List of early microcomputers

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This is a list of early microcomputers sold to hobbyists and developers. These microcomputers were often sold as "DIY" kits or pre-built machines in relatively small numbers in the mid-1970s. These systems were primarily used for teaching the use of microprocessors and supporting peripheral devices, and unlike home computers were rarely used with pre-written application software. Most early micros came without alphanumeric keyboards or displays, which had to be provided by the user. RAM was quite small in the unexpanded systems (a few hundred bytes to a few kilobytes). By 1976 the number of pre-assembled machines was growing, and the 1977 introduction of the "Trinity" of Commodore PET, TRS-80 and Apple II generally marks the end of the "early" microcomputer era, and the advent of the consumer home computer era that followed.

Contents

Discrete logic

Before the advent of microprocessors, it was possible to build small computers using small-scale integrated circuits (ICs), where each IC contained only a few logic gates or flip-flops.

Test, single-board and development machines

As microprocessors were developed, companies often released simple development systems to bootstrap the use of the processor. These systems were often converted by hobbyists into complete computer systems.

Intel's Intellec computers were a series of early microcomputers Intel produced starting in the 1970s as a development platform for their processors.

This is a sortable list; click on the icon at the top of each column to sort by the contents of that column.
ModelProcessorYearFormatRemarksRef
Intel SIM8-01 Intel 8008 early 1972bare boardIntel's developer kit for the 8008
MOS Technology KIM-1 MOS Technology 6502 1975complete boardMOS's developer kit for the 6502, widely used in a number of projects
Motorola MEK6800D2 Motorola 6800 1976complete board
MPT8080 MicrotutorIntel 80801977complete boardA trainer type single-board-computer. As recently as 2008, it remained in academic use. [2] As of 2011, the MPT8080 was still available for sale.
Rockwell AIM-65 65021978complete board
Synertek SYM-1 65021978complete board
Intel SDK-85 Intel 8085 1978
Tesla PMI-80 Intel 8080 clone1982complete boardA czechoslovakian d single-board microcomputer.

Kits

Many early microcomputers were available in Electronic kit form. Machines were sold in small numbers, with final assembly by the user. Kits took advantage of this by offering the system at a low price point. Kits were popular, beginning in 1975, with the introduction of the famous Altair 8800, but as sales volumes increased, kits became less common. The introduction of useful fully assembled machines in 1977 led to the rapid disappearance of kit systems for most users. The ZX81 was one of the last systems commonly available in both kit and assembled form.

Some magazines published plans and printed circuit board layouts from which a reader could in principle duplicate the project, although usually commercially made boards could be ordered to expedite assembly. Other kits varied from etched, drilled, printed circuit boards and a parts list to packages containing cases, power supplies, and all interconnections. All kits required significant assembly by the user.

This is a sortable list; click on the icon at the top of each column to sort by the contents of that column.
ModelProcessorYearFormatRemarksRef
SCELBI Intel 8008 1974Was the earliest commercial kit computer based on the Intel 8008 microprocessor. Sold for embedded control applications. [3]
Mark-8 Intel 80081974Plans published; an etched board was available but constructors had to source all parts [4]
MITS Altair 8800 Intel 8080 1975Etched boards and partsIntroduced S-100 bus
IMSAI 8080 Intel 8080 1975
Comp-Sultants Micro 440 Intel 4040 1975First 4040-based micro
SWTPC 6800 Motorola 6800 1975Introduced SS-50 bus
COSMAC ELF RCA 1802 1976
Apple I MOS Technology 6502 1976Assembled PCB; buyer supplied rest of components
Nascom, Nascom 1 Zilog Z80 1977
Nascom 2Z801979
Telmac 1800 RCA 18021977
Newbear 77-68 Motorola 6800 1977
Heathkit H8 Intel 80801977All parts, case and power supply, detailed instructions Heathkit was a notable manufacturer of electronics kits
Heathkit H11 LSI-11 1977All parts, case and power supply, detailed instructionsA 16-bit microcomputer compatible with a PDP-11
Electronics Australia 77up2 aka "Baby 2650" Signetics 2650 1977
Netronics ELF II RCA 18021977
Quest SuperELFRCA 18021974
Elektor TV Games Computer Signetics 26501979
System 68Motorola 68001977 Electronics Today International magazine project
PSI comp 80 Z801979By Powertran from a design in the magazine Wireless World
Science of Cambridge MK14 National Semiconductor SC/MP 1978Low-cost kit expandable to video output [5]
Acorn System 1 65021979
Tangerine Microtan 65 65021979Rack-based extendible system
Compukit UK101 65021979 Practical Electronics magazine project (clone of Ohio Scientific Superboard II)BASIC in ROM
Sinclair ZX80 Z801980Among the last popular kit systems
Sinclair ZX81 Z801981Among the last popular kit systems
MicroBee Zilog Z801982The computer was conceived as a kit, with assembly instructions included in Your Computer magazine, in February 1982. [6]
The Digital Group Zilog Z80 1975Kits or assembled PCBs. Including cases from 1978The first company to produce mostly complete systems built around the Zilog Z80 processor. Their products also included options for MOS 6502 and Motorola 6800 processors.

