资料来源 : Free On-Line Dictionary of Computing

Compact Disc Read-Only Memory
     
         (CD-ROM) A {non-volatile} optical data storage
        medium using the same physical format as audio {compact
        discs}, readable by a computer with a CD-ROM drive.
     
        CD-ROM is popular for distribution of large databases,
        software and especially {multimedia} {applications}.  The
        maximum capacity is about 600 megabytes.  A CD can store
        around 640 {megabytes} of data - about 12 billion bytes per
        pound weight.
     
        CD-ROM drives are rated with a speed factor relative to music
        CDs (1x or 1-speed which gives a data transfer rate of 150
        {kilobytes} per second).  12x drives were common in April
        1997.  Above 12x speed, there are problems with vibration and
        heat.  {Constant angular velocity} (CAV) drives give speeds up
        to 20x but due to the nature of CAV the actual throughput
        increase over 12x is less than 20/12.
     
        20x was thought to be the maximum speed due to mechanical
        constraints but on 1998-02-24, {Samsung Electronics}
        introduced the SCR-3230, a 32x CD-ROM drive which uses a ball
        bearing system to balance the spinning CD-ROM in the drive to
        reduce noise.
     
        CD-ROM drives may connect to an {IDE} interface, a {SCSI}
        interface or a propritary interface, of which there are three
        - Sony, Panasonic, and Mitsumi.  Most CD-ROM drives can also
        play audio CDs.
     
        There are several formats used for CD-ROM data, including
        {Green Book CD-ROM}, {White Book CD-ROM} and {Yellow Book
        CD-ROM}.  {ISO 9660} defines a standard file system.
     
        See also {Compact Disc Recordable}, {Digital Versatile Disc}.
     
        {Byte, February 1997
        (http://www.byte.com/art/9702/sec17/art5.htm)}.
     
        (1998-03-16)