PC Repair and Maintenance: A Practical Guide (Charles River Media Networking/Security)

CD/DVD Drive Overview

Compact Disc (CD) and Digital Versatile Disc (DVD, formerly Digital Video Disc) drives are called optical drives because microscopic pits embedded into the discs are read by measuring reflected laser light. Read-Only Memory (CD-ROM) drives became popular around 1994 and represented a major improvement over floppies for program installation. They can also be used to read from CD data discs. Eventually came CD-R drives, which allowed discs to be burned (recorded) once only. There weren't too many of these made as they were quickly replaced by CD-RWs, which can be used with both single-use and rewritable discs. DVD-ROM drives were next. These are used to play DVD videos and read from data DVDs. More and more programs are becoming available on DVDs as well.

Unfortunately, there are several different incompatible types of DVD writable drives available, and the industry has not settled on a standard. The different types include the following:

DVD-R: Can write to a blank disc once. The discs are compatible with most recent DVD video players.

DVD-RW: Can be written and rewritten to. The discs are compatible with most recent DVD video players.

DVD+RW: Can be written and rewritten to. They can read and write to DVD-Rs. The discs are compatible with some DVD video players.

DVD-RAM: Can be written and rewritten to. The discs are not compatible with most DVD video players as of this writing.

Blu-ray Disc: A format not yet available as of this writing that allows for up to 27GB of data to be stored on a single DVD disc.

Some multi-standard drives are available. There are also discs with multiple layers and discs that can be flipped over to record on the other side, increasing the data capacity. Stay tuned; the industry will probably eventually come to an agreement on a single standard.