翻译:Compact Disc-Read Only Memory (CD-ROM)
Optical discs for music are regarded as giving perfect playback,on matter how many times they are used (no hiss and creckles,as with a conventional vinyl record). As the disc is rigid and no parts touch the surface,track can be densely packed together.Optical disc have a 600 megabyte capacity and are well suited for computer applications needing vast storage.For example ,the whole of Europ's telephone directories could be stored on a couple of discs,and in fact the Post Office stores all britain's 24 million postal addreses on a 5-inch CD-ROM.The British library is developing a complete catalogue of it's books on a disc.
只读光盘存储器
一种直径约为5英寸的光盘，数据以一组坑的形式数字式地记录在盘的表面上。弱激光束扫过坑时从坑反射的失真就代表可用作“重放”的数据。CD-ROM广泛被用于音乐光盘唱机并且可以包含有程序检索和记忆功能。
音乐光盘不管使用多少次重放效果都相当好(没有像普通树脂唱片那样的嘶嘶声和噼啪声)。由于光盘是刚性的且无与表面接触的部件，所以可以把道微密地做在一起。光盘有600MB的容量，特别适于需要大存储量的计算机应用。例如，在两张光盘上可以存储全欧洲的电话簿，事实上英国邮局在一张5英寸CD-ROM上就存储了全英2400百万个邮政地址。英国图书馆正在研制把它收藏的书目全部装在一张光盘上。