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  Wikipedia: Commodore 64

Wikipedia: Commodore 64
Commodore 64
From Wikipedia, the free encyclopedia.

The Commodore 64 (C64, CBM 64) was a popular home computer of the 1980s. Announced by Commodore Business Machines (founded and owned by Jack Tramiel) in January 1982 and released in September of that year at a price of US$595, it offered unprecedented value (sound and graphics performance) for the money. Its very aggressive pricing in comparison to competitors quickly started a price war. With estimated sales between 17 and 25 million units by the time it was discontinued in 1993, the C64 became and remains the best-selling computer model of all time.


The cost of building each C64 was estimated at US$135 due to Commodore's vertical integration (Commodore owned MOS Technologies, who made most of the chips), leaving a large margin to work with. Commodore marketed the machine aggressively, selling it in department stores, discount stores, and toy stores in addition to its network of authorized dealers. This allowed it, like its predecessor, the VIC-20, to compete against video game consoles. In 1983, Commodore offered a $100 rebate in the United States on the purchase of a C64 upon receipt of any video game console or computer.

The success of the VIC-20 and C64 contributed significantly to the departure of Texas Instruments from the home computer field (see TI-99/4A) and to the infamous video game crash of 1983.

Commodore attempted in 1984 to replace the C64 with the Commodore Plus/4, which offered a higher-color display, a better implementation of BASIC (V3.5), and built-in software. However, it lacked sprite capability and had poorer sound, and couldn't compete with the C64's software library. It flopped, while the C64 soldiered on. As more advanced computers came onto the market, including the C64's actual successor, the fully compatible C128 (late 1985), Commodore positioned the '64 as an entry-level computer, lowering the price as necessary.

In 1986, Commodore released the Commodore 64C computer, which was functionally identical to the original, but whose exterior design was remodelled in the spirit of the C128 to reflect "modernism". The C64C often came bundled with the third-party GEOS GUI-based operating system.

At the time of its introduction, the C64's graphics and sound capabilities were rivaled only by the Atari 8-bit family. Due to its advanced graphics and sound, the 64 is often credited with starting a computer subculture known as the Demo Scene. As of the turn of the millennium, it is still being actively used as a demo machine, especially for music (its sound chip even being used in special sound cards for PCs). For all others than special enthusiasts, however, the C64 lost its top position when the 16-bit Atari ST and Commodore Amiga were released in the mid-80s.


The C64 used an 8-bit 6510 microprocessor (a close derivative of the 6502 which had the ability to bank-switch the machine's ROM in and out of the processor's address space) and had 64 kilobytes of RAM, of which 38 KB were available to BASIC. In the UK, the C64 rivalled the British-built Sinclair ZX Spectrum in popularity, benefitting from a full-sized full-travel keyboard and more advanced graphics and sound chips.

The graphics chip, VIC-II, featured 16 colors, eight sprites, scrolling capabilities, and two bitmap graphics modes. The standard text mode featured 40 columns, like most Commodore PET models. Computer/video game and demo programmers quickly learned how to exploit quirks in the VIC-II to gain additional capabilities, like making more than 8 sprites appear, and move, simultaneously.

The sound chip, SID, had three channels 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 computer sound chips then available as "primitive, obviously (...) designed by people who knew nothing about music."

Unfortunately, the onboard BASIC programming language offered no easy way to tap the machine's advanced graphics and sound capabilities, so the user needed to either use PEEK and POKE commands to directly access the associated memory addresses to achieve the required results, or program in assembly language. Commodore had a better implementation of BASIC but reportedly chose to ship the C64 with the same BASIC 2.0 used in the VIC-20 for fear of the C64 eating into the sales of its PET/CBM line.

Peripherals and software

Although not commonly supplied with the machine, floppy disk drives of the 5.25 inch (Commodore 1541) and, later, 3.5 inch (1581) variety were available. Because the 1541 had a relatively poor reputation, a number of aftermarket drives also became available, offering better reliability, quieter operation, or simply a lower price, although often at the expense of compatibility. The C64 was often used with cassette tape drives (Datassettes) in Europe, although in the United States the C64 popularized the use of floppy drives, as it was the first computer that made them affordable.

Likewise, because Commodore offered a number of inexpensive modems for the C64, the machine also helped popularize the use of modems for telecommunications. In the United States, Quantum Computer Services (later America Online) offered an online service called Quantum Link for the C64 that featured chat, downloads, and online games. In the UK, Compunet was a very popular online service for C64 users (requiring special Compunet modems) from 1984 to the early 1990s.

The C64 amassed a large software library of nearly 10,000 titles, rivaled in its day only by the Apple II family. An Apple II+ emulator called the Spartan, manufactured by Mimic Systems Inc., was available for the C-64 but never gained much popularity. The C64's programs may still be run today even if one lacks the hardware, due to an abundance of software emulators for Amiga, Atari, MSDOS, Win32 and Linux systems. There are also special interface cables available, with software, to connect 1541 disk drives or C64s to PCs for emulation, archiving, and backup purposes.

Technical Information

  • CPU: MOS Technologies 6510
  • Clock speed: 0.985 MHz (PAL) / 1.023 MHz (NTSC)
  • Coprocessors: VIC-II (video), SID (sound)
  • RAM: 64 KB
  • ROM: 20 KB (8K BASIC 2.0, 8K KERNAL, 4K Character Generator)
  • Text modes: 40×25, 8×8 pixels monochrome; 40×25, 4×8 pixels (2 bits per pixel) multicolor
  • Graphics modes: 320×200 with 1 bit per pixel; 160×200 with 2 bits per pixel
  • Colours: 16
  • Sound: 3 voices / 6 octaves
  • I/O Ports:
    • Composite video (chroma/luma out and sound in/out)
    • TV RF output
    • 2 × joystick ports, Atari 2600 DB9 de facto standard
    • Cartridge/Expansion Slot
    • PET-type Datassette tape interface (300 baud)
    • User port with TTL-level RS-232 signals, for modems, etc; and byte-parallel signals
    • Serial bus (serial IEEE-488, DIN-type connector) for CBM printers and disk drives
  • Power Supply: 5V DC and 9V AC from external "power brick"


  • Commodore Business Machines, Inc., Computer Systems Division (1982). Commodore 64 Programmer's Reference Guide. Self-published by CBM. ISBN 0-672-22056-3.
  • Angerhausen, M.; Becker, Dr. A.; English, L.; Gerits, K. (1983, 84). The Anatomy of the Commodore 64. Abacus Software (US ed.) / First Publishing Ltd. (UK ed.). ISBN 0-948015-004 (UK ed.). German original edition published by Data Becker GmbH, Düsseldorf.

External links


From Wikipedia, the free encyclopedia. 
Modified by Geona