CD-ROM is an acronym for Compact Disc-Read Only Memory and is a type of compact disc that has read-only data, meaning that once data has been recorded onto the disc, it can only be read or played and cannot be altered or erased. A CD-ROM is a type of optical disc and can be read by a computer with an optical drive, or CD-ROM drive, and a DVD/Blu Ray Drive. It’s used to store programs and files that require large amounts of data storage. A CD-ROM holds between 650-700 megabytes (MB) of data, meaning it has enough memory to store approximately 300,000 pages of text.
History of CD-ROM
The compact disc was introduced in 1982 for digital audio reproduction. But because a compact disc can hold any type of digital information, the disc was adapted by the computer industry in the mid-1980s for a low-cost storage solution for large computer programs, graphics, and databases. Because the storage capacity was considered large, it quickly replaced the floppy disk, which has a maximum capacity of 1.4 MB.
CD-ROMs became popular for distributing software and data for computers and video game consoles after Microsoft launched the first CD-ROM software in 1987 called Microsoft Bookshelf. By 1992, Macintosh by Apple released the Macintosh IIvx computer with a CD-ROM drive included. Video game manufacturers then began using the technology to get their products to market.
Compared to a laptop, CD-ROMs take up a lot of space, meaning the drive that reads them also takes up too much space, particularly in a laptop. Modern computers no longer feature the CD-ROM drive and instead use the space for extended battery life, improved performance, and enhanced graphics.
CD-ROMs are now rarely used because of their comparatively low storage capacity compared to solutions such as DVDs, hard drives, and solid state drives. In addition, software is now mainly digitally distributed, making the CD-ROM’s purpose obsolete.
How CD-ROMs work
A CD-ROM drive operates by using a laser to reflect light off the bottom of the CD-ROM. The reflected light pulses are then read by a photo detector. The incoming pulses are decoded by the microprocessor and are sent to the computer to be processed. The disc itself is reflective and is composed of 1.2mm of polycarbonate plastic. A CD-ROM looks very similar to an audio CD (CD-DA) and stores and receives data in a similar way.