Complete microcomputers

A number of complete microcomputers were offered even before kits became popular, dating to as far back as 1973. For some time there was a major market for assembled versions of the Altair 8800, a market that grew significantly through the late 1970s and into the early 1980s. The introduction of three computers aimed at personal users in 1977, the Radio Shack TRS-80, Apple II, and Commodore PET, significantly changed the American microcomputer market and led to the home computer revolution.

This is a sortable list; click on the icon at the top of each column to sort by the contents of that column.
ModelProcessorYearRemarksRef
Q1 Corporation, Q1 Intel 8008 1972The first general purpose microcomputer to ship with a built in alphanumeric user interface. First sold in December 72. [7]
MicroSystems International CPS-1MIL MF71141972Using a locally produced microprocessor based on the design of the Intel 4004. First built in 1972, a small number shipped in early 1973. [8] [9]
Micral N 1973Awarded the title of "the first personal computer using a microprocessor" by a panel at the Computer History Museum in 1986. [10]
Sord Computer Corporation SMP80/08 Intel 8008 1974Was announced in early 1973, but never commercially released. It was followed by the SMP80/x, which debuted in May 1974 and used the Intel 8080. [11]
MCM/70 Intel 8008 1974Primarily designed to run APL. According to the IEEE Annals of Computer History, the MCM/70 is the earliest commercial, non-kit personal computer. [12]
IBM 5100 1975An early portable computer with integrated monitor; the 5100 was possibly one of the first portable microcomputers using a CRT display.
Sphere 1 1975A personal computer that was among the earliest complete all-in-one microcomputers that could be plugged in, turned on, and be fully functional.
Processor Technology Sol-20 1976Offered both as kit and assembled, but the vast majority were sold assembled.
Tandberg Radiofrabrikk/Tandberg Data TDV-2114 Intel 8080 1976One of the first all-in-one microcomputers developed in Europe. It was sold as a complete package, with CPU-module, Memory-modules and a 8" floppy-disk drive w/module all built into a case with a TDV-2115 dumb-terminal. It was initially marketed towards businesses as an "intelligent terminal" and workstation, running Tandberg-OS (having the look and feel of Intel ISIS-II). After the separation of Tandberg Data, this machine would also be available in OEM form as the Siemens System 6.610. [13] [14] [15]
Radio Shack TRS-80 Zilog Z80 1977Mainly targeting North America, it was very popular as a home computer.
Apple II 6502 1977Quickly became the leading business desktop workstation with software such as VisiCalc, but also somewhat popular as a home computer. Initially only available in the US, but would eventually be available worldwide.
Commodore PET 6502 1977Most popular as an educational computer used in schools, but some success as a business or academic workstation too. Later, the PET would eventually see limited popularity in Europe.
ECD Micromind MOS Technology 6512 1977
Ohio Scientific Model 50065021978
Exidy Sorcerer Z801978
Atlacatl Home Computer MOS Technology 6502 1979A Salvadoran-made microcomputer based in locally sourced (from Texas Instruments Soyapango factory) processors at 2 MHz, TMC0280 Voice synthesizer, TMS9918 Video Interface with genlock capability and starting at 32 KB of DRAM, originally announced in January 1979 and launched after several delays in manufacturing in Christmas season of that year, proved popular in the country mostly with their Atlacatl Monica accounting software and TV-compatible output with genlock capabilities was used extensively by low-budget TV stations in Central America until around 1985; the company went bankrupt in 1989 after the end of draconian import regulations.
Explorer/85 80851979
ComPAN 8 1980Designed in the Institute of Industry Automation Systems PAN in Gliwice and produced in the MERA-ELZAB factory in Zabrze. [16] [17]

See also

Related Research Articles

<span class="mw-page-title-main">Intel 8080</span> 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, with common instructions using 4, 5, 7, 10, or 11 cycles. As a result, the processor is able to execute several hundred thousand instructions per second. Two faster variants, the 8080A-1 and 8080A-2, became available later with clock frequency limits of 3.125 MHz and 2.63 MHz respectively. The 8080 needs two support chips to function in most applications: the i8224 clock generator/driver and the i8228 bus controller. It is implemented in N-type metal–oxide–semiconductor logic (NMOS) using non-saturated enhancement mode transistors as loads thus demanding a +12 V and a −5 V voltage in addition to the main transistor–transistor logic (TTL) compatible +5 V.

