What happens if you boot with the failsafe option?
Is it able to boot fully?
'knoppix failsafe'
I get to the first screen and then no matter what I do, it fails at "searching for CD of /dev/scd0" (or words to that effect).
Anyone got any idea why this might be happening?
What happens if you boot with the failsafe option?
Is it able to boot fully?
'knoppix failsafe'
Yup. I've tried that and also the no<whatever> options (all of them) to no effect.
The cursor flashes a few times next to the text and then freezes. The keyboard stop reacting around this time (i.e. I can't turn the Num-Lock on or off).
Is there a way of producing verbose screen output so I can tell at what point it's hanging?
You can try: 'knoppix 2' and see if you can sucessfully boot into text only mode.
If you can successfully do this, then type 'dmesg |more'
You can read through this and see if you see any error messages.
My suspicion however is that you have a bad .iso image.
You can try downloading the md5 file to check out the file size.
You may need to download a new iso (sigh).
I had the same problem with my first knoppix CD on some machines and not others. Based off a post that I found through google, I reburned the CD at a slower speed (8X instead of the CD-R's max capability of 40X). It fixed the problem when working with some CD-ROM drives.

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