i had a plan to back up some important files, unfortunately the disc made a note of the date Jan 31 2012 but decided to leave out the files attempting to backup then mistaking that disc as a dvd rw i kept trying to burn it on again, this of course was my mistake, reading it wrong. but the first part i still don't get why it happened. anyone have the science behind dropping files onto a dvd r? and at what stage is the process irreversible?