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IBM System/3, a midrange computer introduced in 1969

Midrange computers, or midrange systems, were a class of computer systems that fell in between mainframe computers and microcomputers.[1][failed verification]

This class of machine emerged in the 1960s, with models from Digital Equipment Corporation (PDP line), Data General (NOVA), Hewlett-Packard (HP3000) widely used in science and research as well as for business - and referred to as minicomputers.[2][disputed ]

IBM favored the term "midrange computer" for their comparable, but more business-oriented systems.[3]

The S/38 (without case), the S/36, and the S/34 systems

IBM midrange systems


The main similarity of midrange computers and mainframes is that they are both oriented for decimal-precision computing[citation needed] and high volume input and output (I/O), but most midrange computers have an (reduced and specially designed) internal architecture with limited compatibility to mainframes. The low-end mainframe can be more affordable and less powerful that a hi-end midrange system, but midrange system still was a "replacement solution" with another service process, different OS and internal architecture.

The difference between similar-size midrange computers and superminis/minicomputers is the purpose for which they're used - supers/minis are oriented towards floating-point scientific computing, and midrange computers are oriented towards decimal business-oriented computing - but without clear distinction border between classes.

The earliest midrange computers was a single-user business calculation machines. Virtualization, typical feature of mainframes since 1972 (partially from 1965), was ported to midrange systems only in 1977; multi-user support was added to midranges in 1976 instead of 1972 for mainframes (but that's still a significantly earlier that a limited release of x86 virtualization (1985/87) or multi-user support (1983)[6]).

The latest midrange systems are primarily mid-class multi-user local network servers[7] that can handle the large-scale processing of many business applications. Although not as powerful and reliably as full-size mainframe computers, they are less costly to buy, operate, and maintain than mainframe systems and thus meet the computing needs of many organizations. Midrange systems was relatively popular as powerful network servers to help manage large Internet Web sites, but more oriented for corporate intranets and extranets, and other networks. Today, midrange systems include servers used in industrial process-control and manufacturing plants and play major roles in computer-aided manufacturing (CAM). They can also take the form of powerful technical workstations for computer-aided design (CAD) and other computation and graphics-intensive applications. Midrange system are also used as front-end servers to assist mainframe computers in telecommunications processing and network management.

Since the end of 1980s, when the client–server model of computing became predominant, computers of the comparable class are instead usually known as workgroup servers[8] and online transaction processing servers to recognize that they usually "serve" end users at their "client" computers. For the 1990-2000's, in some non-critical cases both lines were replaced by web servers, oriented for working with global network, but with less security background,[9] and mainly based using General purpose architecture (currently x86 or ARM).

See also


  1. ^ Estabrooks, Maurice (1995). Electronic technology, corporate strategy, and world transformation. Westport, Conn.: Quorum Books. p. 53. ISBN 0899309690.
  2. ^ Bell, Gordon (9 January 2015). "Rise and Fall of Minicomputers". Engineering and Technology History Wiki. Archived from the original on 5 April 2017. Retrieved 28 January 2017.
  3. ^ "1969 IBM System/3 promotional ad - midrange, minicomputer, Computer History, RPG". Computer History Archives Project. Netherlands. Archived from the original on 2021-12-14.
  4. ^ "IBM System/3 announcement" (PDF).
  5. ^ "IBM System/32". IBM Corporation. 23 January 2003.
  6. ^ Digital Research (1984). "PC-Mode bridges CP/M and PC DOS". Digital Dialogue - Employee Newsletter of Digital Research Inc. 3 (1): 3. Archived (PDF) from the original on 2017-01-04. Retrieved 2017-01-03.
  7. ^ "PC Magazine, Definition of: midrange computer".
  8. ^ "now referred to as small or midsize servers." "Minicomputer".
  9. ^ "Channel Surfing: IBM Brings One Voice to Server Group Reseller Channel". Enterprise System Journal.