Engineering: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.

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.

• The Kenbak-1 (1971) used small-scale integration transistor–transistor logic (TTL) ICs and had 256 bytes of memory. It was priced at USD 750 and sold only 40 units.
• Datapoint 2200 (shipped 1971) was the first machine designed to use a microprocessor, but when Intel could not deliver the 8008 in time, they released the machine using discrete logic.
• The Educ-8 (1975) was an Electronics Australia magazine project describing a computer built from TTL ICs.

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.

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
MPT8080 Microtutor	Intel 8080	1977	complete board	A trainer type single-board-computer. As recently as 2008, it remained in academic use.	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 czechoslovakiand 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.

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.
Mark-8	Intel 8008	1974	Plans published; an etched board was available but constructors had to source all parts
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	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	National Semiconductor SC/MP	1978		Low-cost kit expandable to video output
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.
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.

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.

Model	Processor	Year	Remarks	Ref
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.
Micral N		1973	Awarded the title of "the first personal computer using a microprocessor" by a panel at the Computer History Museum in 1986.
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.
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.
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 very 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.
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.

See also

• List of home computers
• List of home computers by video hardware
• Microprocessor development board
• Microcomputer Associates, Incorporated

References

Notes

• A cached copy of the Department of Physics (2008-10-06). "Machine code programming" can be found on the internet archive at:
  • https://web.archive.org/web/20100216174218/http://kcl.ac.uk/content/1/c6/02/14/60/2ndyearmanual2008-2009lab1.pdf
• "Timeline". Computer History.org. http://www.computerhistory.org/timeline/?year=1973. Retrieved 25 December 2007. 

External links

• Obsolete technology website — Information about many old computers.