My poor abused laptop has a habit of loosing it's DVD drive on a regular basis, after a few drops too many. Normally I had simply rebooted after pushing back in the drive, but I was feeling like a dirty windows user with that method :)
As it turns out, Linux provides the answer. In Ubuntu, simply install "hotswap" using apt-get or your preferred method. To rescan for IDE devices run the following command:
sudo hotswap -c 1 rescan-ide
Ignore the errors and simply enjoy your DVD :)
