The term "minicomputer" developed in the 1960s[5] to describe the smaller computers that became possible with the use of transistors and core memory technologies, minimal instructions sets and less expensive peripherals such as the ubiquitous Teletype Model 33 ASR.
[7] Later minicomputers tended to be more compact, and while still distinct in terms of architecture and function, some models eventually shrunk to a similar size as large microcomputers.
Another common difference was that most earlier small machines were not "general purpose", in that they were designed for a specific role like process control or accounting.
[8] It meets most definitions of "mini" in terms of power and size, but was designed and built to be used as an instrumentation system in labs, not as a general-purpose computer.
[9] Many similar examples of small special-purpose machines exist from the early 1960s, including the UK Ferranti Argus and Soviet UM-1NKh.
However, its basic price of $100,000 (equivalent to $1,029,921 in 2023) and custom desk-like chassis places it within the "small system" or "midrange computer"[10] category as opposed to the more modern use of the term minicomputer.
Nevertheless, the CDC 160 remains a strong contender for the term "first minicomputer",[9] provided the Bendix G-15—an earlier compact vacuum tube machine—is excluded as non-transistorized.
[12] Smaller systems, including those from DEC like the PDP-5 and LINC,[13] had existed prior to this point, but it was the PDP-8 combination of small size, general purpose orientation and low price that puts it firmly within the modern definition.
Its success led to widespread imitation, and the creation of an entire industry of minicomputer companies along Massachusetts Route 128, including Data General, Wang Laboratories and Prime Computer.
The introduction and standardization of the 7-bit ASCII character set led to the move to 16-bit systems, with the late-1969 Data General Nova being a notable entry in this space.
In a 1970 survey, The New York Times had suggested a consensus definition of a minicomputer as a machine costing less than US$25,000 (equivalent to $196,000 in 2023[15]), with an input-output device such as a teleprinter and at least four thousand words of memory, that is capable of running programs in a higher level language, such as Fortran or BASIC.
The boom in worldwide seismic exploration for oil and gas in the early 1970s saw the widespread use of minicomputers in dedicated processing centres close to the data collection crews.
[18][19] At the launch of the MITS Altair 8800 in 1975, Radio Electronics magazine referred to the system as a "minicomputer", although the term microcomputer soon became usual for personal computers based on single-chip microprocessors.
But it was not long before this market also began to come under threat; the Motorola 68000 offered a significant percentage of the performance of a typical mini in a desktop platform.
Minis remained a force for those using existing software products or those who required high-performance multitasking, but the introduction of newer operating systems based on Unix began to yield highly practical replacements for these roles as well.
By the end of the decade all of the classic vendors were gone; Data General, Prime, Computervision, Honeywell, and Wang, failed, merged, or were bought out.
In contrast, competing proprietary computing architectures from the early 1980s, such as DEC's VAX, Wang VS, and Hewlett-Packard's HP 3000 have long been discontinued without a compatible upgrade path.
And although today's PCs and servers are clearly microcomputers physically, architecturally their CPUs and operating systems have developed largely by integrating features from minicomputers.