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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.
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.
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.
Model | Processor | Year | Format | Remarks | Ref |
---|---|---|---|---|---|
Intel SIM4-01, SIM4-02 | Intel 4004 | 1971 | bare board | Intel's developer kit for the 4004. Sold as the "MCS-4 Micro Computer Set". | [2] [3] |
Intel SIM8-01 | Intel 8008 | 1972 | bare board | Intel's developer kit for the 8008. Sold as the "MCS-8 Micro Computer Set". | [4] [5] |
MOS Technology KIM-1 | MOS Technology 6502 | 1975 | complete board | MOS's developer kit for the 6502, widely used in a number of projects | |
Motorola MEK6800D2 | Motorola 6800 | 1976 | complete board | ||
MPT8080 Microtutor | Intel 8080 | 1977 | complete board | A trainer type single-board-computer. As recently as 2008, it remained in academic use. | [6] As of 2011, the MPT8080 was still available for sale. |
Rockwell AIM-65 | 6502 | 1978 | complete board | ||
Synertek SYM-1 | 6502 | 1978 | complete board | ||
Intel SDK-85 | Intel 8085 | 1978 | |||
Tesla PMI-80 | Intel 8080 clone | 1982 | complete board | A czechoslovakian single-board microcomputer. |
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.
Model | Processor | Year | Format | Remarks | Ref |
---|---|---|---|---|---|
Comstar Star System 4 | Intel 4004 | 1972 | PCB and several chips/cards; optionally expandable | Intended for embedded/industrial applications which did not merit a minicomputer. A complete basic system included one PROM board and chip, one RAM board and chip, a CPU module, digital I/O board, power supply, and mounting rack; altogether for $995. Was in use by November 1972 in a paper tape editing system. | [7] [8] [9] |
SCELBI | Intel 8008 | 1974 | Was the earliest commercial kit computer based on the Intel 8008 microprocessor. Sold for embedded control applications. | [10] | |
Mark-8 | Intel 8008 | 1974 | Plans published; an etched board was available but constructors had to source all parts | [11] | |
MITS Altair 8800 | Intel 8080 | 1975 | Etched boards and parts | Introduced S-100 bus | |
IMSAI 8080 | Intel 8080 | 1975 | |||
Comp-Sultants Micro 440 | Intel 4040 | 1975 | First 4040-based micro | ||
SWTPC 6800 | Motorola 6800 | 1975 | Introduced SS-50 bus | ||
COSMAC ELF | RCA 1802 | 1976 | |||
Apple I | MOS Technology 6502 | 1976 | Assembled PCB; buyer supplied rest of components | ||
Nascom, Nascom 1 | Zilog Z80 | 1977 | |||
Nascom 2 | Z80 | 1979 | |||
Telmac 1800 | RCA 1802 | 1977 | |||
Newbear 77-68 | Motorola 6800 | 1977 | |||
Heathkit H8 | Intel 8080 | 1977 | All parts, case and power supply, detailed instructions | Heathkit was a notable manufacturer of electronics kits | |
Heathkit H11 | LSI-11 | 1977 | All parts, case and power supply, detailed instructions | A 16-bit microcomputer compatible with a PDP-11 | |
Electronics Australia 77up2 aka "Baby 2650" | Signetics 2650 | 1977 | |||
Netronics ELF II | RCA 1802 | 1977 | |||
Quest SuperELF | RCA 1802 | 1978 | [12] | ||
Elektor TV Games Computer | Signetics 2650 | 1979 | |||
System 68 | Motorola 6800 | 1977 | Electronics Today International magazine project | ||
PSI comp 80 | Z80 | 1979 | By Powertran from a design in the magazine Wireless World | ||
Science of Cambridge MK14 | National Semiconductor SC/MP | 1978 | Low-cost kit expandable to video output | [13] | |
Acorn System 1 | 6502 | 1979 | |||
Tangerine Microtan 65 | 6502 | 1979 | Rack-based extendible system | ||
Compukit UK101 | 6502 | 1979 | Practical Electronics magazine project (clone of Ohio Scientific Superboard II) | BASIC in ROM | |
Sinclair ZX80 | Z80 | 1980 | Among the last popular kit systems | ||
Sinclair ZX81 | Z80 | 1981 | Among the last popular kit systems | ||
MicroBee | Zilog Z80 | 1982 | The computer was conceived as a kit, with assembly instructions included in Your Computer magazine, in February 1982. | [14] | |
The Digital Group | Zilog Z80 | 1975 | Kits or assembled PCBs. Including cases from 1978 | The 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. |
A number of complete microcomputers were offered even before kits became popular, dating to as far back as 1972. 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.
