[4] It has been listed in the Guinness World Records as the highest-selling single computer model of all time,[5] with independent estimates placing the number sold between 12.5 and 17 million units.

[8] For a substantial period (1983–1986), the C64 had between 30% and 40% share of the US market and two million units sold per year,[9] outselling IBM PC compatibles, the Apple II, and Atari 8-bit computers.

In the United States, it has been compared to the Ford Model T automobile for its role in bringing a new technology to middle-class households via creative and affordable mass-production.

[15] Approximately 10,000 commercial software titles have been made for the Commodore 64, including development tools, office productivity applications, and video games.

With the support of Al Charpentier (engineer of the VIC-II) and Charles Winterble (manager of MOS Technology), they proposed to Commodore CEO Jack Tramiel a low-cost sequel to the VIC-20.

The chips were complete by November, by which time Charpentier, Winterble, and Tramiel had decided to proceed with the new computer; the latter set a final deadline for the first weekend of January, to coincide with the 1982 Consumer Electronics Show (CES).

The design, prototypes, and some sample software were finished in time for the show, after the team had worked tirelessly over both Thanksgiving and Christmas weekends.

The C64 made an impressive debut at the January 1982 Consumer Electronics Show, as recalled by Production Engineer David A. Ziembicki: "All we saw at our booth were Atari people with their mouths dropping open, saying, 'How can you do that for $595?

'"[6][21] The answer was vertical integration; due to Commodore's ownership of MOS Technology's semiconductor fabrication facilities, each C64 had an estimated production cost of US$135 (equivalent to $350 in 2022).

This deal meant that the consumer could send the TS1000 to Commodore, collect the rebate, and pocket the difference; Timex Corporation departed the computer market within a year.

One key to the C64's success was Commodore's aggressive marketing tactics, and they were quick to exploit the relative price/performance divisions between its competitors with a series of television commercials after the C64's launch in late 1982.

[34] Although many early C64 games were inferior Atari 8-bit ports, by late 1983, the growing installed base caused developers to create new software with better graphics and sound.

That gave us a lot of color capability that had not been exploited.With sales booming and the early reliability issues with the hardware addressed, software for the C64 began to grow in size and ambition during 1984.

Adjusted to the population size, the popularity of Commodore 64 was the highest in Finland at roughly 3 units per 100 inhabitants,[46] where it was subsequently marketed as "the Computer of the Republic".

In the European market, disk software was rarer and cassettes were the most common distribution method; this led to a higher prevalence of arcade titles and smaller, lower-budget games that could fit entirely in the computer's memory without requiring multiloads.

[66] Schools did not prefer the Educator 64 to the wide range of software and hardware options the Apple IIe was able to offer, and it was produced in limited quantities.

[68] While earlier computers using this form factor only incorporate monochrome ("green screen") displays, the base SX-64 unit features a 5 in (130 mm) color cathode-ray tube (CRT) and one integrated 1541 floppy disk drive.

[70][71] The successors had many improvements such as a BASIC with graphics and sound commands (like almost all home computers not made by Commodore[72][73][74]), 80-column display ability, and full CP/M compatibility.

The decision to make the Commodore 128 plug compatible with the C64 was made quietly by Bowen and Herd, software and hardware designers respectively, without the knowledge or approval by the management in the post Jack Tramiel era.

The designers were careful not to reveal their decision until the project was too far along to be challenged or changed and still make the impending Consumer Electronics Show (CES) in Las Vegas.

[75] In the United States, the 64C was often bundled with the third-party GEOS graphical user interface (GUI)-based operating system, as well as the software needed to access Quantum Link.

Q-Link was a modified version of the PlayNET system, which Control Video Corporation (CVC, later renamed Quantum Computer Services) licensed.

These are used for two purposes in the C64: to bank-switch the machine's read-only memory (ROM) in and out of the processor's address space, and to operate the datasette tape recorder.

This feature is often used by tape and disk fast loaders and the KERNAL cassette routine to keep a standard CPU cycle timing not modified by the VIC-II's sharing of the bus.

By utilizing interrupts to reset hardware registers with precise timing, it was possible to place graphics within the borders and use the full screen.

Much of the cost was initially eliminated by reducing the number of discrete components, such as diodes and resistors, which enabled a smaller printed circuit board.

At such high clock rates the chip generated considerable heat, forcing MOS Technology to use a ceramic dual in-line package known as a CERDIP.

After a redesign in 1983, the VIC-II was encased in a plastic dual in-line package; this reduced costs substantially, but did not eliminate the heat problem.

The effectiveness of the cardboard was questionable; it acted instead as an insulator, blocking airflow and trapping heat generated by the SID, VIC, and PLA chips.

It has several innovations, including selection (via the restore key) of KERNAL and character ROMs, built-in reset toggle on the power switch, and an S-Video socket to replace the original TV modulator.