Thank you. It was a 500mhz Dual USB. I've had it for about 4 years.
I was trying to upgrade the optical drive. The CD-ROM drive it came with would randomly eject, often during boot, but at other times as well. Zapping the PRAM would make the problem go away for awhile, but it would always come back. The drive would sometimes still read discs, but many times it would not. I've been using an external LaCie CD-RW drive connected via FireWire as a replacement, but I was getting annoyed by the internal CD-ROM drive randomly ejecting and I also wanted to add DVD playback capabilities to the iBook, so I searched eBay and found an internal DVD-ROM/CD-RW combo drive meant for iBooks for $15. I also wanted to remove the old mechanical internal HDD as well as I had moved on to using an external SSD as my boot drive.