I have two optical drives (not SATA) that previously showed up as /dev/hda and /dev/hdb. No longer. I see no mention of them in fstab and catting all the /dev/dvd /dev/cd... /dev/sr.. turns up nothing.
If I place a disk with info in the drive nothing appears anywhere I can see (not in dmesg).

K3b tells me no devices found.
wodim tells me Detected CD-R drive: /dev/sr1
wodim: Cannot do inquiry for CD/DVD-Recorder.
Errno: 5 (Input/output error), test unit ready scsi sendcmd: fatal error
CDB: 00 00 00 00 00 00
cmd finished after 0.000s timeout 40s

(These are not SATA drives.)

?

My apologies. I rebooted and everything was fine.

Actually, if I reboot without cd's in the drives then the drives aren't accessible again. How can I fix this (without having to boot with CDs in the drives)?