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[the following article is from the August 1985 issue of COMPUTE! Magazine]
 
Monster Memory
 

The CD-ROM, an acronym for Compact Disc-Read Only Memory, is a compact disc audio player which has been slightly modified for general purpose data storage and interfaced to a computer. At CES, Atari demonstrated a sample disc that contained a 23-volume, nine-million-word encyclopedia.       Compact disc players are the latest rage among audiophiles. Up to 75 minutes of digitally encoded music can be stored in the form of microscopic pits on a 4.7-inch rigid plastic disc. Inserted in a special player, the disc spins at 300 r.p.m. while a miniature laser reads the pits. The data is decoded by a microprocessor, then converted into standard audio signals which are fed into the auxiliary input or tape monitor jacks on a stereo receiver. The result is exceptionally pure music of unprecedented dynamic range and frequency response, free of surface noise and tape hiss. Furthermore, since the disc is read by a laser, not a diamond stylus, compact discs last virtually forever with no deterioration. They can also tolerate rougher handling than ordinary records and tapes.       But music isn't the only thing a compact disc can store. Any type of information can be digitized and recorded on a disc. That includes text, graphics, and computer programs. And the capacity is enormous: A single compact disc stores about 550 megabytes. A megabyte equals 1,024K, so that's roughly equivalent to 1,564 floppy disks on an IBM PC, 3,520 disks on a Commodore 1541 drive, 4,022 disks on an Apple II, 4,469 enhanced-density 1 disks on an Atari [8-bit], or 6,400 single-density Atari disks. They're cheap, too: compact discs can be mass-produced at a manufacturing cost of a few dollars each (audio discs currently retail for about $15). Because audio CDs and CD players are already in mass production, CD-ROMs can debut at affordable prices.       A compact disc is a read-only storage medium, so you can't record data on it yourself. But CDs are ideal for storing large databases that don't have to be updated often. At CES, Atari demonstrated a sample disc that contained a 23-volume, nine-million-word encyclopedia. The encyclopedia was transferred to the CD from magnetic tape, where it was stored in punchcard format-the equivalent of 976,000 punchcards. Yet, it fits on one quarter of the space of a single CD.       To think of a CD simply as an efficient way to store mass amounts of information is to miss the point, however. Like a floppy disk drive, a CD player is a random-access device; it can seek and retrieve any piece of data on the disc in a few seconds without hunting through the information sequentially. Therefore, a CD-ROM can find the slightest, most obscure fact in a massive database in less time than it takes you to pull a book off a shelf and flip it open to the index.

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see also: Report From The Summer Consumer Electronics Show
 
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