Question

What is the advantage of having smaller regions for data encryption on a CD or DVD?

Answer 1

The first disc that could be written and read by optical means (using light as a medium) was developed by James T. Russell. In the late 1960s, Russell created a system that recorded, stored, and played audio/video data using light rather than the traditional contact methods, which could easily damage the disks during playback. Russell developed a photosensitive disc that stored data as 1 micron-wide dots of light and dark. The dots were read by a laser, converted to an electrical signal, and then to audio or visual display for playback.

Russell's own company manufactured the first disc player in 1980, although the technology never reached the marketplace until Philips and Sony developed the technology. In late 1982, Philips and Sony released the first of the compact disc (CD) formats, which they then called CD-DA (digital audio). In the years since, format has followed format as the original companies and other industry members developed more adaptations of the original specifications.

Digital Versatile disc (DVD) had its beginning in 1994, when two formats, Super disc (SD) and Multimedia CD (MMCD) were introduced. Promoters of the competing technologies failed to reach an agreement on a single standard until 1996, when DVD was selected as a convergence format. DVD has, in the few years since, grown to include variations that do anything that CD does, and more efficiently. Standardization and compatibility issues aside, DVD is well-placed to supplant CD.