Midrange computer
| Industry | Computer hardware |
|---|---|
| Founded | 1969 |
| Headquarters | Armonk, New York , United States |
| Products | System/3, System/32, System/34, System/36, System/38, AS/400, eServer iSeries, IBM System i, IBM Power Systems |
Midrange computers, sometimes referred to as midrange systems, represent a category of computers that occupy the space between mainframe computers and microcomputers.
Originating in the 1960s, this group encompassed devices from manufacturers such as Digital Equipment Corporation (notably the PDP series), Data General (including the NOVA models), and Hewlett-Packard (with systems like the HP 2100 and HP 3000). These machines found widespread application across scientific research, commercial enterprises, and were frequently classified under the umbrella of minicomputers.
IBM coined the term "midrange computer" to define their line of business-oriented systems.
IBM midrange systems
- The System/3 (1969) marked IBM's initial entry into midrange computing.
- The System/32 (1975), also known as IBM 5320, was a 16-bit system designed for single users.
- Introduced in 1977, the System/34 replaced both the System/3 and System/32, featuring dual 16-bit processors and operating on the SSP OS.
- The System/38 (1979) brought innovations such as an integrated relational database management system (DBMS), 48-bit addressing capabilities, and ran the CPF operating system.
- Following the System/34's design and OS, the System/36 was launched in 1983.
- Debuted in 1988, the AS/400 later rebranded as eServer iSeries in 2000 and IBM System i in 2006, operates on the OS/400 platform.
- Announced in April 2008, the IBM Power Systems combined IBM System i and IBM System p into a unified architecture.
Positioning
Both midrange computers and mainframes emphasize decimal-precision processing alongside substantial input/output (I/O) throughput. However, midrange machines possess a more simplified internal design with limited compatibility with mainframe systems. While an entry-level mainframe may be less costly and less capable than a top-tier midrange machine, these midrange systems are positioned as alternative "replacement solutions," distinguished by their unique operating systems and architectures.
In comparison to supermini and minicomputers of similar scale, midrange computers primarily address decimal-based business computing needs, whereas supers and minis are generally oriented toward floating-point computations for scientific applications—though this separation is not absolute.
Initial midrange computers functioned as single-user business calculators. Virtualization technology, which had been standard in mainframes since 1972, was introduced to midrange platforms by 1977. Multi-user capabilities were established by 1976, predating virtualization on x86 platforms (1985/87) and multi-user support on them (1983).
Contemporary midrange systems mainly serve as mid-tier multi-user local network servers handling extensive business workloads. Although they do not match full-size mainframes in power or reliability, they offer significant cost advantages in acquisition, operation, and maintenance—fitting the requirements of many organizations. These systems have been widely adopted as servers for large corporate intranets, extranets, and Internet sites. Their roles also extend to industrial process control environments, manufacturing facilities including computer-aided manufacturing (CAM), as well as technical workstations supporting CAD and other graphics-intensive tasks. Furthermore, they function as front-end servers aiding mainframes in telecommunications processing and network administration.
Since the late 1980s with the emergence of client–server architectures, analogous systems have often been identified as workgroup servers or online transaction processing servers, reflecting their function in supporting end users through client devices. Throughout the 1990s and 2000s, many such responsibilities transitioned to web servers optimized for global connectivity but generally relying on general-purpose hardware platforms like x86 or ARM with comparatively reduced built-in security features.