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Minicomputers are a largely obsolete class of multi-user computers
which made up the middle range of the computing spectrum, in between the largest multi-user systems (mainframe computers) and the smallest single-user systems (microcomputers or personal computers)
History
The term evolved in the 1960s to describe the "small" Third Generation computers that
became possible with the use of the newly invented integrated
circuit technology. They usually took up one or a few cabinets, compared with mainframes that would usually fill a room. The first successful minicomputer was Digital Equipment Corporation's 12-bit PDP-8, which cost from US$16,000 upwards when launched in 1964.
As microcomputers developed in the 1970s and 80s, minicomputers filled the mid-range area between low powered microcomputers and high capacity mainframes. At the
time microcomputers were single-user, relatively simple machines running simple program-launcher operating systems like CP/M or DOS, while minis were
much more powerful systems that ran full multi-user, multitasking operating systems like VMS and Unix. The classical mini was a 16-bit computer, while the emerging higher performance 32-bit minis were often referred to as superminis.
Today at the turn of the millennium few minicomputers are still in use, having been overtaken by Fourth Generation computers
built using a more robust version of the microprocessor technology that
is used in personal computers. These are referred to as "servers", taking the name from
the server software that they run (typically file server and back-end database software, including email and web server software).
The decline of the minis happened due to the lower cost of microprocessor based hardware, the emergence of inexpensive and easily deployable local area network systems, and the desire of end-users to be less reliant on inflexible minicomputer
manufacturers and IT departments / "data centers" – with the result that minicomputers and dumb terminals were replaced by networked workstations and PCs in the latter half of the
1980s.
During the 1990s the change from minicomputers to inexpensive PC networks was cemented
by the development of several versions of Unix to run on the Intel x86 microprocessor architecture, including Solaris, Linux and FreeBSD/NetBSD. Also, the Microsoft Windows series of operating systems
now includes server versions that support preemptive multitasking and other features required for servers, beginning with
Windows NT. Significantly, Windows NT was written largely by designers from
DEC who were responsible for the DEC VMS operating system, originally developed for the VAX minicomputer range in the 1970s.
Impact
Several pioneering computer companies first built minicomputers, such as DEC, Data General, and Hewlett-Packard (HP) (who now
refers to its HP3000 minicomputers as "servers" rather than "minicomputers"). And although today's PCs and servers are clearly
microcomputers physically, architecturally their CPUs and operating systems have evolved largely by integrating features from
minicomputers.
See also:
List of minicomputers
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