Minicomputer 20272 225829147 2008-07-15T16:19:33Z Epbr123 1395162 Reverted edits by [[Special:Contributions/OrgasGirl|OrgasGirl]] to last version by Traveler100 (using [[WP:HG|Huggle]]) [[Image:Pdp7-oslo-2005.jpeg|thumb|PDP 7]] '''Minicomputer''' (colloquially, '''mini''') is a largely obsolete term for a class of multi-user [[computer]]s that lies in the middle range of the computing spectrum, in between the largest [[multi-user systems]] ([[mainframe computer]]s) and the smallest single-user systems ([[microcomputer]]s or [[personal computers]]). Formerly this class formed a distinct group with its own hardware and operating systems notably having smaller address space (notice the cited numbers of bits in a data word, ranging from 8 to 24 bits commonly around 16-bits). While the distinction between mainframe computers and smaller computers remains fairly clear, contemporary middle-range computers are not well differentiated from personal computers, being typically just a more powerful but still compatible version of a personal computer. More modern terms for minicomputer-type machines include [[IBM midrange computer|midrange systems]] ([[IBM]] parlance), [[computer workstation|workstation]]s ([[Sun Microsystems]] and general [[Unix|UNIX]]/[[Linux]] parlance), and [[Server (computing)|server]]s. ==History== ===1960s: Origin; 1970s: Market entrenchment=== The term "mini computer" evolved in the 1960s to describe the “small” third generation computers that became possible with the use of [[transistor]] and [[core memory]] technologies. They usually took up one or a few cabinets the size of a large refrigerator or two, compared with [[mainframe computer|mainframes]] that would usually fill a room. The first successful minicomputer was [[Digital Equipment Corporation]]’s 12-bit [[PDP-8]], which cost from [[United States dollar|US$]]16,000 upwards when launched in 1964. The important precursors of the PDP-8 include the [[PDP-5]], [[LINC]], the [[TX-0]], the [[TX-2]], and the [[PDP-1]]. Digital Equipment gave rise to a number of minicomputer companies along [[Massachusetts Route 128]], including [[Data General]], [[Wang Laboratories]], [[Apollo Computer]], and [[Prime Computer]]. The [[7400 series]] of [[transistor-transistor logic|TTL]] [[integrated circuit]]s started appearing in minicomputers in the late 1960s. The [[74181]] [[arithmetic logic unit]] (ALU) was commonly used in the [[central processing unit|CPU]] data paths. Each 74181 had a bus width of four bits, hence the popularity of ''bit-slice'' architecture. The 7400 series offered data-selectors, [[multiplexer]]s, three-state buffers, memories, etc. in [[dual in-line package]]s with one-tenth inch spacing, making major system components and architecture evident to the naked eye. (Starting in the 1980s, many minicomputers used [[VLSI]] circuits (Very Large Scale Integration), often making the hardware organization much less apparent.) 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 [[CPM operating system|CP/M]] or [[MS-DOS]], while minis were much more powerful systems that ran full multi-user, multitasking operating systems like [[OpenVMS|VMS]] and [[Unix]], often with [[time-sharing|timesharing]] versions of [[BASIC]] for application development ([[MAI Basic Four]] systems being very popular in that regard). The classical mini was a [[16-bit]] computer, while the emerging higher performance [[32-bit]] minis were often referred to as [[supermini]]s. ===Mid-1980s, 1990s: The minis give way to the micros=== The decline of the minis happened due to the lower cost of microprocessor based [[computer hardware|hardware]], the emergence of inexpensive and easily deployable [[local area network]] systems, the emergence of the [[80286]] and the [[80386]] microprocessors, 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 terminal]]s were replaced by networked [[workstation]]s and [[server (computing)|server]]s and [[IBM PC compatible|PC]]s 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 [[computer architecture|architecture]], including [[Solaris (operating system)|Solaris]], [[FreeBSD]], [[NetBSD]] and [[OpenBSD]]. Also, the Microsoft Windows series of operating systems, beginning with [[Windows NT]], now includes server versions that support preemptive multitasking and other features required for servers. As [[microprocessor]]s have become more powerful, [[central processing unit|CPUs]] built up from multiple components—once the distinguishing feature differentiating mainframes and midrange systems from microcomputers—have become increasingly obsolete, even in the largest [[mainframe computer]]s. [[Digital Equipment Corporation]] was the leading minicomputer manufacturer, at one time the 2nd largest computer company after [[IBM]]. But as the minicomputer declined in the face of generic UNIX servers and Intel based PCs, not only DEC, but almost every other minicomputer company including [[Data General]], [[Prime Computer|Prime]], [[Computervision]], [[Honeywell]] and [[Wang Laboratories]], many based in [[New England]] also collapsed. DEC was sold to Compaq in 1998. ===The minicomputer’s industrial impact and heritage=== Several pioneering computer companies first built minicomputers, such as [[DEC]], [[Data General]], and [[Hewlett-Packard|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. In the software context, the relatively simple OSes for early microcomputers were usually inspired by minicomputer OSes (such as [[CP/M]]'s similarity to Digital's [[RSTS/E|RSTS]]) and multiuser OSs of today are often either inspired by or directly descended from minicomputer OSs ([[UNIX]] was originally a minicomputer OS, while [[Windows NT]] — the foundation for all current versions of [[Microsoft Windows]] — borrowed design ideas liberally from [[OpenVMS|VMS]] and UNIX). Many of the first generation of PC programmers were educated on minicomputer systems.{{Fact|date=April 2008}} ==List of some notable minicomputers== *[[Control Data]]’s [[CDC 160A]] and [[CDC 1700]] *[[Digital Equipment Corporation|DEC]] [[Programmed Data Processor|PDP]] and [[VAX]] series *[[Data General]] [[Data General Nova|Nova]] *[[Hewlett-Packard]] [[HP3000]] series, [[HP2100]] series, [[HP1000]] series. *[[Honeywell]]-[[Groupe Bull|Bull]] [[Level 6/DPS 6/DPS 6000]] series *[[IBM]] [[IBM midrange computer|midrange computer]]s *[[Norsk Data]] Nord-1, Nord-10, and Nord-100 *[[Prime Computer]] Prime 50 series *[[Scientific Data Systems|SDS]] SDS-92 *[[Wang Laboratories]] 2200 and VS series *[[K-202]], first Polish minicomputer ==See also== *''[[The Soul of a New Machine]]'' - about the development of Data General’s Eclipse/MV minicomputers in the early 1980s *[[Charles Babbage Institute]] *[[History of computing hardware (1960s-present)]] *[[Supermini]] ==External links== *[http://www.technikum29.de/en/computer/early-computers Early mini computers], still runnable in a German computer museum {{Computer sizes}} [[Category:Minicomputers|*Minicomputer]] [[Category:Classes of computers]] [[de:Minirechner]] [[es:Minicomputadora]] [[fa:رایانه کوچک]] [[ko:미니컴퓨터]] [[id:Komputer mini]] [[iu:ᖃᕆᑕᐅᔭᖅ ᐊᒥᓱᓯᐅᑦ/qaritaujaq amisusiut]] [[it:Minicomputer]] [[he:מיני-מחשב]] [[mk:Миникомпјутери]] [[nl:Minicomputer]] [[ja:ミニコンピュータ]] [[no:Minidatamaskin]] [[pl:Minikomputer]] [[pt:Minicomputador]] [[ru:Миникомпьютер]] [[fi:Minitietokone]] [[sv:Minidator]]