Datapoint 2200

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Datapoint 2200 computer
Manufacturer Computer Terminal Corporation
Type Personal computer
Release date June 1970;48 years ago (1970-06)
Discontinued 1979;39 years ago (1979) [1]
Operating system Datapoint O/S
CPU 8-bit based, bit-serial, made from standard TTL components. The Intel 8008 was a nearly 100% compatible, but 8-bit parallel, 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 [2] and announced by CTC in June 1970 (with units shipping in 1971). It was 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. 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. [2] [3] Also significant is the fact that the terminal's multi-chip CPU (processor) became the basis of the x86 architecture used in the original IBM PC and its descendants.

Computer terminal computer input/output device; an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system

A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying or printing data from, a computer or a computing system. The teletype was an example of an early day hardcopy terminal, and predated the use of a computer screen by decades.


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.

Mainframe computer computers used primarily by corporate and governmental organizations

Mainframe computers or mainframes are computers used primarily by large organizations for critical applications; bulk data processing, such as census, industry and consumer statistics, enterprise resource planning; and transaction processing. They are larger and have more processing power than some other classes of computers: minicomputers, servers, workstations, and personal computers.


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. [4] 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 $30,000in 2017), and a full 16K Type 2 2200 had a list price of just over $14,000.

Computer keyboard device comprising an arrangement of buttons or keys used to input text in computers

In computing, a computer keyboard is a typewriter-style device which uses an arrangement of buttons or keys to act as mechanical levers or electronic switches. Following the decline of punch cards and paper tape, interaction via teleprinter-style keyboards became the main input method for computers.

The kilobyte is a multiple of the unit byte for digital information.

IBM Selectric typewriter

The IBM Selectric typewriter was a highly successful model line of electric typewriters introduced by IBM on 31 July 1961.

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

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]

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.

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), or at most a few integrated circuits. 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.

Central processing unit electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions

A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions. The computer industry has used the term "central processing unit" at least since the early 1960s. Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.

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. [5]

Transistor–transistor logic class of digital circuits built from bipolar junction transistors (BJTs) and resistors; transistors perform both the logic function (e.g., AND) and the amplifying function

Transistor–transistor logic (TTL) is a logic family built from bipolar junction transistors. Its name signifies that transistors perform both the logic function and the amplifying function ; it is the same naming convention used in resistor–transistor logic (RTL) and diode–transistor logic (DTL).

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.

Even though the Datapoint 2200 operated one bit at a time as a serial computer, the DataPoint 2200 performed faster than the 8008 chip. [6]

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.

Possibly because of their speed advantages compared to MOS circuits, Datapoint continued to build processors out of TTL chips until the early 1980s. [6]

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. [7] 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. [8]


Main unit


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

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  1. OLD-COMPUTERS.COM : The Museum
  2. 1 2 3 Lamont Wood, "Forgotten PC history: The true origins of the personal computer" Archived August 14, 2008, at the Wayback Machine ., Computerworld, August 8, 2008
  3. Allen Weinkrantz, "San Antonio Has Claim As The Birthplace of the Personal Computer. Read All About It.", June 2, 2009
  4. Datapoint 2200 Reference Manual Version I and Version II (PDF). Datapoint Corporation. 1972.
  5. Thompson Kaye, Glynnis (1984). A Revolution in Progress - A History to Date of Intel. Intel Corporation. p. 13. Order number:231295. "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."
  6. 1 2 Ken Shirrif. "The Texas Instruments TMX 1795: the first, forgotten microprocessor".
  7. Dalakov, Georgi (April 23, 2014). "History of Computers and Computing, Birth of the modern computer, Personal computer, Datapoint 2200".
  8. Wood, Lamont (August 8, 2008). "Forgotten PC history: The true origins of the personal computer; The PC's back story involves a little-known Texas connection". Computerworld, Inc.