Just as audio compact disks have banished vinyl phonograph albums to the nostalgia bins, compact disks for computers may soon reduce the role of the familiar floppy disk.
After several years of slow growth, the use of compact-disk drives in personal computers is beginning to accelerate.
Computer market researchers say there are about 2.5 million CD-ROM drives in use. More than 750,000 drives have been sold in the last six months, and the researchers say there may be 8 million to 10 million CD-ROM drives in use by 1995.
Why the sudden surge in interest? Several factors appear to be at work, and are cause for giving serious consideration to CD-ROM (which stands for Compact Disk-Read Only Memory).
First, prices of CD-ROM drives, as well as of the powerful personal computers needed to run them efficiently, have fallen. Dell Computer Corp., for example, has introduced two multimedia PCs equipped with CD-ROM drives and the ability to produce color graphics and stereo sound, for as little as $2,000. Similar systems cost twice that much just a year ago. Apple Computer Inc. included a CD-ROM drive in its Macintosh IIvx computer last fall and is reportedly planning to add CD-ROM drives to other models in the near future.
External CD-ROM drives are now widely available for less than $500, although some of the more advanced models still cost $1,000 or more. Many drives come with an assortment of software. Creative Labs Inc. has a Sound Blaster Multimedia upgrade kit for $799, which includes a sound board and a good selection of software.
Software is getting much better. Compton's New Media Inc. introduced an "interactive encyclopedia" for computers using the Microsoft Windows operating environment. This is the first encyclopedia with obvious advantages over the printed book. Also, several computer game companies have harnessed the powers of CD-ROM to add movie clips, stereo sound and better graphics to their programs. A roundup of some of the best CD-ROM titles will be included in a future column.
Compton's has also announced that it has signed deals to provide CD-ROM software to national video rental and music store chains, book stores and other nontraditional software outlets. The possibility of renting a program for a few dollars, and even a CD-ROM drive for a few dollars more, will certainly fuel the interest in the technology.
For another thing, the drives are getting easier to use. Early CD-ROM drives were often a challenge to navigate, but the rising popularity of Microsoft Windows has created a de facto standard for controlling a CD-ROM drive on an IBM-style PC, although the software needed to get the computer to talk to the CD-ROM drive (and vice versa) is still vexing. The Apple Macintosh is still the easiest system for attaching and using a CD-ROM drive.
Basic standards for CD-ROM hardware and software are starting to emerge. More than a dozen computer makers have endorsed a standard called MPC, which is supposed to assure the user that any computer marked MPC will be able to play any software marked MPC. Compton's may have gone even further, asserting that it has developed a technology that will allow one of its CD-ROM titles to play on virtually any computer, whether Macintosh, Windows or one of the half-dozen other competing formats.
The MPC standard itself is rather mundane, however. When you shop for a drive, it makes sense to spend a little more for advanced technology that will last a few years. The buzzwords are average access time (how quickly the drive can fetch some information once you hit the key) and data transfer rate (the faster the rate, the smoother the audio and video signals).
Access time should not be any higher than 380 milliseconds; under 300 milliseconds is better. By contrast, a regular hard disk drive may have an access time of less than 20 milliseconds.
A data transfer rate of 150 kilobits per second (150 kbps) is common; 300 kbps is the best. A drive designated CD-ROM/XA is the latest thing. If the idea of storing your family photo album on a PC is appealing, make sure the drive is compatible with Kodak PhotoCD.
Furthermore, software companies are looking to CD-ROM as a way to reduce the stacks of floppy disks and reams of documentation that constitute the newer software operating systems such as IBM's OS/2, as well as some of the more powerful business applications.
A single CD-ROM disk can hold more than 500 megabytes of information, the equivalent of hundreds of today's high-density diskettes. Not even Windows NT, the next generation of Windows, expected later this year, can fill that much space, at least not yet.
(Peter Lewis works out of the New York Times' Austin, Texas, bureau:  328-8258.)