A History of Commodore’s 8-bit Computers

Best known for the Commodore 64, the best selling model in the history of computing, Commodore International was one of the first companies to enter the personal computing market. That first model was the Commodore PET.

Before the PET

Commodore got it start long before personal computers arrived. It was founded in Toronto, Ontario, Canada in 1954 as the Commodore Portable Typewriter Company by Polish immigrant Jack Tramiel. The company incorporated as Commodore Business Machines in 1955. In 1962, it was listed on the New York Stock Exchange as Commodore International.

When Japanese imports forced most North American typewriter manufacturers out of business in the late 1950s, Tramiel moved to adding machines. Then in the late 1960s, Japanese adding machines hit the North American market, once again threatening Commodore’s existence.

Tramiel went to Japan to figure out how to compete and came back with the idea of producing electronic calculators instead of mechanical adding machines. Once again, Commodore had a successful product on its hands – until in 1975 Texas Instruments (TI) entered the market with calculators that cost less than Commodore was paying for parts (and TI was one of Commodore’s important suppliers).

Tramiel decided to head in another direction, took out a $3 million loan, and acquired chip manufacturer MOS Technology, Inc. to assure a steady supply of chips for his gear. Part of the agreement was that Chuck Peddle, MOS Tech’s chip designer, would join Commodore.

KIM-1 single-board computer

Commodore’s First Computer

Before home computers, there were hobbyist computers. The KIM-1 was one of the first, developed as a way for MOS Technology to demonstrate its 6502 CPU. The KIM-1 was the world’s first single-board computer when it was released in 1976. It had 1 KB of memory, an LCD display, a cassette interface, and 15 input/output ports. It sold for $245 and only required a power supply and some sort of enclosure for the 9″ x 10″ board.

This became the basis for many different projects and laid the foundation for Commodore’s first personal computer, released in 1977.

The Commodore PET

Commodore PET 2001Peddle convinced Tramiel that calculators were a dead end, so they should turn their attention to the fledgling personal computer market (often called home computers back then). Peddle designed a machine with a metal case, a keyboard, a monitor, and a built-in cassette tape drive for loading and saving software and files. This was the Commodore PET 2001, which came to market in October 1977.

The PET was named in part for the pet rock fad, which had lasted about six months during 1975. Silly as it sounds, 1.5 million pet rocks were sold during that period for $4.00 each, making their creator a millionaire. Officially, P.E.T. stood for Personal Electronic Transactor.

Apple II with 9-inch composite monitor and two floppy drivesThere were only two other home computers at that time: The Apple II, also built around the MOS 6502 CPU, had arrived in June 1977, replacing the Apple 1, which had been more of a do-it-yourself project. The Apple II sold for $1,298 with 4 KB of memory and could be used with a composite monitor or TV (with an RF modulator) and cassette tape recorder, which many home already had.

Radio Shack TRS-80 Model IThe other was the TRS-80 Model I, on sale at Radio Shack stores across the US since August 1977. It was based on the Zilog Z-80 CPU, and the 4 KB version retailed at $599 with a screen and tape recorder.

The PET sold for $495 with the same 4 KB as its competitors. Commodore could only produce 30 units per day, and orders came in so quickly that Tramiel decided to raise the price to $595. Next Commodore started pushing the 8 KB version at $795, since the 4 KB model left only 3 KB available for the user. In all, Commodore sold 500 PETs in 1977.

Commodore acquired a license for BASIC from Microsoft allowing it to install Commodore BASIC on as many machines as it could produce for a single, one-time fee. Over the years, it was installed on tens of millions of Commodore computers.

Commodore PET 2001 keyboard

One clever feature of the PET and later Commodore computers was the PETSCII character set, also known as CBM ASCII. In addition to the standard characters found on a keyboard, Commodore computers had a whole range of graphical symbols that could be accessed from the keyboard – and these characters were even printed on the key caps for easy access.

