Apologies if this is the wrong component, I was not sure where to file it. If the line for the root filesystem is missing in /etc/fstab then bootup will fail apparently due to fsck being passed "/" as an argument rather than a device. This prints an uber-scary message about the superblock being toasted and drops you into a recovery console. I have no clue how my machine got into the state where it was missing this entry. I did an an unclean shutdown but it's a rather odd "corruption" to get :)
If you look at /proc/mounts, you'll have: [notting@nostromo: ~]$ cat /proc/mounts ... /dev/root / ext3 rw,noatime 0 0 ... Hence, it's a bit more code to dig out the root device name. Probably won't fix this at this point.