Puppy Linux Discussion Forum

[kethd]

There are many ways to make an iso file from a CD, using dd or even just cat. Sometimes these work. Sometimes they do not.

Graveman can be used to do this, but sometimes it fails with peculiar, frustrating errors.

The best way I have found so far is from the command line:
# readcd -v dev=ATAPI:/dev/hdc f=cd.iso
which offers good running commentary about progress and any errors encountered.

Before doing this, you might want to do:
# isoinfo -d -i /dev/hdc
which will tell you the blocksize (usually 2048 for CDs) and the record count (volume size).

If you make a perfect, standard iso file from a CD (like Puppy 1.0.8r1), you can then use md5sum to make sure that your iso file is identical to the original official iso file. This is a way to make sure that your CD is perfect. And a way to make sure that you have a good iso file, for burning more copies.

I used 1.0.8r1 to make an iso file and then burn a copy of itself with Burniso2cd. The burn seemed to go OK, but then there were weird problems. When I tried to make an iso file from the copy, graveman complained right at the end. When I tried various ways of reading the CD, sometimes it read OK, sometimes problems at the end. It seems to boot OK -- the problem seems to be with some trailer blocks at the end.

Isoinfo says the record count is 31582, which seems correct for 108r1. dd and cat sometimes only get 31580 recs, and then md5sum does not match. But readcd thinks there are 31584 recs, and then fails when it tries to read off the end.

It would be nice if there were some super-CD-inspect tool, that could tell you in absurd detail exactly what is on the CD, what problems are where, and what could cause that.

I did the burn with a new NEC ND-3550A DVD burner. Now I don't know if the problem was the burner, or using 1.0.8r1, or just bad luck.

[kethd]

For further tech discussion, see:
http://www.murga.org/%7Epuppy/viewtopic.php?t=6915
CD Burn Glitch - two extra sectors

[Lobster]

http://www.petri.co.il/how_to_write_iso_files_to_cd.htm