Datapoint 2200

Last updated

Datapoint 2200 computer
Manufacturer Computer Terminal Corporation
Type Personal computer
Release dateJune 1970;49 years ago (1970-06)
Discontinued1979;41 years ago (1979) [1]
Operating system Datapoint O/S
CPU discrete logic implementation of the Intel 8008 instruction set
Memory2 KB standard; expandable to 16 KB
DisplayText only, 80×12 characters

The Datapoint 2200 was a mass-produced desktop personal computer, designed by Computer Terminal Corporation (CTC) founders Phil Ray and Gus Roche [2] and announced by CTC in June 1970 (with units shipping in 1971). It was initially presented by CTC simply as a versatile and cost-efficient terminal for connecting to a wide variety of mainframes by loading various terminal emulations from tape rather than being hardwired as most contemporary terminals, including their earlier Datapoint 3300. [3] However, Dave Gust, a CTC salesman, realized that the 2200 could meet Pillsbury Foods's need for a small computer in the field, after which the 2200 was marketed as a stand-alone computer. [3] 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. [2] [4] Also significant is the fact that the terminal's multi-chip CPU (processor)'s instruction set became the basis of the Intel 8008 instruction set, which inspired the Intel 8080 instruction set and the x86 instruction set used in the processors for the original IBM PC and its descendants.


Technical description

The Datapoint 2200 had a built-in full-travel keyboard, a built-in 12-line, 80-column green screen monitor, and two 47 character-per-inch cassette tape drives each with 130  KB capacity. Its size, 9 58 in × 18 12 in × 19 58 in (24 cm × 47 cm × 50 cm), and shapea box with protruding keyboardapproximated that of an IBM Selectric typewriter. [5] 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 (equivalent to $32,000in 2019), and a full 16K Type 2 2200 had a list price of just over $14,000.

The 8-bit processor architecture that CTC designed for the Datapoint 2200 was implemented in four distinct ways, all with nearly identical instruction sets, but very different internal microarchitectures: CTC's original design that communicated data serially, CTC's parallel design, the Texas Instruments TMC 1795, and the Intel 8008. [6]

Datapoint 2200 Version II (CTC's parallel design) was much faster than the TMC 1795, which was slightly faster than the original serial design of the Datapoint 2200, which in turn was considerably faster than the 8008. [7]

The 2200 models were succeeded by the 5500, 1100, 6600, 3800/1800, 8800, etc.

The fact that most laptops and cloud computers today store numbers in little-endian format is carried forward from the original Datapoint 2200. Because the original Datapoint 2200 had a serial processor, it needed to start with the lowest bit of the lowest byte in order to handle carries. The big-endian format is used by older processor families (the 6800, 8051, etc., and their descendants). Microprocessors descended from the Datapoint 2200 (the 8008, Z80, and the x86 chips used in most laptops and cloud computers today) kept the little-endian format used by that original Datapoint 2200. [7] [8]

The seed of the x86 architecture

The original design called for a single-chip 8-bit microprocessor for the CPU, rather than a processor built from discrete TTL modules as was conventional at the time. 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. [2]

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. [9]

Even though the Datapoint 2200 processor design employed a 1-bit microarchitecture, operating serially one bit at a time, it performed faster than the Intel 8008 microprocessor which employed an 8-bit microarchitecture. [7]

Possibly because of their speed advantages compared to MOS circuits, Datapoint continued to build processors out of TTL chips until the early 1980s. [7]

Nonetheless the 8008 was to have a seminal importance. It was the basis of Intel's line of 8-bit CPUs, which was followed by their assembly language compatible 16-bit CPUs — 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. The instruction set of the highly successful Zilog Z80 microprocessor can also be traced back to the Datapoint 2200 as the Z80 was backwards-compatible with the Intel 8080. More immediately, the Intel 8008 was adopted by very early microcomputers including the SCELBI, MCM/70 and Micral N.


The original instruction set architecture was developed by Victor Poor and Harry Pyle. [10] 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. [2]


Main unit


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

Related Research Articles

Intel 8080 8-bit microprocessor

The Intel 8080 ("eighty-eighty") is the second 8-bit microprocessor designed and manufactured by Intel. It first appeared in April 1974 and is an extended and enhanced variant of the earlier 8008 design, although without binary compatibility. The initial specified clock rate or frequency limit was 2 MHz, and with common instructions using 4, 5, 7, 10, or 11 cycles this meant that it operated at a typical speed of a few hundred thousand instructions per second. A faster variant 8080A-1 became available later with clock frequency limit up to 3.125 MHz.

