VHS stands for "Video Home System" and refers to the name given to the standard 1/2" tape format used in Video Cassette Recorders (VCR's). Introduced in 1977, the VHS recorder proved to be much more popular than the Sony "Betamax" format. By 1988, the "Beta" systems had all but disappeared.
DVD's ("Digital Versatile Discs" or also "Digital Video Discs") were first introduced in 1996. By 1999 they had become the standard format used by major motion picture studios. Home DVD players and recorders are expected to replace the VHS recorders by the year 2007.