How to recover the .iso file from a CD ?

I am sorry for this stupid question. I have tried Google for an hour, but lack of keywords failed to bring up any reasonable hint.

What I have done, is downloading KNOPPIX 5.1.1 and burnt it. It boots; everything okay. Now I need the .iso file back in order to share it. I think I read this before, but have a blackout. Of course, I could go through the whole process of remastering, but that's not what I want. Just insert the CD and extract bit by bit.
I have already tried on the level of bits and Bytes:
dd if=/dev/scd0 of=KNOPPIX.iso
cat /dev/scd0 > KNOPPIX.iso
730083328, 730148864 are the file sizes and none has the correct MD5-sum.

Thanks for any suggestion,

Uwe

you burnt the iso to a cd disk
you don't throw it away
you still have it
burn it again

or

take your working disk and make a copy of it
change the destination from your cd write to the file writing device (Nero)

Or, if you want someone else to be able to get it by a fie transfer, it's already being shared by hundreds by BitTorrent, have the person who wants a copy use that. While there is a way to make an iso from a CD, I'm certainly not going to encourage ayone to do that when the iso is otherwise available; there is too much chance that corruption could sneak in that way.

Thanks, I was sure I had read somewhere how to retrieve the ISO from that CD. :)

In any case, marhleet, I don't have it anymore, no. And not everywhere in the world is downloading so fast; on our campus no torrent is available.
Would have been good to have a simple and rather safe method.

Uwe

ok ...
you got the iso from somewhere fast
and burnt it
and now you aren't there

well, that's some more information

Nero burnt the iso to a cd
Nero can burn the cd to an iso
and you can MD5 check the iso file after
and you know where the md5 numbers are for where you got the iso originally
so burn away and check
and all should be happy happy

Quote:

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Nero can burn the cd to an iso

---

Fine, then. I didn't know Nero can do that.
Yahoo !!

I don't have any Nero. I did something like
cdrecord dev=1,1,0 KNOPPIX.iso
No chance then, I guess.

Have you tried

sudo dd if=/dev/hdc of=/mnt/hda1/knoppix.iso bs=2048

where /dev/hdc is your CDROM drive and /mnt/hda1 is the place where you wish to store the ISO file?