30
Premmia PS Series
Using the Optical Drive{xe "Optical drive"}{xe "CD-
ROM drive"}{xe "DVD drive"}{xe "CDR-W drive"}{xe
"Music CDs"}{xe "MPEG-2"}
Your computer contains one of three optical drives:
•
a CD-ROM drive that you can use to access most compact disks
•
a DVD-ROM drive that you can use to access most compact disks and DVD disks
•
a CDR-W drive that you can use to access most kinds of compact disks, and record data
on special kinds of compact disks.
A CD-ROM (Compact Disk, Read Only Memory) disk can store up to 74 minutes of music
or 650MB of computer data and is read-only – you cannot change the data on the disk.
DVD-ROM disks can hold up to 18GB of data and are also read-only. Most DVD disks
contain movies or instructional videos; the video and audio data on DVD disks is
compressed using the MPEG-2 standard. In order to watch the movie, your computer needs
some way to decode the MPEG-2 data; the MPEG-2 decoder in your computer can be in
software (and use the processor to do all of the work) or in hardware (so the decoding is
shared between the processor and a specialized MPEG-2 decoder).
There are two standards for recording (writing) data to CDs: CD-R and CDR-W. CD-R is a
write-once technology – once the data is written to the disk, it cannot be changed or erased;
this makes CD-R an excellent choice for making permanent records of data. Data can be
written, erased and rewritten to CDR-W disks. The CDR-W drive in your computer
supports both CD-R and CDR-W technologies.
CDR-W cannot be read by all standard CD-ROM drives and CD players. The recording
material of a CDR-W disk isn't as reflective as a regular CD or a CD-R disk, so recorded
CDR-W disks are only readable in CD-ROM drives with CDR-W or multi-read
compatibility. While most new CD-ROM drives are compatible with CDR-W disks, many
existing drives cannot read CDR-W disks. So, if you are making an audio CD, you should
use CD-R disks that will play in your car or home stereo system, not CDR-W disks that
probably won’t. The CD-ROM, DVD-ROM and CDR-W drives available for your
computer can all read CDR-W disks.
There are two standards of writing to CD-R and CDR-W disks: pre-mastering and Drive
Letter Access (DLA). Pre-mastering software assembles all of the data, then writes all at one
time (or session) to the disk. A multi-session disk has several of these sessions recorded on
it.
