List of early microcomputers
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. 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, where each IC contained only a few logic gates or flip-flops.- The Kenbak-1 used small scale integration transistor-transistor logic ICs and had 256 bytes of memory. It was priced at USD 750 and sold only 40 units.
- Datapoint 2200 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 was an Electronics Australia magazine project describing a computer built from TTL ICs.
Test and development machines
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 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 | - | - |
Kits
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. | inventors.about.com | |
| 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 | |
| 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 | 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 | ||
| Acorn System 1 | 6502 | 1979 | |||
| Tangerine Microtan 65 | 6502 | 1979 | Rack-based extendible system | ||
| Compukit UK101 | 6502 | 1979 | Practical Electronics magazine project | BASIC in ROM | |
| Sinclair's ZX80 | Z80 | 1980 | Were among the last popular kit systems | ||
| Sinclair ZX81 | Z80 | 1981 | Were 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. |
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 market and led to the home computer revolution.- MicroSystems International's CPS-1, 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 was awarded the title of "the first personal computer using a microprocessor by a panel at the Computer History Museum in 1986.
- Sord Computer Corporation's SMP80/08, based on the Intel 8008, 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 was a 1974 Intel 8008-based design, 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 was possibly the first portable microcomputer. Most people think the famous IBM PC was IBM's first micro but there were a number of microcomputer models released by IBM from 1975.
- Processor Technology's Sol-20, offered both as kit and assembled, but the vast majority were sold assembled
- ECD Micromind, introduced 1977 MOS Technology 6512. Prototypes only.
- MPT8080 Microtutor, an Intel 8080–based microprocessor trainer introduced 1977. As recently as 2008, it remained in academic use. As of 2011, the MPT8080 was still available for sale.
- Tesla PMI-80
- Ohio Scientific Model 500, 1978, 6502
- Exidy Sorcerer, 1978, Z80
- Explorer/85 8085, 1979
- ComPAN 8 was a Polish microcomputer in the 1980’s designed in the Institute of Industry Automation Systems PAN in Gliwice and produced in the MERA-ELZAB factory in Zabrze.