medium using the same physical format as audio
compactdiscs, readable by a computer with a CD-ROM drive.
CD-ROM is popular for distribution of large databases,
maximum capacity is about 600 megabytes. A CD can store
around 640
megabytes of data - about 12 billion bytes per
pound weight.
CD-ROM drives are rated with a speed factor relative to music
CDs (1x or 1-speed which gives a data transfer rate of 150
kilobytes per second). 12x drives were common in April
1997. Above 12x speed, there are problems with vibration and
to 20x but due to the nature of CAV the actual throughput
increase over 12x is less than 20/12.
20x was thought to be the maximum speed due to mechanical
introduced the SCR-3230, a 32x CD-ROM drive which uses a ball
bearing system to balance the spinning CD-ROM in the drive to
reduce noise.
CD-ROM drives may connect to an
IDE interface, a
SCSIinterface or a propritary interface, of which there are three
- Sony, Panasonic, and Mitsumi. Most CD-ROM drives can also
play audio CDs.
There are several formats used for CD-ROM data, including
(1998-03-16)