Commodore PET 2001-N with a real keyboardThe biggest complain about the original PET was its keyboard, which was laid out in a grid (see above keyboard layout) and not like a typewriter keyboard. Within a year Commodore introduced the PET 2001-N, which removed the tape drive and added a real keyboard with a numeric keypad.

In 1978, Commodore also expanded to Europe, where it sold its computers for twice as much as in the States – and it found ready buyers. European models were called CBM models, since Philips had a trademark on the PET name. The first models were the CBM 3008 (8 KB), 3016 (16 KB), and 3032 (32 KB).

In 1979, Commodore introduced its first floppy drive, the CBM 2040 dual drive with DOS 1.0 built into it. Like later Commodore floppy drives, it is an intelligent device with its own CPUs (two of them) and RAM that connected to the PET’s IEEE-422 parallel port. Each disk could hold 170 KB of data. Single drive mechanisms came later.

Because Commodore DOS was built into the floppy drive, you had to get a new drive to get the latest version of DOS. The 2040 had DOS 1.0, the 4040 used 2.0 and later 2.1, the 8050 included DOS 2.5 and support for 500 KB high-density disks, and the 8250 had DOS 2.7 and could store 1 MB on a double-sided 5.25″ high-density floppy.

By 1980, the PET had moved from its original 9″ display to a 12″ screen, and the metal case had been replaced by a plastic one. The European versions were the called the CBM 4016 and 4032.

Commodore also introduced the 8000 series, which featured 80 characters per row instead of 40 and was geared more toward business use.

VIC-20: The Wonder Computer for the 1980s

Commodore VIC-20PETs were monochrome computers, but Apple had been selling color computers since 1976. Commodore jumped on the color bandwagon with a new model designed for the home market and intended to be hooked up to your TV or a color monitor. The Commodore VIC-20 was a price breakthrough at US$299.99 when it was released in 1980.

It was first introduced in Japan, where it was called the VIC-1001. It proved such a hit that some Japanese companies cancelled their plans for lower-cost computers.

VIC stands for Video Interface Chip, the component that lets the VIC-20 display color. As for the 20, nobody knows for sure. The VIC-20 displays 22 characters of text per line and 23 lines of text, and with a 16 KB memory cartridge it has 21 KB of RAM, but Michael Tomczyk, Commodore’s VIC Czar, says the number just sounded friendly.

The VIC-20 used the same 1 MHz 6502 CPU found in the PET and Apple II, but it was equipped with far less memory than other 1980 machines – just 5 KB, of which 3.5 KB was available for programs. It used the PETSCII character set, had 4 function keys on the right, worked with an Atari joystick, and had a cartridge slot for games, programs, and memory expansion to a maximum of 40 KB.

VIC-20 ad with William Shatner

Commodore pushed VIC-20 to the masses, including an ad campaign featuring William Shatner, Captain Kirk from Star Trek. And where PETs were sold exclusively by computer dealers, VICs were sold in stores such as K-mart.

Perhaps the most popular accessory was the Commodore 1530 C2N-B Datasette, which was much less expensive than a floppy drive, besides which the 1540 floppy drive wasn’t available until 1982.

Text adventures from Adventure International were put on cartridge and generated over $1.5 million in sales for Commodore.

Commodore developed the first modem to retail for under US$100 for the VIC-20, and the VICModem became the first modem to sell 1 million units.

Commodore sold over 1 million units, and in 1982 it was the best selling computer on the market. But it was about to be eclipsed by a more expensive upstart, and Commodore ended up dropping its price below $100 in April 1983. Commodore production of the VIC-20 ended in 1984.

Commodore 64: The Upstart

Rather than wait for the VIC-20 to peak before introducing its successor, Commodore chose to strike while the iron was hot and get the Commodore 64 to market as quickly as it could at the price point it wanted to reach. 64 KB of RAM cost over $100 in 1981, yet Commodore aimed at a US$595 retail price. Because Commodore owned MOS Technology and made most of its own chips, and because memory prices kept falling, it knew $595 was an attainable target.