Intel 8086 16 bit microprocessor

The 8086 is a 16-bit microprocessor chip designed by Intel between early 1976 and June 8, 1978, when it was released. The Intel 8088, released July 1, 1979, is a slightly modified chip with an external 8-bit data bus, and is notable as the processor used in the original IBM PC design.

Intel 80386 family of 32-bit microprocessors introduced in 1985, including DX, SX and SL models

The Intel 80386, also known as i386 or just 386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistors and were the CPU of many workstations and high-end personal computers of the time. As the original implementation of the 32-bit extension of the 80286 architecture, the 80386 instruction set, programming model, and binary encodings are still the common denominator for all 32-bit x86 processors, which is termed the i386-architecture, x86, or IA-32, depending on context.

Microprocessor Computer processor contained on an integrated-circuit chip

A microprocessor is a computer processor that incorporates the functions of a central processing unit on a single integrated circuit (IC) of MOSFET construction. The microprocessor is a multipurpose, clock driven, register based, digital integrated circuit that accepts binary data as input, processes it according to instructions stored in its memory and provides results as output. Microprocessors contain both combinational logic and sequential digital logic. Microprocessors operate on numbers and symbols represented in the binary number system.

Motorola 6800 8-bit microprocessor

The 6800 is an 8-bit microprocessor designed and first manufactured by Motorola in 1974. The MC6800 microprocessor was part of the M6800 Microcomputer System that also included serial and parallel interface ICs, RAM, ROM and other support chips. A significant design feature was that the M6800 family of ICs required only a single five-volt power supply at a time when most other microprocessors required three voltages. The M6800 Microcomputer System was announced in March 1974 and was in full production by the end of that year.

P5 (microarchitecture) Intel microporocessor

The first Pentium microprocessor was introduced by Intel on March 22, 1993. Its P5 microarchitecture, also sometimes referred to as i586, was the fifth generation for Intel, and the first superscalar IA-32 microarchitecture. As a direct extension of the 80486 architecture, it included dual integer pipelines, a faster floating-point unit, wider data bus, separate code and data caches and features for further reduced address calculation latency. In October 1996, the Pentium with MMX Technology was introduced, complementing the same basic microarchitecture with the MMX instruction set, larger caches, and some other enhancements.

Zilog Z80 8-bit microprocessor

The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were delivered in March 1976, and it was officially introduced on the market in July 1976. With the revenue from the Z80, the company built its own chip factories and grew to over a thousand employees over the following two years.

In computing, endianness is the ordering or sequencing of bytes of a word of digital data in computer memory storage or during transmission. Endianness is primarily expressed as big-endian or little-endian.

In computer architecture, 8-bit integers, memory addresses, or other data units are those that are 8 bits wide. Also, 8-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size. '8-bit' is also a generation of microcomputers in which 8-bit microprocessors were the norm.

Microcomputer A small computer, with a processor made of one or a few integrated circuits

A microcomputer is a small, relatively inexpensive computer with a microprocessor as its central processing unit (CPU). It includes a microprocessor, memory and minimal input/output (I/O) circuitry mounted on a single printed circuit board (PCB). Microcomputers became popular in the 1970s and 1980s with the advent of increasingly powerful microprocessors. The predecessors to these computers, mainframes and minicomputers, were comparatively much larger and more expensive. Many microcomputers are also personal computers.

Intel 8008 byte-oriented microprocessor

The Intel 8008 is an early byte-oriented microprocessor designed and manufactured by Intel and introduced in April 1972. It is an 8-bit CPU with an external 14-bit address bus that could address 16 KB of memory. Originally known as the 1201, the chip was commissioned by Computer Terminal Corporation (CTC) to implement an instruction set of their design for their Datapoint 2200 programmable terminal. As the chip was delayed and did not meet CTC's performance goals, the 2200 ended up using CTC's own TTL-based CPU instead. An agreement permitted Intel to market the chip to other customers after Seiko expressed an interest in using it for a calculator.

Intel 8085 8-bit microprocessor invented in 1976

The Intel 8085 ("eighty-eighty-five") is an 8-bit microprocessor produced by Intel and introduced in March 1976. It is a software-binary compatible with the more-famous Intel 8080 with only two minor instructions added to support its added interrupt and serial input/output features. However, it requires less support circuitry, allowing simpler and less expensive microcomputer systems to be built.

Datapoint computer company

Datapoint Corporation, originally known as Computer Terminal Corporation (CTC), was a computer company based in San Antonio, Texas, United States. Founded in July 1968 by Phil Ray and Gus Roche, its first products were, as the company's initial name suggests, computer terminals intended to replace Teletype machines connected to time sharing systems.

