UUIDs missing in Ubuntu?

[Sean Crago]

I recently did a benign looking apt-get dist-upgrade in Ubuntu
Intrepid Ibex and, a few days later, rebooted. I think a kernel patch
was involved, but I'm not sure/haven't tried to revert to an old one
yet to fix this problem, but I'd like to find a cleaner fix:

I have one old PATA HDD on my box that I mount on boot to /tmp via a
UUID-based fstab entry. This used to work just fine. It's mounted a
generic SCSI device, so it doesn't show up as hda1 anymore, but it
shows up as sda1 and is symlinked to in /dev/disk/*/, as are my other
generic SCSI devices - My removable media, my memory card reader, etc.
Now, though, I don't see anything except my one SATA drive in my
/dev/disk/by-*/ entries.

To make things substantially MORE strange, all of these problems went
away at 13:37 this afternoon, when the missing symlinks were created
en masse. No reference at all exists to that time in any plaintext
file in /var/log/

Any guesses as to what's wrong with my system and how to prevent this
from blocking a proper UUID-based fstab from working at boot time?

Thanks,
Sean Crago
Kathmandu