still only one at a time, without requiring you to physically remove and replace the discs
in the drive. The discs that you use frequently can remain in the CD-ROM drive until they
are needed.
A single disc CD-ROM drive is mapped to the PC with a single drive letter, usually E:
or something close to that. However, a multidisc CD-ROM drive is mapped to the PC
with a drive letter for each disc it is capable of loading. Multiple disc drives also require
special software device drivers to give you access to each disc independently.Digital Versatile/Video Disc (DVD)
In attempts to develop a standard for a new high-density disc format, two formats were
proposed in the early 1990s: the Multimedia CD (MMCD), proposed by Philips and Sony,
andtheSuperDensityDisc(SDD),proposedbyaconsortiumofToshiba,Matsushita,and
Time-Warner. In 1995, a high-density format was accepted, largely based on the SDD
format—theDigital Versatile Disc (DVD), also called theDigital Video Disc. Figure 10-11
shows a DVD and drive in a PC.
The reasons you would want to install a DVD drive in your PC are still a little vague
beyond your desire to sit at your PC and watch movies. However, because a DVD drive
also reads CDs, it may be a good hedge against future technologies should more DVD
software or media become available. Many experts are saying that the DVD-RAM will be
the CD-R of the future, but this is still open to debate and remains to be seen.DVD Technology
A DVD can store the equivalent of 17 gigabytes (GB) or about 25 times more than a
CD-ROM. Through the use of MPEG (Motion Pictures Experts Group) and Dolby com-
pression technologies, a DVD can also store hours of high-quality audio-visual content,Chapter 10: CD-ROMs and DVDs^215
Figure 10-10. A multidisc CD-ROM drive