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.
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Before the advent of microprocessors, it was possible to build small scaled computers using small-scale integrated circuits. A small number of such kits were designed and offered.
As microprocessors were released into the market, companies often released simple development systems to bootstrap the use of the processor. These systems were often converted by hobbyists into complete computer systems.
Model | Processor | Year | Format | Remarks | Ref |
---|---|---|---|---|---|
Intel SIM8-01 | Intel 8008 | early 1972 | bare board | Intel's developer kit for the 8008 | |
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 | ||
Rockwell AIM-65 | 6502 | complete board | |||
Synertek SYM-1 | 6502 | 1978 | complete board | ||
Intel SDK-85 | Intel 8085 | 1978 |
For some time the microcomputer world was dominated by systems delivered in kit form. As most machines of the era were sold in small numbers, there was no reason to invest in automated manufacturing systems, leaving the final assembly to manual labor. Kits took advantage of this by offering the system at a low price point, and relying on the user to complete the expensive part, the final assembly. Kits were popular between 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 famed ZX81 is among the last of the large sellers in the kit market.
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 |
---|---|---|---|---|---|
SCELBI | Intel 8008 | 1974 | was the earliest commercial kit computer based on the Intel 8008 microprocessor. sold for embedded control applications. | [2] | |
Mark-8 | Intel 8008 | 1974 | Plans published, an etched board was available but constructors had to source all parts | [3] | |
MITS Altair 8800 | Intel 8080 | 1975 | Etched boards and parts | introduced S-100 bus | |
COSMAC ELF | RCA 1802 | 1976 | |||
Apple I | MOS Technology 6502 | 1976 | |||
Nascom, Nascom 1 | Zilog Z80 | 1977 | |||
Nascom 2 | Z80 | 1979 | |||
Newbear 77-68 | Motorola 6800 | 1977 | |||
Heathkit H8 | 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 | 2650 | 1977 | |||
Netronics ELF II | RCA 1802 | 1977 | |||
Quest SuperELF | RCA 1802 | ||||
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 | [4] | |
Tangerine Microtan 65 | 6502 | 1979 | Rack-based extendible system | ||
Sinclair's ZX80 | Z80 | 1980 | were among the last popular kit systems | ||
Sinclair ZX81 | Z80 | 1981 | were among the last popular kit systems |
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 market and led to the home computer revolution.