A Compact Disc (CD) is an optical storage device capable of holding up to 650 MB of digital data. It uses a 4.75-inch reflective disk, and utilizes laser technology for data reading. CDs come in various forms such as CD-ROM, CD-R, and CD-RW.
A computer memory device consisting of a platter with a magnetically encoded surface that retrieves data by being spun past read heads. Disks can be internal (hard disks) or removable. A common example is the Compact Disc (CD).
