“The commodore 64 is, along with the Apple II and the Atari XL computers, the most famous home computer. According to the 2001 edition of Guinness book of records, the C64 was the most “prolific computing device ever manufactured”. During its production run from 1982 to 1993, about 30 million units were sold.
Superficially, the C64 closely resembled the VIC-20. It had the same casing, an identical keyboard configuration and virtually the same interfaces and sockets. But the apparent similarity belies some fundamental differences: a MOS 6510 processor and 64 KB of RAM which was quite unusually large at the time for a model of this price range.
Music synthesis was performed by a special sound interface chip. Sound envelope could be controlled on all three voices on a full nine octave of each. It was one of the first computers to offer both a high quality sound chip and graphic resolution with many colors and sprites.”
– Information received from Old-Computers.com