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.
| 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 | 1972 | bare board | Intel's developer kit for the 8008. Sold as the "MCS-8 Micro Computer Set". | [4] [5] | ||
| 1975 | complete board | MOS's developer kit for the 6502, widely used in a number of projects | ||||
| 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 | |||
| 6502 | 1978 | complete board | ||||
| Intel SDK-85 | 1978 | |||||
| Tesla PMI-80 | Intel 8080 clone | 1982 | complete board | A czechoslovakian |
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.
| Processor | Year | Format | Remarks | Ref | ||
| Comstar Star System 4 | Intel 4004(?) | 1972 | Some chips (not enough to fill all slots), etched boards, power supply, mounting rack (and enclosure available optionally); enough for a complete basic system | 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] | |
| Intel 8008 | 1974 | Was the earliest commercial kit computer based on the Intel 8008 microprocessor. Sold for embedded control applications. | [9] | |||
| Mark-8 | Intel 8008 | 1974 | Plans published; an etched board was available but constructors had to source all parts | [10] | ||
| 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 | 1977 | |||||
| Nascom 2 | Z80 | 1979 | ||||
| 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 | |||
| Electronics Australia 77up2 aka "Baby 2650" | 1977 | |||||
| Netronics ELF II | RCA 1802 | 1977 | ||||
| Quest SuperELF | RCA 1802 | 1974 | ||||
| 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 | 1978 | Low-cost kit expandable to video output | [11] | |||
| 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 | |||
| Z80 | 1981 | Among the last popular kit systems | ||||
| Zilog Z80 | 1982 | The computer was conceived as a kit, with assembly instructions included in Your Computer magazine, in February 1982. | [12] | |||
| 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.
| Processor | Year | Remarks | Ref | ||
| Q1 Corporation, Q1 | Intel 8008 | 1972 | The first general purpose microcomputer to ship with a built in alphanumeric user interface. First sold on December 11th, 1972. | [13] [14] | |
| 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. | [15] [16] | |
| Micral N | Intel 8008 [17] | 1973 | Awarded the title of "the first personal computer using a microprocessor" by a panel at the Computer History Museum in 1986. | [18] | |
| 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. | [19] | |
| 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. | [20] | |
| 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. | [21] [22] [23] | |
| 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 | |||
| Atlacatl Home Computer | MOS Technology 6502 | 1979 | A 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 | 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. | [24] [25] |