CDROM or Compact Disc Read Only Memory is a type of media that is
used to store data. The device that reads this media is a CDROM drive.
The CDROM drive is fairly simple in the way it operates. The CDROM drive
reads the CDROM by spinning the media around at high speeds, while a laser
reflects itself off of the surface of the CDROM. The surface is "notched"
in patterns to form representative data.
There are various speeds at which a CDROM drive can run. Most new CDROMs
run at speeds over 24x. The speed is measured in the number of times faster
the drive reads compared to a single speed drive. When evaluating the quality
of a CDROM drive, it is common to look at the access time and the data
transfer rate. The access time is a measurement of the time required to
locate a particular data source on the media. The data transfer rate refers
to the speed at which the information can be transferred to the main memory.
CDROM devices are usually connected to the motherboard via a SCSI or
IDE connection. Due to cost and need, most computers generally use an IDE
connection. The IDE connection is referred to as Secondary IDE, and the
CDROM drive is typically set to master on the secondary IDE port.
CDROMs were standardized by the International Standards Organization
(ISO) to encourage universal compatibility between CDROM drives.