Federico Faggin Italian physicist and electrical engineer

Federico Faggin is an Italian-American physicist, engineer, inventor and entrepreneur. He is best known for designing the first commercial microprocessor, the Intel 4004. He led the 4004 (MCS-4) project and the design group during the first five years of Intel's microprocessor effort. Faggin also created, while working at Fairchild Semiconductor in 1968, the self-aligned MOS (metal–oxide–semiconductor) silicon-gate technology (SGT), which made possible MOS semiconductor memory chips, CCD image sensors, and the microprocessor. After the 4004, he led development of the Intel 8008 and 8080, using his SGT methodology for random logic chip design, which was essential to the creation of early Intel microprocessors. He was co-founder and CEO of Zilog, the first company solely dedicated to microprocessors, and led the development of the Zilog Z80 and Z8 processors. He was later the co-founder and CEO of Cygnet Technologies, and then Synaptics.

Masatoshi Shima Japanese computer pioneer

Masatoshi Shima is a Japanese electronics engineer. He was one of the architects of the world's first microprocessor, the Intel 4004. Working for Busicom in Japan, in 1968 he did the logic design for a specialized CPU to be translated into three-chip custom chips. In 1969, he worked with Intel's Ted Hoff and Stanley Mazor to reduce the three-chip Busicom proposal into a one-chip architecture. In 1970, that architecture was transformed into a silicon chip, the Intel 4004, by Federico Faggin, with Shima's assistance in logic design.

The history of general-purpose CPUs is a continuation of the earlier history of computing hardware.

A serial computer is a computer typified by bit-serial architecture – i.e., internally operating on one bit or digit for each clock cycle. Machines with serial main storage devices such as acoustic or magnetostrictive delay lines and rotating magnetic devices were usually serial computers.

74181 7400 Series TTL Arithmetic Logic Unit IC

The 74181 is a 4-bit slice arithmetic logic unit (ALU), implemented as a 7400 series TTL integrated circuit. The first complete ALU on a single chip, it was used as the arithmetic/logic core in the CPUs of many historically significant minicomputers and other devices.

The history of the personal computer as a mass-market consumer electronic device began with the microcomputer revolution of the 1970s. A personal computer is one intended for interactive individual use, as opposed to a mainframe computer where the end user's requests are filtered through operating staff, or a time-sharing system in which one large processor is shared by many individuals. After the development of the microprocessor, individual personal computers were low enough in cost that they eventually became affordable consumer goods. Early personal computers – generally called microcomputers – were sold often in electronic kit form and in limited numbers, and were of interest mostly to hobbyists and technicians.

Victor "Vic" Poor was an American engineer and computer pioneer. At Computer Terminal Corporation, he co-created the architecture that was ultimately implemented in the first successful computer microprocessor, the Intel 8008. Subsequently, Computer Terminal Corporation created the first personal computer, the Datapoint 2200 programmable terminal.


  1. "Datapoint Corporation Datapoint 2200". OLD-COMPUTERS.COM : The Museum.
  2. 1 2 3 4 Wood, Lamont (August 8, 2008). "Forgotten PC history: The true origins of the personal computer". Computerworld.
  3. 1 2 Wood, Lamont (2013). Datapoint: The Lost Story of the Texans Who Invented the Personal Computer. Hugo House Publishers, Ltd. pp. 102–103. ISBN   9781936449361.
  4. Weinkrantz, Allen (June 2, 2009). "San Antonio Has Claim As The Birthplace of the Personal Computer. Read All About It". Archived from the original on March 4, 2016.
  5. Datapoint 2200 Reference Manual Version I and Version II (PDF). Datapoint Corporation. 1972.
  6. Shirriff, Ken (August 30, 2016). "The Surprising Story of the First Microprocessors". IEEE Spectrum .
  7. 1 2 3 4 Shirriff, Ken. "The Texas Instruments TMX 1795: the first, forgotten microprocessor".
  8. "Oral History Panel on the Development and Promotion of the Intel 8008 Microprocessor" (PDF). September 21, 2006. p. 5.
  9. Thompson Kaye, Glynnis (1984). A Revolution in Progress - A History to Date of Intel (PDF). Intel Corporation. p. 13. "The 8-bit 8008 microprocessor had been developed in tandem with the 4004 and was introduced in April 1972. It was originally intended to be a custom chip for Computer Terminals Corp. of Texas, later to be known as Datapoint." "As it developed, CTC rejected the 8008 because it was too slow for the company's purpose and required too many supporting chips."
  10. Dalakov, Georgi (April 23, 2014). "History of Computers and Computing, Birth of the modern computer, Personal computer, Datapoint 2200".