Digital Equipment Corporation (DEC) PDP-8 on display at the National Museum of American History
Data General Nova, serial number 1, on display at the Computer History Museum
A PDP-11, model 40, an early member of DECs 16-bit minicomputer family, on display at the Vienna Technical Museum

Class of smaller general purpose computers that developed in the mid-1960s and sold for much less than mainframe and mid-size computers from IBM and its direct competitors.

- Minicomputer

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Digital Equipment Corporation

Major American company in the computer industry from the 1960s to the 1990s.

Original Digital Equipment Corporation logo designed by Elliot Hendrickson in 1957, used from 1957 to 1993
DEC VAXstation
DECUS - Logo Digital Equipment Corporation Users Society

Although the company produced many different product lines over its history, it is best known for the work in the minicomputer market starting in the mid-1960s.

Central processing unit

Electronic circuitry that executes instructions comprising a computer program.

EDVAC, one of the first stored-program computers
IBM PowerPC 604e processor
Fujitsu board with SPARC64 VIIIfx processors
CPU, core memory and external bus interface of a DEC PDP-8/I, made of medium-scale integrated circuits
Inside of laptop, with CPU removed from socket
Block diagram of a basic uniprocessor-CPU computer. Black lines indicate data flow, whereas red lines indicate control flow; arrows indicate flow directions.
Symbolic representation of an ALU and its input and output signals
A six-bit word containing the binary encoded representation of decimal value 40. Most modern CPUs employ word sizes that are a power of two, for example 8, 16, 32 or 64 bits.
Model of a subscalar CPU, in which it takes fifteen clock cycles to complete three instructions
Basic five-stage pipeline. In the best case scenario, this pipeline can sustain a completion rate of one instruction per clock cycle.
A simple superscalar pipeline. By fetching and dispatching two instructions at a time, a maximum of two instructions per clock cycle can be completed.

This standardization began in the era of discrete transistor mainframes and minicomputers and has rapidly accelerated with the popularization of the integrated circuit (IC).


A PDP-8 on display at The National Museum of Computing in Bletchley, England. This example is from the first generation of PDP-8s, built with discrete transistors and later known as the Straight 8.
A PDP-8 on display at The National Museum of Computing in Bletchley, England. This example is from the first generation of PDP-8s, built with discrete transistors and later known as the Straight 8.
An open PDP-8/E with its logic modules behind the front panel and one dual TU56 DECtape drive at the top
A "Straight-8" running at the Stuttgart Computer Museum
PDP-8/e at the Living Computers Museum.
PDP-8/I core memory stack
One of three inter-connected modules that make up a PDP-8 core memory plane.
One of three inter-connected modules that make up a PDP-8 core memory plane. This is the middle of the three and contains the array of actual ferrite cores.
One of three inter-connected modules that make up a PDP-8 core memory plane.

The PDP-8 is a 12-bit minicomputer that was produced by Digital Equipment Corporation (DEC).


A PDP-11/40 CPU is at the bottom, with a TU56 dual DECtape drive installed above it.
A PDP-11/40 CPU is at the bottom, with a TU56 dual DECtape drive installed above it.
PDP-11/03 (top right)
Original PDP-11/20 front panel
Original PDP-11/70 front panel
Later PDP-11/70 with disks and tape
PDP-11/03, cover removed to show the CPU board, with memory board beneath (two of the CPU chipset's four 40-pin packages have been removed, and the optional FPU is also missing)
The PDT-11/150 smart terminal system had two 8-inch floppy disc drives
DEC GT40 running Moonlander
MINC-23 laboratory computer
This Unimation robot arm controller used DEC LSI-11 series hardware
The DEC TU10 9-track tape drive was also offered on other DEC computer series
Q-Bus board with LSI-11/2 CPU
DEC "Fonz-11" (F11) Chipset
DEC "Jaws-11" (J11) Chipset

The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series.

Teletype Model 33

One of the first products to employ the newly-standardized ASCII code, which was first published in 1963.

Teletype Model 33 ASR teleprinter, with punched tape reader and punch, usable as a computer terminal
This 1974 advertisement emphasizes the widespread and longterm use of the Teletype Model 33
Teletype Model 33 ASR teleprinter keyboard with punched tape reader and punch. The left-front unit is the tape reader with its three-position START/STOP/FREE lever in the STOP position. A less-common tape reader had a four-position START/AUTO/STOP/FREE lever. In the AUTO position it could be commanded on and off remotely. The tape punch is the unit directly behind the reader. As it exits the machine, the tape passes under a triangular lip that allows the tape to be easily torn by lifting against the sharp edge of the lip.
The Model 33 ASR keyboard supported an upper-case-only ASCII character subset
Model 32, used for Telex service, had a three-row keyboard and narrower, five-hole paper tape.
Model 35 ASR, at the Living Computer Museum in Seattle
Model 33 ASR in use in 1978
Paper tape punch and reader visible in foreground
Rear of unit, with bell and answer back drum to left of motor
Fully-exposed mechanism

Because of its low price and ASCII-compatibility, the Model 33 was widely used with early minicomputers, and the large numbers of the teleprinter which were sold strongly influenced several de facto standards which developed during the 1960s and 1970s.

Data General

Early Data General advertisement, featuring manufacturing VP Harvey Newquist.

Data General was one of the first minicomputer firms of the late 1960s.

Mainframe computer

Computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise resource planning, and large-scale transaction processing.

A single-frame IBM z15 mainframe. Larger capacity models can have up to four total frames. This model has blue accents, as compared with the LinuxONE III model with orange highlights.
A pair of IBM mainframes. On the left is the IBM z Systems z13. On the right is the IBM LinuxONE Rockhopper.
An IBM System z9 mainframe
Inside an IBM System z9 mainframe
Operator's console for an IBM 701

A mainframe computer is large but not as large as a supercomputer and has more processing power than some other classes of computers, such as minicomputers, servers, workstations, and personal computers.


Series of computers featuring a 32-bit instruction set architecture and virtual memory that was developed and sold by Digital Equipment Corporation (DEC) in the late 20th century.

Stylized "VAX/VMS" used by Digital
VAX 8350 front view with cover removed
MicroVAX 3600 (left) with printer (right)
The SPEC-1 VAX, a VAX 11/780 used for benchmarking, showing internals

VAX was designed as a successor to the 16-bit PDP-11, one of the most successful minicomputers in history with approximately 600,000 examples sold.


Discontinued computer network operating system developed by Novell, Inc. It initially used cooperative multitasking to run various services on a personal computer, using the IPX network protocol.

A networking card with a sticker indicating certification with NetWare
Packages of NetWare 2.0
A book on NetWare published in Thai
NetWare 4 and NDS were the subjects of many technical sessions at the Novell BrainShare conference, here seen during a break in 1995
The success of NetWare as a product is what allowed Novell to have sales-related offices around the world, as the back side of this mid-1990s Novell presentation folder shows

From the beginning NetWare implemented a number of features inspired by mainframe and minicomputer systems that were not available in its competitors' products.


Family of general-purpose, high-level programming languages designed for ease of use.

The HP 2000 system was designed to run time-shared BASIC as its primary task.
Commodore BASIC v2.0 on the Commodore 64
MSX BASIC version 3.0
"Train Basic every day!"—reads a poster (bottom center) in a Russian school (c. 1985–1986)
IBM Cassette BASIC 1.10
Three modern Basic variants: Mono Basic, Basic and Gambas
BASIC came to some video game systems, such as the Nintendo Famicom.

This general model became very popular on minicomputer systems like the PDP-11 and Data General Nova in the late 1960s and early 1970s.