1970年以来,用于信息存储的光盘技术与光盘系统一直都在进化,现在光存储已开始向大容量磁记录的统治地位挑战。在光记录系统中,录下一个比特所占的尺寸与所用的光波长大体相同,因此存储密度可较磁系统高10倍,寿命也较磁盘长10倍(后者每两年必须更新)。光盘介质有三种。一是只读介质,用于娱乐、软件和数据库分配;二是一次书写、多次阅读(WORM),供个人存档(或称随录随 Optical disc technology and optical disc systems for information storage have been evolving since 1970, and optical storage has now begun to challenge the dominance of high-capacity magnetic recording. In optical recording systems, the size of a bit recorded is about the same as the wavelength of light used, so the storage density can be 10 times higher than a magnetic system and 10 times longer than a magnetic disk (the latter must be updated every two years). There are three types of optical media. One is read-only media, used for entertainment, software and database allocation; the second is a written, multiple reading (WORM) for personal archiving (or as recorded