No root file system is defined

On the weekend I was installing the new version of Mythbuntu (More interesting screenshots here) and I had a weird error, “No root file system is defined”. At first I thought it must have been something to do with failing to recognise the existing partitions or possibly they were corrupt. “fdisk -l” worked, returning sda, sda1-sda4, which was correct however “mount” would always fail. It turned out that it was just our old friend dmraid was breaking in new and unexpected ways. Here is how to worked around it:

Boot into live CD mode
Remove dmraid via Package Manager
Run Install Mythbuntu from the desktop shortcut

On multiple distributions and motherboards I consistently have problems with dmraid not finding/incorrectly identifying partitions/drives. I’m not the only one with these problems. I’m sure I am having these problems because I have raid hardware but am not using raid. Surely raid is an advanced enough feature that people with raid should be expected to know to install/add it? Perhaps the install could be attempted without raid support and the installer can say “Do you use raid?” or “Are these devices correct?” and at this point the installation restarts/redetects with dmraid enabled.

How To Automatically Download All of Your YouTube Favourites

FireFox add-ons such as 1-Click YouTube Video Download are good but one must visit every video and manually save it. I have a lot of favourites and I wanted to back them up with as little effort as possible. Here is how.

You will need youtube-dl. It is available via yum/apt-get however the version provided may be quite old (In Fedora 14 it did not support –playlist-start and –playlist-end).

Create a new playlist and add all the videos from your favourites (Note: A playlist can only contain 200 videos if you have more than than this you will have to make multiple playlists and repeat this process for each one).

Click on “Play All”. Copy the URL from the address bar for the first video when it tries to play (You only need this bit: “”).

Now tell youtube-dl to download the videos in the playlist:

python ./ --title --ignore-errors --playlist-start=1 --playlist-end=200

If you had more than 200 videos repeat this process for the ones that didn’t fit in the playlist.
This should work for other people’s playlists too.
You might want to make a note of the latest video in your favourites so that the next time you can backup only the new videos.
This process still requires some user interaction, if you find an even easier way where I can just say, “This is my user name, make it happen”, I’d love to know about it.