Unlike
floppy discs and
hard drives,
CD-ROMs are not made up of many
concentric tracks --
CDs are essentially one long string of
data in a
spiral*. From the
CD-R FAQ:
[Discs are composed of] multiple sessions composed of multiple tracks composed of sectors, and the data in the sectors is interleaved and spread over a large area.
There's more to a
CD than this. The lead-in
data (at the beginning of the
spiral) and
subcode data (pretty much stored
beneath the
spiral) can be difficult to
read and harder to
write. Again from the
CD-R FAQ:
Making a "bit-for-bit" copy of a disc would require reading the data at the lowest possible level, something that no production CD-ROM drive is capable of doing. Even if it were possible, there aren't any CD recorders that can write that sort of data.
With all that said, a
German company named Elaborate
Bytes has produced a
software package named
CloneCD which seems to be able to
duplicate just about any
CD:
http://www.elby.de/english/corp/index.htm
CloneCD, being able to create near 1:1 copies of copy-protected CDs, has earned a place in the hearts of pirates everywhere -- see Usenet newsgroup alt.binaries.cd.image.clonecd for details.
* According to Andy Poggio's excellent (if dated)
CD-ROM Technical Summary -- From Plastic Pits to "Fantasia", the single
spiral track on a
CD is around 3
miles long (just under 5
kilometers).