Commodore 64

In January 1982, the very year that the VIC-20 was the best selling personal computer, Commodore previewed the Commodore 64 (C-64) at the Consumer Electronics Show. It would go on to become the best selling single computer model of all time, as attested by Guinness World Records, although the exact number sold is unknown (at least 10 million and possibly as many as 17 million).

Where the VIC-20 had 5 KB of RAM, the C-64 had 64 KB. Where the VIC-20 had 23 lines of 22 characters, the C-64 had 24 lines of 40 characters. Commodore had a new version of the VIC chip, a new sound chip, and an enhanced version of the 6502 CPU known as the 6510 that let the computer access a full 64 KB of memory alongside 20 KB of ROM.

The VIC-1540 floppy drive was introduced for the VIC-20 in 1982. It includes DOS 2.6 and connects to the VIC-20 via a serial port. (Previous Commodore drives used the parallel port found in PETs and CBM models. The VIC-20 and its descendants do not have parallel ports.) Its 170 KB disk format is “mostly compatible” with earlier PET/CBM floppy drives.

The VIC-20 was the first personal computer to sell for under US$1,000 with a floppy drive.

The Commodore 64 was officially introduced in August 1982. Despite serious competition at home from Atari’s 8-bit computers and the Apple IIe, the $595 C-64 was the value champion at half the price of the Apple IIe with no need to add cards for floppy drives, printers, modems, and so on. (In the UK, the competition came from the BBC Micro and Sinclair ZX Spectrum.)

For VIC-20 owners, it was easy to move the Datasette and a printer to the C-64. The VIC-1540 floppy drive was not compatible with the C-64, so Commodore released the 1541 floppy drive for the C-64, which originally retailed at US$399.95. The 1541 also uses DOS 2.6.

The success of the VIC-20 and C-64 helped drive the Timex Sinclair 1000 and Texas Instruments 99/4A out of the market during the 1983 home computer price war. Commodore dropped the C-64 to $300 in June 1983, which TI countered by selling for TI 99/4A for $99 – and losing money on every sale.

The Commodore 64 remained on the market until 1994, 12 years after its introduction. Commodore had hoped to keep the C-64 going for another year but ended up filing for bankruptcy in April 1994.

Commodore Bombs

Despite the success of the VIC-20 and C-64, Commodore made some poor moves while trying to grow its market.

Max – or Not

Commodore MAX MachineCommodore tried to sell a game console in 1982. It was called Max Machine in Japan, Ultimax in the US, and VC-10 in Germany. With just 2 KB of RAM, the same 6510 CPU as the C-64, and a target price of US$200, it couldn’t compete with the VIC-20 for value. It was discontinued within a few months due to dismal sales in Japan.

A C-64 to Go

Zenith Z-160 portableIn 1983, Commodore introduced the SX-64 executive computer, a portable C-64 along the lines of Osborne, Kaypro, Compaq, Zenith (left, and a machine that I used for a brief time while working for a Heath/Zenith store way back in the late 1980s), and other luggable CRT-based portables larger than a big briefcase. The SX-64 has a built-in 1541 floppy drive (with storage space above the drive for a stack of floppies) and a 5″ CRT display. It sold for US$995 and was the first of these portables to include a color display.

Commodore SX-64 executive computerThe SX-64 was a thing of beauty, as you can see by enlarging its image on the CBM Museum website (in German). We’ve reduced it significantly for use here. The attention to detail tells you Commodore really did intend the SX-64 as an executive machine.

The SX-64 did not sell well, even as Commodore discounted its retail price to move inventory.

Commodore 16

Commodore 16Trying to replace the VIC-20, Commodore introduced the Commodore 16 in 1984. It has just 16 KB of memory, used a 7501 or 8501 CPU, and was intended to compete with sub-$100 computers. By the time the C-16 shipped, Timex Sinclair, Mattel, and Texas Instruments had left the home computer market.

