Midrange computers, or midrange systems, were a class of

computer A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...

systems that fell in between

mainframe computer A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise ...

s and microcomputers. This class of machine emerged in the 1960s, with models from

Digital Equipment Corporation Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until ...

( PDP lines),

Data General Data General Corporation was an early minicomputer firm formed in 1968. Three of the four founders were former employees of Digital Equipment Corporation (DEC). Their first product, 1969's Data General Nova, was a 16-bit minicomputer intended to ...

( NOVA), and

Hewlett-Packard The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company. It was founded by Bill Hewlett and David Packard in 1939 in a one-car garage in Palo Alto, California ...

(

HP 2100 The HP 2100 is a series of 16-bit minicomputers that were produced by Hewlett-Packard (HP) from the mid-1960s to early 1990s. Tens of thousands of machines in the series were sold over its 25-year lifetime, making HP the fourth-largest minicomp ...

and HP 3000) widely used in science and research as well as for business - and referred to as minicomputers. IBM favored the term "midrange computer" for their comparable, but more business-oriented systems.

IBM midrange systems

* System/3 (1969) was the first IBM midrange system. * System/32 (introduced in 1975) was a 16-bit single-user system also known as the IBM 5320. * System/34 (1977) was intended to be a successor to both the 3 and the 32. It had two 16-bit processors and ran the SSP operating system. * System/38 (1979) was the first midrange system to have an integrated

relational database management system A relational database (RDB) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. A Relational Database Management System (RDBMS) is a type of database management system that stores data in a structured for ...

(DBMS). The S/38 had 48-bit addressing, and ran the CPF

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

. * System/36 (1983) was a follow on to the System/34 with the same architecture and operating system. * AS/400 was introduced under that name in 1988, renamed eServer iSeries in 2000, and subsequently became the IBM System i in 2006. It runs the OS/400 operating system. * IBM Power Systems were introduced in April 2008, a convergence of IBM System i and IBM System p.

Positioning

The main similarity of midrange computers and mainframes is that they are both oriented for decimal-precision computing and high volume input and output (I/O), but most midrange computers have a reduced and specially designed internal architecture, with limited compatibility with mainframes. A low-end mainframe can be more affordable and less powerful than a high-end midrange system, but a midrange system is still 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 are used - supers/minis are oriented towards

floating-point In computing, floating-point arithmetic (FP) is arithmetic on subsets of real numbers formed by a ''significand'' (a Sign (mathematics), signed sequence of a fixed number of digits in some Radix, base) multiplied by an integer power of that ba ...

scientific computing, and midrange computers are oriented towards decimal business-oriented computing - but without a clear distinction border between classes. The earliest midrange computers were single-user business calculation machines. Virtualization, a typical feature of mainframes since 1972 (partially from 1965), was ported to midrange systems only in 1977; multi-user support was added to midrange systems in 1976 compared to 1972 for mainframes (but that's still significantly earlier than the limited release of x86 virtualization (1985/87) or multi-user support (1983)). The latest midrange systems are primarily mid-class multi-user local network servers that can handle the large-scale processing of many business applications. Although not as powerful and reliable 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 were 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 The client–server model is a distributed application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters, called clients. Often clients and servers communicate ov ...

of computing became predominant, computers of the comparable class are instead usually known as '' workgroup servers''"now referred to as small or midsize servers." and ''online transaction processing servers'' to recognize that they usually "serve" end users at their "client" computers. During the 1990s and 2000s, in some non-critical cases both lines were replaced by ''web servers'', oriented for working with global networks, but with less security background, and mainly using General purpose architectures (currently x86 or ARM).

References

{{DEFAULTSORT:Midrange Computer *Midrange

IBM midrange systems

Positioning

See also

References