Gentoo Linux
From Robertjd
hd now sd
According to this post, since kernel 2.6.20 the system will use libATA drivers for all drives which will result in drives loading up as /dev/sda instead of /dev/hda (even if they are IDE drives):
http://www.linuxquestions.org/questions/arch-29/why-sda-and-not-hda-552872/
This confused me because the gentoo minimal installer CD creates the installer environment using the older drivers and loads drives into /dev/hda etc. So I configured grub and fstab for hda names and got a kernel panic on reboot because the installed system loaded drives to sda. Switching grub and fstab to use sda names fixed the problem.