it reports an excerpt of the actual disk status. Naturally, dvd+rw-mediainfo, which is used by dvd-handler, has much more information to print. Good luck! Arno -- Arno Lehmann IT-Service Lehmann www.its-lehmann.de ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
