Purple Book
Encyclopedia
Purple Book is the informal name for Sony
and Philips
' specification document for the double-density Compact Disc
(DDCD) format. The Purple Book format allows a CD to hold 1.3 Gigabyte
s by narrowing the track pitch from 1.6 to 1.1 micrometre
s, and shortening the minimum pit length from 0.833 to 0.623 micrometres.
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
and Philips
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....
' specification document for the double-density Compact Disc
Compact Disc
The Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...
(DDCD) format. The Purple Book format allows a CD to hold 1.3 Gigabyte
Gigabyte
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...
s by narrowing the track pitch from 1.6 to 1.1 micrometre
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
s, and shortening the minimum pit length from 0.833 to 0.623 micrometres.