Datapoint 2200

Datapoint 2200 computer
Manufacturer	Computer Terminal Corporation
Type	Personal computer
Release date	June 1970 (1970-06)
Discontinued	1979 (1979)
Operating system	Datapoint O/S
CPU	8-bit, made from standard TTL components. The Intel 8008 was a nearly 100% compatible LSI implementation.
Memory	2 kB standard; expandable to 16 kB
Display	Text only, 80×12 characters

The Datapoint 2200 was a mass-produced programmable terminal, designed by Computer Terminal Corporation (CTC) founders Phil Ray and Gus Roche, and announced by CTC in June, 1970 (with units shipping in 1971). It was presented by CTC simply as a versatile, cost-efficient terminal for connecting to a wide variety of mainframes by loading various terminal emulations from tape rather than being hardwired as most terminals were. However, enterprising users in the business sector (including Pillsbury Foods) realized that this so-called "programmable terminal" was equipped to perform any task a simple computer could, and exploited this fact by using their 2200s as standalone computer systems. Its industrial designer John "Jack" Frassanito has later claimed that Ray and Roche always intended the Datapoint 2200 to be a full-blown personal computer, but that they chose to keep quiet about this so as not to concern investors and others. Also significant is the fact that the terminal's multi-chip CPU (processor) became the embryo of the x86 architecture upon which the original IBM PC and its descendants are based.

Technical description

The Datapoint 2200 had a built-in full-travel keyboard, a built-in 12-line, 80-column green screen monitor, and two cassette tape drives each with 130 kB capacity. Its size (approx. 2w×2d×1h ft) and shape (a box with protruding keyboard) approximated that of an IBM Selectric typewriter. Initially a Diablo 2.5 MB 2315-type removable cartridge hard disk drive was available, along with modems, several types of serial interface, parallel interface, printers and a punched card reader. Later, an 8-inch floppy disk drive was also made available, along with other, larger hard disk drives. An industry-compatible 7/9-track (user selectable) magnetic tape drive was available by 1975. In late 1977, Datapoint introduced ARCnet local area networking. The original Type 1 2200 shipped with 2 kilobytes of serial shift register main memory, expandable to 8K. The Type 2 2200 used denser 1 kbit RAM chips, giving it a default 4K of memory, expandable to 16K. Its starting price was around US$5,000, and a full 16K Type 2 2200 had a list price of just over $14,000. The 2200 models were succeeded by the 5500, 1100, 6600, 3800, 8800, etc.

The seed of the x86 architecture

Aside from being one of the first personal computers, the Datapoint 2200 has another connection to computer history. Its original design called for a single-chip 8-bit microprocessor for the CPU, rather than a conventional processor built from discrete TTL modules. In 1969, CTC contracted two companies, Intel and Texas Instruments, to make the chip. TI was unable to make a reliable part and dropped out. Intel was unable to make CTC's deadline. Intel and CTC renegotiated their contract, ending up with CTC keeping its money and Intel keeping the eventually completed processor.

CTC released the Datapoint 2200 using about 100 TTL components (SSI/MSI chips) instead of a microprocessor, while Intel's single-chip design, eventually designated the Intel 8008, was finally released in April 1972. Nonetheless the 8008 was to have a seminal importance. It was the father of Intel's line of 8-bit CPUs, which was followed by their assembly language compatible 16-bit CPU's—the first members of the x86-family, as the instruction set was later to be known. Already successful and widely-used, the x86 architecture's further rise after the success in 1981 of the original IBM Personal Computer with an Intel 8088 CPU means that most desktop, laptop and server computers in use today have a CPU instruction set directly based on the work of CTC's engineers. More immediately, the Intel 8008 was adopted by very early microcomputers including the SCELBI, MCM/70 and Micral N.

Credits

The original instruction set architecture was developed by Victor Poor and Harry Pyle. The TTL design they ended up using was made by Gary Asbell. Industrial design (how the box's exterior looked, including the company's logo) was done by Jack Frassanito.

Specifications

Main unit

• CPU: 8-bit, made from standard TTL components. The Intel 8008 was a nearly 100% compatible LSI implementation.
• RAM: 2K, expandable to 16K
• Display: Text only, 80×12 characters
• Storage: 2 tape drives, optional 8-inch Shugart floppy drive

Peripherals

Users of the 2200 and succeeding terminals eventually had several optional units to choose from. Among these were

• Modems
• Hard disks
• Printers
• ARCnet LAN

External links

• Information about the Datapoint 2200 at OLD-COMPUTERS.COM – Including a picture of the terminal
• Datapoint documentation on bitsavers.org
• Page with links to a doctoral thesis about early microprocessor history, with lots of details about Datapoint's role, and a copy of the Datapoint 2200 Programmer's Guide (both in PDF format) – both with a lot of historical detail.
• The man who invented the PC
• datapoint.org: Unofficial Datapoint Organization WEB site