This article is from the RCA SelectaVision VideoDisc FAQ, by email@example.com (Tom Howe) with numerous contributions by others.
The MCA DiscoVision system was first offered for sale on December 15,
1978 when a small quantity of discs and players were made available (and
sold out) in Atlanta, Georgia. So the public availability of DiscoVision
predates CED by over two years. Many people have the perception that CED
is older because of field testing RCA began in 1975, and extensive press
coverage in 1976 and 1977 that suggested the CED system was nearly ready
for market introduction. And LaserDisc did not achieve a nationwide
market until about the same time CED was introduced.