A note about old disc media that you might find valuable: there's a linux tool called "setcd" you can use to adjust the spin speed of your CDRom drive.

This is useful if you're recovering data from dodgy old discs; sometimes they become brittle over time and will burst at high rotation speeds. If you're using ten or twenty year old media, use "setcd -x 1" to dial the device down to as slow as it will go, then take an .iso image of the disk, loopmount it and work from that.

@mhoye I'd recommend using gnu ddrescue, which lets you stop and resume. This lets you recover using multiple attempts and drives.