The CD-ROM and DVD-ROM drive are
devices that read data, music and video off of a CD (compact
disc) or DVD (Digital Versatile or Video Disc). The ROM part
stands for "Read Only Memory", which means the disc
can only be read from, but not written to. More commonly today,
CDs and DVDs can be both read and written to. Drives are
typically labeled DVD-RW, indicating the drive is capable of
reading (R) and writing (W).
The CD replaced the floppy disk
as the medium of choice for storage of tranportable data. When
you purchase software today, it is stored on CDs. The DVD
has even greater capacity and is supplanting the CD. Breakthroughs
with high defintion technology is increasing the capacity of
DVDs even further.
A CD or DVD is spun at high speed
inside the drive while a laser is directed at the surface to
read or write data. The drive speed is referenced
as 12X or 12 speed (or any other number). This simply means
that it spins the CD that many times faster than the original
industry specification. So, a 48X CD-ROM spins the CD up to
48 times faster than the original specification. Faster is
better. The speeds of a read-write drive are expressed
like this, 4X 4X 32X. This means it can write to the disc up
to 4 times the spec speed, rewrite the disc up to 4 times spec
speed and read the disc up to 32 times the spec speed.