Model | Processor | Year | Remarks | Ref |
---|---|---|---|---|
Q1 Corp. Q1 | Intel 8008 | 1972 | The first general purpose microcomputer to ship with a built in alphanumeric user interface. First delivered on December 11th, 1972. | [15] [16] |
Omni Electronics Omni 700 | Intel 4004 or 8008 | 1972 | Typewriter-sized general-purpose data processing machine introduced sometime before 1973. Also used Intel's PROM and RAM chips. | [9] |
MicroSystems International CPS-1 | MIL MF7114 | 1972 | Using a locally produced microprocessor based on the design of the Intel 4004. First built in 1972, a small number shipped in early 1973. | [17] [18] |
Micral N | Intel 8008 [19] | 1973 | Awarded the title of "the first personal computer using a microprocessor" by a panel at the Computer History Museum in 1986. | [20] |
Q1 Corp. Q1/Lite | Intel 8080 | 1974 | The first computer to ship with the Intel 8080 microprocessor in April 1974 (as a pre-production unit) and one of the first commercially available computers with the 8080 in June 1974 (first production units shipped August 1974). Also included a built-in printer and early flat-panel plasma display. | [16] [21] |
Sord Computer Corporation SMP80/08 | Intel 8008 | 1974 | Was 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. | [22] |
MCM/70 | Intel 8008 | 1974 | Primarily designed to run APL. According to the IEEE Annals of Computer History, the MCM/70 is the earliest commercial, non-kit personal computer. | [23] |
IBM 5100 | 1975 | An early portable computer with integrated monitor; the 5100 was possibly one of the first portable microcomputers using a CRT display. | ||
Sphere 1 | 1975 | A 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 | 1976 | Offered both as kit and assembled, but the vast majority were sold assembled. | ||
Tandberg Radiofrabrikk/Tandberg Data TDV-2114 | Intel 8080 | 1976 | One 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. | [24] [25] [26] |
Radio Shack TRS-80 | Zilog Z80 | 1977 | Mainly targeting North America, it was very popular as a home computer. | |
Apple II | 6502 | 1977 | Quickly 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 | 1977 | Most 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 500 | 6502 | 1978 | ||
Exidy Sorcerer | Z80 | 1978 | ||
Explorer/85 | 8085 | 1979 | ||
ComPAN 8 | 1980 | Designed in the Institute of Industry Automation Systems PAN in Gliwice and produced in the MERA-ELZAB factory in Zabrze. | [27] [28] |
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 clock 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. The 8080 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.
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.
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.
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.
The KIM-1, short for Keyboard Input Monitor, is a small 6502-based single-board computer developed and produced by MOS Technology, Inc. and launched in 1976. It was very successful in that period, due to its low price and easy-access expandability.
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.
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.
The IMSAI 8080 is an early microcomputer released in late 1975, based on the Intel 8080 and S-100 bus. It is a clone of its main competitor, the earlier MITS Altair 8800. The IMSAI is largely regarded as the first "clone" microcomputer. The IMSAI machine runs a highly modified version of the CP/M operating system called IMDOS. It was developed, manufactured and sold by IMS Associates, Inc.. In total, between 17,000 and 20,000 units were produced from 1975 to 1978.
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.
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.
The MK14 was a computer kit sold by Science of Cambridge of the United Kingdom, first introduced in 1977 for £39.95. The price was very low for a complete computer system at the time, and Science of Cambridge eventually sold over fifteen thousand kits.
Micral is a series of microcomputers produced by the French company Réalisation d'Études Électroniques, beginning with the Micral N in early 1973. The Micral N was one of the first commercially available microprocessor-based computers.
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.
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.
Each time Intel launched a new microprocessor, they simultaneously provided a system development kit (SDK) allowing engineers, university students, and others to familiarise themselves with the new processor's concepts and features. The SDK single-board computers allowed the user to enter object code from a keyboard or upload it through a communication port, and then test run the code. The SDK boards provided a system monitor ROM to operate the keyboard and other interfaces. Kits varied in their specific features but generally offered optional memory and interface configurations, a serial terminal link, audio cassette storage, and EPROM program memory. Intel's Intellec development system could download code to the SDK boards.
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.
The Gigatron TTL is a retro-style 8-bit computer, where the CPU is implemented by a set of TTL chips instead of a single microprocessor, imitating the hardware present in early arcades. Its target is the computing enthusiasts, for studying or hobby purposes.
The Micro 440 was an early microcomputer released by Comp-Sultants, Inc.. Powered by an Intel 4040 microprocessor, it was, by Byte magazine's estimation, the first third-party computer based on that chip. It sold poorly, and the company folded after less than two years, although the Micro 440 found some popularity after its demise among hobbyists as a bare-bones chassis.
Q1 Corporation was an American computer company founded in 1969 by Daniel Alroy. Its main focus was the manufacturing and sale of early microcomputers.
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.