How Does that Work?
Welcome back to the newest installment of the "How It Works" series. Today we are going to talk about optical storage devices. In case you don't know, optical storage refers to any storage device that uses laser light technology to retrieve and store data. CD-ROM drives, CD players and DVD players are the most popular consumer electronics that fall under this category. By now, every household in America contains at least a CD player, and DVD is quickly gaining steam.
Today, just about every PC has a CD-ROM drive, and now we are going to find out exactly how it works. Unlike magnetic storage devices (hard drives, floppy disks, ZIP drives, etc) a majority of optical storage devices are "Read Only", meaning that they can be read from, but cannot be written to. Over the last few years, we have seen an insurgence in the market of "writable" and "re-writable" CD-ROM devices. These devices are capable of both writing to, and reading from optical disks. However, writing data with optical devices is time consuming, more technically challenging, and less reliable than recording with magnetic storage. Once the data is written, however, nothing short of physically damaging the disc will destroy the data.
Initially, the music and software industry was very opposed to the sale of Re-Writable CD-ROM drives, or "CD Burners" as they are commonly called. Concerns were raised about the usage of these devices for piracy. Nevertheless, the CD-R/W drive has become one of the most popular computer components sold and installed into consumer computer systems.
Humble beginnings in a big place
Sony and Philips joined forces in 1978 to cooperate on the development of current CD technology. Philips was already working on an optical storage medium, and Sony brought a ton of experience in digital recording. Initially the two companies were poised for a battle to create competing standards but they inked an agreement for a cooperative development project to create a single standard.
Sony originally wanted to use a 12 inch platter for the new optical disc (the same size as a standard vinyl LP), but Philips wanted to investigate smaller disc sizes, especially after they discovered that they could pack up to 12 hours of music onto a single 12 inch disk! Needless to say, this was overkill. The average music album is normally just over 1 hour long.
A 12 inch Laser Disc (LD) was also developed. The LD saw duty as a format for movie playback, and was used in Laser Disc based arcade games such as Dragon's Lair and Space Ace.
The LD failed to catch on as a mainstream replacement for the VHS video tape (this honor was reserved for DVD), but it did capture a niche market among audiophiles, who went to LD for its enhanced visual and sound quality. Movies are still being sold today in Laser Disc format, but are only produced in limited quantities.