When doing the duplication of a CD, there are
two major phases; first setting up the data, or
information, to go onto the CD and then writing
that details to the CD.
Throughout the first phase, the information is
placed into what is identified as an 'optical disc
image, i.e. setting up an image that keeps the
information that will then be transmitted onto
To set-up this image, all the data that is to go
into the disc is organized into a one file and
arranged to suit what will be reading the CD.
This not only allows the audience to recognize
the information included on the disc, but also
where the details are included on the disc so it
can go directly to different parts of the
information, like a particular music track.
As soon as the information is gathered and all
set for the CD duplication to take place, it is then
arranged on the disc with a lead in, or start
point, to tell the CD reader where the details
starts with the disc, a table of contents to
explain where and what the data is, and a lead
out point to indicate where the information has
This standard was designed so that CDs will
work in all compact disc players and readers. In
this file program are different modes, with
Mode 1 CD-ROM used for CD-ROMs and Form 2
CD-ROM Mode 2 used for audio and video data.
Nowadays lasers are used in most cases to write
the information to the optical disc during CD
Duplication. These types of lasers need to be
adjusted to the right power, and this will rely on
the kind of disc being used, what is going onto
the disc and how.
Read only cds use a natural dye on the area for
the reflection variants, while re-write discs have
a metallic alloy that is dissolved to produce
reflection versions. Even so, a different laser
calibration is expected to both write and read
each kind of disc, as the comparison in
reflectivity is different.
Read only discs have a greater reflective
variation, and therefore generally better quality,
while re-write CDs have a lower reflective
variation that has lower quality but the greater
versatility of use of the disc due to its rewritable
Even though both kinds of duplication are
included into most recorders these days, they do
however call for the right connectivity. Again,
this is generally consistent, with interior
recorder drives using the ATA parallel
connections and external drives using the PATA
Laser technology is clearly a key element of disc
duplication technology and lasers are always
being created further.
Because more and more details has been
needed to fit onto a single disc, the wavelength
of the lasers used has had to reduce in order to
pack it in, with the corresponding laser used at
the readers also needed to be this smaller
Normally, the lasers used to duplicate a disc are
significantly more effective than those used to
read it, as the writing laser needs to modify the
surface attributes of the disc while the reader
laser needs to keep the surface unaltered.
Laser recorders are officially called Laser Beam
Recorders (LBRs) wherein most of the issues can
now be different to generate the different
wavelengths needed for different kinds of discs.