<span class="mw-page-title-main">Motorola 6800</span> 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.

<span class="mw-page-title-main">Microcomputer</span> Small computer with a CPU made out of a microprocessor

A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a 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. An early use of the term "personal computer" in 1962 predates microprocessor-based designs. (See "Personal Computer: Computers at Companies" reference below). A "microcomputer" used as an embedded control system may have no human-readable input and output devices. "Personal computer" may be used generically or may denote an IBM PC compatible machine.

<span class="mw-page-title-main">Intel 8008</span> 8-bit microprocessor

The Intel 8008 is an early 8-bit microprocessor capable of addressing 16 KB of memory, introduced in April 1972. The 8008 architecture was designed by Computer Terminal Corporation (CTC) and was implemented and manufactured by Intel. While the 8008 was originally designed for use in CTC's Datapoint 2200 programmable terminal, an agreement between CTC and Intel permitted Intel to market the chip to other customers after Seiko expressed an interest in using it for a calculator.

<span class="mw-page-title-main">Altair 8800</span> Microcomputer designed in 1974

The Altair 8800 is a microcomputer designed in 1974 by MITS and based on the Intel 8080 CPU. Interest grew quickly after it was featured on the cover of the January 1975 issue of Popular Electronics and was sold by mail order through advertisements there, in Radio-Electronics, and in other hobbyist magazines. According to Harry Garland, the Altair 8800 was the product that catalyzed the microcomputer revolution of the 1970s. It was the first commercially successful personal computer. The computer bus designed for the Altair was to become a de facto standard in the form of the S-100 bus, and the first programming language for the machine was Microsoft's founding product, Altair BASIC.

<span class="mw-page-title-main">S-100 bus</span> Early computer bus

The S-100 bus or Altair bus, IEEE 696-1983(withdrawn), is an early computer bus designed in 1974 as a part of the Altair 8800. The S-100 bus was the first industry standard expansion bus for the microcomputer industry. S-100 computers, consisting of processor and peripheral cards, were produced by a number of manufacturers. The S-100 bus formed the basis for homebrew computers whose builders implemented drivers for CP/M and MP/M. These S-100 microcomputers ran the gamut from hobbyist toy to small business workstation and were common in early home computers until the advent of the IBM PC.

<span class="mw-page-title-main">History of computing hardware (1960s–present)</span>

The history of computing hardware starting at 1960 is marked by the conversion from vacuum tube to solid-state devices such as transistors and then integrated circuit (IC) chips. Around 1953 to 1959, discrete transistors started being considered sufficiently reliable and economical that they made further vacuum tube computers uncompetitive. Metal–oxide–semiconductor (MOS) large-scale integration (LSI) technology subsequently led to the development of semiconductor memory in the mid-to-late 1960s and then the microprocessor in the early 1970s. This led to primary computer memory moving away from magnetic-core memory devices to solid-state static and dynamic semiconductor memory, which greatly reduced the cost, size, and power consumption of computers. These advances led to the miniaturized personal computer (PC) in the 1970s, starting with home computers and desktop computers, followed by laptops and then mobile computers over the next several decades.

Micro Instrumentation and Telemetry Systems (MITS) was an American electronics company founded in Albuquerque, New Mexico that began manufacturing electronic calculators in 1971 and personal computers in 1975.

<span class="mw-page-title-main">Microsystems International</span>

Microsystems International Limited (MIL) was a telecommunications microelectronics company based in Ottawa, Ontario, Canada, founded in 1969. MIL was an early attempt to create a merchant semiconductor house by Nortel Networks.

<span class="mw-page-title-main">Kenbak-1</span> Personal computer, invented in 1970

The Kenbak-1 is considered by the Computer History Museum, the Computer Museum of America and the American Computer Museum to be the world's first "personal computer", invented by John Blankenbaker of Kenbak Corporation in 1970 and first sold in early 1971. Less than 50 machines were ever built, using Bud Industries enclosures as a housing. The system first sold for US$750. Today, only 14 machines are known to exist worldwide, in the hands of various collectors and museums. Production of the Kenbak-1 stopped in 1973, as Kenbak failed and was taken over by CTI Education Products, Inc. CTI rebranded the inventory and renamed it the 5050, though sales remained elusive.

