The Commodore 64 is an 8-bit home computer released by Commodore International in August, 1982, at a price of US$595. Preceded by the Commodore VIC-20 and Commodore MAX Machine, the C64 features 64 kilobytes (64×210 bytes) of RAM with sound and graphics performance that were superior to IBM-compatible computers of that time.[citation needed]

The Commodore 64 is commonly referred to as the C64 (sometimes written C= 64 to mimic the Commodore company logo) and occasionally known as CBM 64 (Commodore Business Machines Model number 64), or VIC-64. It has also been affectionately nicknamed the "breadbox" and "bullnose" due to its shape.

During the Commodore 64's lifetime (between 1982 and 1994), sales totaled around 30 million units, making it the best-selling single personal computer model of all time. At one point (1983/84/85), the Commodore 64 dominated the market with approximately 40% share, even outselling IBM PCs and Apple computers. Part of its success was due to the fact that it was sold in retail stores instead of electronics stores, and that Commodore produced many of its parts in-house to control supplies and cost.

Approximately 10,000 commercial software titles were made for the Commodore 64[citation needed] including development tools, office applications, and games. The machine is also credited with popularizing the computer demo scene. The Commodore 64 is still used today by some computer hobbyists, and various C64 emulators allow anyone with a modern computer to run these programs on their desktop.

The C64 used an 8-bit MOS Technology 6510 microprocessor. This was a close derivative of the 6502, with an added 6-bit internal I/O port that in the C64 is used for two purposes: to bank-switch the machine's ROM in and out of the processor's address space, and to operate the datasette tape recorder.

The C64 had 64 kilobytes of RAM, of which 38 KB were available to built-in Commodore BASIC 2.0.

The graphics chip, VIC-II, featured 16 colors, eight hardware sprites (more are possible via software multiplexing), scrolling capabilities, and two bitmap graphics modes. The standard text mode featured 40 columns, like most Commodore PET models; the built in font was not standard ASCII but PETSCII, an extended form of ASCII-1963.

The sound chip, SID, had three channels, each with its own ADSR envelope generator, and with several different waveforms, ring modulation and filter capabilities. It too, was very advanced for its time. It was designed by Bob Yannes, who would later co-found synthesizer company Ensoniq. Yannes criticized other contemporary computer sound chips as "primitive, obviously . . . designed by people who knew nothing about music." Often the game music became a hit of its own among C64 users. Well-known composers and programmers of game music on the C64 were Rob Hubbard, David Whittaker, Chris Hülsbeck, Ben Daglish, Martin Galway and David Dunn among many others. Due to the chip's limitation to three channels, chords were played as arpeggios typically, coining the C64's characteristic lively sound.

There are two versions of the SID chip. The first version was the MOS Technology 6581, which is to be found in all of the original "breadbox" C64s, and early versions of the C64C and the Commodore 128. It was later replaced with the MOS Technology 8580 in 1987. The sound quality was a little more crisp on the 6581 and many Commodore 64 fans still prefer its sound. The main difference between the 6581 and the 8580 was the voltage supply: the 6581 uses a 12 volt supply, while the 8580 required only 9 volts. A voltage modification can be made to use a 6581 in a C64C board (which uses 9V).

The SID chip has a distinctive sound which retained a following of devotees. In 1999, Swedish company Elektron produced a SidStation synth module, built around the 6581 model SID chip (as opposed the superior 8580), using remaining stocks of the chip. Several bands use these devices in their music.

(stolen from http://en.wikipedia.org/w iki/Commodore_64)