T
heCD-ROM (Compact Disc-Read Only Memory)wasn’t developed specifically for the
PC. It was designed initially for use as an audio storage device to replace the cassette
tape. It hasn’t been totally successful in that mission—cassettes are still around—but
it has gained acceptance and proven to be very popular. However, the CD-ROM did
discover a ready and willing market of personal computer users. The CD-ROM and its
comparatively huge storage capacity (over floppy disks) was very attractive to software
and multimedia producers and soon virtually all software, including databases, books,
encyclopedias, and other materials not available to the PC in the past suddenly became
very available and accessible for the PC.
Because the majority of software titles are available only on CD-ROM, today’s PCs
have a CD-ROM drive. A CD-ROM drive is as common on PCs today as floppy drives
were only a few years ago. In fact, some manufacturers now replace the floppy disk drive
with a single CD-ROM on their latest PC models. The CD-ROM is by far the most common
method of software distribution and data storage due to their combination of high capacity
and easy, inexpensive manufacturing.
When CD-ROMs were first introduced to the market, most software distributors
included floppy disks along with the CD-ROM version of the program or provided a cou-
pon that could be mailed in for a CD-ROM version of the software. In the past few years,
this was reversed, and the coupon became the means of getting a diskette version of a
software package. Today, the coupon has disappeared altogether and the CD-ROM is
now the only option available. A PC without a CD-ROM drive simply is not able to install
the vast majority of PC software available on the market today. Some CD-ROM software
even requires that your PC’s drive meet a specific minimum requirement. For example, if
you have an older CD-ROM drive, such as a 4X, in your system, it may need to be replaced
before it can run some newer CD-ROM titles that require at least a 12X drive.The Technology of the CD and CD-ROM
The CD-ROM uses compact disc (CD) technology, the same technology used to record
the music on your favorite audio CDs. The physical media used for recording data,
programs,music,andmultimediaonaCD-ROMisthesameasthatusedtorecordmusic.
In fact, the physical disc (see Figure 10-1) is the same for both.CD-ROM Formats
There are a number of different formats and applications of the CD technology, not all of
which are for the computer. The two that most people are familiar with are the formats used
for music CDs and data CD-ROMs, but there are a few others. Theformatof the CD is the pat-
ternandmethodusedtorecorditscontents.TheCDisoftencomparedtotheoldvinylrecord
because they are produced in a similar fashion and their contents is recorded in a spiraling
pattern, as opposed to data arranged in tracks, as on a music cassette or a disk drive.(^202) PC Hardware: A Beginner’s Guide