Visually, it was quite attractive with its dark grey case and VIC-20/C-64 styling.

But the C-16 had an inferior graphics chip vs. the C-64, had no modem port, could not connect to the existing Datasette, and had no game port, making it in many ways inferior to the VIC-20. Commodore did produce a C-16 compatible Datasette and joysticks for the C-16, but this model never caught on in the US market.

An even cheaper machine, the Commodore 116, was sold in Europe. Although functionally identical to the C-16, it had a smaller case and a rubber chiclet keyboard.

Commodore Plus/4

Commodore Plus/4Released in June 1984, the Plus/4 was similar to the C-64 and also had four built-in applications, an office suite with a word processor, database, spreadsheet, and graphics program. It is more compatible with the C-16 than with the C-64 – however, that wasn’t a good thing. The C-64 was selling for US$199 when the Plus/4 came to market at US$299.

Although Commodore considered the Plus/4 its flagship model, it never sold well and was finally phased out in 1988.

Finally, Something Better

Commodore 128

The Commodore 64 would not die. Newer models were doing nothing to cut into its maker. The C-64 was joined by the Commodore 128 in January 1985. The new model has two 64 KB banks of memory, supports 80-column text, includes an extended keyboard with a numeric keypad, and contains a Zilog Z-80 CPU, enabling it to run CP/M software from the business world – although but processors cannot run at the same time.

The C-128’s primary CPU is an 8502 running at 2 MHz, twice the speed of the VIC-20 and C-64. The C-128 has three operating modes: native C-128 mode, CP/M mode, and C-64 mode that is nearly 100% compatible with the older machine’s software.

Commodore sold 4 million C-128s before it was discontinued in 1989. The C-64 remained on the market until 1994.

Commodore 1571 double-sided disk driveCommodore introduced two new floppy drives for the C-128, both running CBM DOS 3.0. The single-sided 1570 floppy drive uses the same 170 KB format as previous Commodore computers – and it can also read CP/M formatted floppies – and MS-DOS disks with additional software. The 1571 is a double-sided floppy drive with double the storage. Commodore was unable to keep up with demand for the US$300 double-sided 1571.

Commodore 128DCommodore 128D

Later in 1985, Commodore released the Commodore 128D, which follows the styling of the Amiga 1000 and DOS PCs with a separate keyboard. The 128D was the first 8-bit Commodore with a built-in floppy drive – the 1571 mentioned above. It even had a handle on the left side to facilitate transporting the computer.

In late 1986, Commodore introduced a “cost reduced” version of the 128D in North America and parts of Europe. The 128DCR had a metal chassis in place of the plastic one in the original and eliminated the carrying handle.

C-64, the Next Generation

Commodore 64CIn 1986, Commodore introduced a refreshed version of the C-64 called the Commodore 64C. It is functionally identical to the earlier model but takes its styling cues from the Commodore 128.

Another Bomb

In 1990, Commodore repackaged the C-64 as a gaming console to compete with the Nintendo Entertainment Systems (NES) and the SegaMaster System. Commodore went after the US market but never got any traction. The C64GS was another commercial failure for Commodore.

The Big Step Forward: Amiga

The future of 8-bit home computers was drawing to a close by the mid 1980s. The IBM PC had established the Intel 8088, a 16-bit CPU with an 8-bit data bus, as the business standard, and Apple introduced its Lisa business computer in 1983, followed by the first Macintosh in 1984. These were the first commercial computers with a graphical user interface and a mouse, something Microsoft quickly copied in developing Windows for the IBM PC and compatible clones.

Lisa and Macintosh used the Motorola 68000 CPU, a 32-bit chip with 24-bit addressing on a 16-bit data bus. Commodore chose the same CPU for its next computer family, the Amiga, which we cover in another article.

Further Reading

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