Minicomputer

The term minicomputer names the now 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)

The term evolved in the 1960s to describe "small" server-class computers, usually taking up one or a few cabinets, compared with mainframes that would usually fill a room. They cost far less than mainframes.

As microcomputers developed in the 1970s and 80s, minicomputers filled the mid-range area between micros and mainframes. Microcomputers were single-user, relatively simple machines running simple program-launcher operating systems like CP/M or MS-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.

As of 2001, the term "minicomputer" is no longer used for the mid-range computer systems, most of which are now referred to simply as servers. This has come about as a result of several factors, including:

• dumb terminals were replaced by networked personal computers, and therefore, users no longer interacted directly with the "backend computers" - the programs run on their PC did.
• Several versions of Unix now run on the Intel architecture, including Solaris, Linux and FreeBSD.
• The Windows series of operating systems includes server versions that support multitasking and other features required for mid-range uses, beginning with Windows NT.
• Hewlett-Packard now refers to its HP3000 series of computers as "servers" rather than as "minicomputers".

A number of pioneering computer companies first built minicomputers, such as DEC, Data General, Hewlett-Packard, and IBM.

Today's personal computers are descendants of the microcomputers, but architecturally their CPUs and operating systems have evolved largely by integrating features from minicomputers.

The class of minicomputers includes:

• DEC PDP
• DEC VAX
• Data General Nova
• IBM AS400 and RS-6000
• HP 3000[?] Series
• Norsk Data Nord-1, Nord-10 and Nord-100
• Prime[?] 50-series[?]

See also History of computing