Copying CDs

[Michael ODonnell]

>> Does anyone know how I can copy the whole CD as an ISO filesystem file?
>
>  Use the "readcd" program that comes with the cdrecord/mkisofs package.
>The syntax is (from memory, so double-check this):
>
>        readcd dev=/dev/sgfoo f=cdimage.iso
>
>where "sgfoo" is the SCSI generic device, and "cdimage.iso" is the output
>file.  The "dd" command may also work, but it can have trouble with CDs that
>use some of the more esoteric features of the CD standards.


IIRC, bootable CDs (El Torito spec) have a section on them
(not accessible by normal means) for what amounts to an
initrd - a little ramdisk that a CD-boot-capable BIOS is
obliged to load into memory and treat as the A: drive,
giving you a place to stand while you haul other stuff
off of the CD into memory.  I'm pretty sure that just
dd'ing a bootable CD won't properly recreate that part.
I think stuff like the ISO9660 TOC (table of contents)
might also require special handling.

If that readcd app handles all those issues you'll almost
certainly have better luck with that.  However, depending
on the layout of the data on the CD, a simple dd could
yield an image that's usable in all other respects as a
passive data disk.