<span class="mw-page-title-main">Processor Technology</span> Personal computer company, founded 1975

Processor Technology Corporation was a personal computer company founded in April 1975, by Gary Ingram and Bob Marsh in Berkeley, California. Their first product was a 4K byte RAM board that was compatible with the MITS Altair 8800 computer but more reliable than the MITS board. This was followed by a series of memory and I/O boards including a video display module.

<span class="mw-page-title-main">TV Typewriter</span>

The TV Typewriter is a video terminal that could display two pages of 16 lines of 32 upper case characters on a standard television set. The design, by Don Lancaster, appeared on the cover of Radio-Electronics magazine in September 1973.

<span class="mw-page-title-main">Microprocessor development board</span> Type of printed circuit board

A microprocessor development board is a printed circuit board containing a microprocessor and the minimal support logic needed for an electronic engineer or any person who wants to become acquainted with the microprocessor on the board and to learn to program it. It also served users of the microprocessor as a method to prototype applications in products.

<span class="mw-page-title-main">History of personal computers</span> History of the consumer personal computer

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.

<span class="mw-page-title-main">Heathkit H8</span> 1970s microcomputer

Heathkit's H8 is an Intel 8080A-based microcomputer sold in kit form starting in 1977. The H8 is similar to the S-100 bus computers of the era, and like those machines is often used with the CP/M operating system on floppy disk.

<span class="mw-page-title-main">Cromemco Dazzler</span>

The Cromemco Dazzler was a graphics card for S-100 bus computers introduced in a Popular Electronics cover story in 1976. It was the first color graphics card available for microcomputers. The Dazzler was the first of a succession of increasingly capable graphics products from Cromemco which, by 1984, were in use at 80% of all television stations in the U.S. for the display of weather, news, and sports graphics.

PolyMorphic Systems was a manufacturer of microcomputer boards and systems based on the S-100 bus. Their products included the Poly-88 and the System 8813. The company was incorporated in California in 1976 as Interactive Products Corporation d/b/a PolyMorphic Systems. It was initially based in Goleta, then Santa Barbara, California.

<span class="mw-page-title-main">Intellec</span>

The Intellec computers were a series of early microcomputers Intel produced in the 1970s as a development platform for their processors. The Intellec computers were among the first microcomputers ever sold, predating the Altair 8800 by at least two years.

Comp-Sultants, Inc. was an American computer company based in Huntsville, Alabama, active from 1969 to 1977. In 1975, the company released the Micro 440, a microcomputer based on the Intel 4040 microprocessor. It was, by Byte magazine's estimation, the first computer based on that chip.

References

  1. p. 4/3, A history of the personal computer: the people and the technology, Roy A. Allan, 2001, ISBN   0-9689108-0-7.
  2. Department of Physics (2008-10-06). "Machine code programming". Second Year Physics Laboratory Manual 2008/2009 (PDF). University of London. p. 54. Retrieved 2011-03-03.
  3. p. 4/8, A history of the personal computer: the people and the technology, Roy A. Allan, 2001, ISBN   0-9689108-0-7.
  4. http://www.nvg.ntnu.no/sinclair/computers/mk14/mk14_pe0579.htm "Science of Cambridge MK14", May 1979, retrieved 2011 July 2
  5. Microbee computer, From:Owen Hill Date:24 Aug 1998, Link list on Australian network policy and communications
  6. "The Byte Attic: Q1™". 2022-09-08.
  7. Zbigniew Stachniak, "The MIL MF7114 Microprocessor", IEEE Annals of Computer History, 22 September 2009, pg. 48-59
  8. "MIL CPS-1 Emulator". York University Computer Museum. 2023. Retrieved 2024-02-03. The CPS-1 computer was developed by Micosystems International Ltd. (MIL) of Ottawa between 1972 and 1973. The CPS-1 was powered by Canada's first microprocessor — the MIL 7114. This computer is one of the world's first commercially available microprocessor-based computer.
  9. Computer History Museum
  10. "SMP80/X series-Computer Museum".
  11. Zbigniew Stachniak. "The Making of the MCM/70 Microcomputer". IEEE Annals of the History of Computing, 2003: pg. 62-75
  12. Historielaget Grefsen-Kjelsås-Nydalen (2012-11-20). "En norsk datahistorie fra Kjelsås".
  13. "Tandberg Data Newsletter, Vol.5 Nr.1" (Document). Tandberg Data. June 1982. p. 4.
  14. "Siemens Intern, 1979 Nr.3" (Document). Siemens A/S. 1979-10-09. p. 8.
  15. Komputery - www.nfsk.prv.pl - Notatnik Fana Starych Komputerów Archived 2008-03-02 at the Wayback Machine
  16. Polish Computers Fan Site
Notes