
Regnecentralen (RC) was the first
Danish 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 ...
company, founded on 12 October 1955. Through the 1950s and 1960s, they designed a series of computers, originally for their own use, and later to be sold commercially. Descendants of these systems sold well into the 1980s. They also developed a series of high-speed
paper tape machines, and produced
Data General Nova machines under license.
Genesis
What would become RC began as an advisory board formed by the Danish ''Akademiet for de Tekniske Videnskaber'' (''Academy of Applied Sciences'') to keep abreast of developments in modern electronic
computing devices taking place in other countries. It was originally named Regnecentralen, Dansk Institut for Matematikmaskiner (''Danish Institute of Computing Machinery '') After several years in the advisory role, in 1952 they decided to form a computing
service bureau for Danish government, military and research uses. Led by Niels Ivar Bech, the group was also given the details of the
BESK machine being designed at the Swedish Mathematical Center (Matematikmaskinnämndens Arbetsgrupp).
The group decided to build their own version of the BESK to run the bureau, and formed Regnecentralen in October 1955 to complete and run the machine. The result was the
DASK, a
vacuum tube
A vacuum tube, electron tube, thermionic valve (British usage), or tube (North America) is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. It ...
-based machine that completed construction in 1956 and went into full operation in February 1957. DASK was followed in 1961 by the fully
transistor
A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electric power, power. It is one of the basic building blocks of modern electronics. It is composed of semicondu ...
ized GIER, used for similar tasks. GIER is an acronym for "
Geodætisk Instituts Elektroniske Regnemaskine" (Institute of Geodetics Electronic Calculator) and was introduced there on 14 September 1961. GIER proved to be a useful machine, and went on to be used at many Danish universities. Bech also sold GIER machines to the
Eastern Bloc
The Eastern Bloc, also known as the Communist Bloc (Combloc), the Socialist Bloc, the Workers Bloc, and the Soviet Bloc, was an unofficial coalition of communist states of Central and Eastern Europe, Asia, Africa, and Latin America that were a ...
nations, starting with
Czechoslovakia
Czechoslovakia ( ; Czech language, Czech and , ''Česko-Slovensko'') was a landlocked country in Central Europe, created in 1918, when it declared its independence from Austria-Hungary. In 1938, after the Munich Agreement, the Sudetenland beca ...
,
Hungary
Hungary is a landlocked country in Central Europe. Spanning much of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia and ...
,
Poland
Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...
and
Bulgaria
Bulgaria, officially the Republic of Bulgaria, is a country in Southeast Europe. It is situated on the eastern portion of the Balkans directly south of the Danube river and west of the Black Sea. Bulgaria is bordered by Greece and Turkey t ...
, and later
Romania
Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...
, the
East Germany
East Germany, officially known as the German Democratic Republic (GDR), was a country in Central Europe from Foundation of East Germany, its formation on 7 October 1949 until German reunification, its reunification with West Germany (FRG) on ...
, and
Yugoslavia
, common_name = Yugoslavia
, life_span = 1918–19921941–1945: World War II in Yugoslavia#Axis invasion and dismemberment of Yugoslavia, Axis occupation
, p1 = Kingdom of SerbiaSerbia
, flag_p ...
.
RC was also home to
Peter Naur
Peter Naur (25 October 1928 – 3 January 2016) was a Danish computer science pioneer and 2005 Turing Award winner. He is best remembered as a contributor, with John Backus, to the Backus–Naur form (BNF) notation used in describing the syntax ...
, and DASK and GIER became well known for their role in the development of the famous programming language
ALGOL
ALGOL (; short for "Algorithmic Language") is a family of imperative computer programming languages originally developed in 1958. ALGOL heavily influenced many other languages and was the standard method for algorithm description used by the ...
. After the first European ALGOL conference in 1959, RC began an effort to produce a series of compilers, completing one for the DASK in September 1961. A version for the GIER followed in August 1962. Christian Andersen and Peter Schyum Poulsen, another RC employee, wrote the first introductory text on the language, ''Everyman's Desk ALGOL'', in 1961.
Peripheral business
To support higher throughput at their own service bureau, RC developed several high-speed
input/output
In computing, input/output (I/O, i/o, or informally io or IO) is the communication between an information processing system, such as a computer, and the outside world, such as another computer system, peripherals, or a human operator. Inputs a ...
devices. One of their most popular was the
RC 2000 paper tape reader, introduced in 1963. Feeding the tape at 5 meters per second, the 2000 could read 2,000 characters per second (CPS), storing the results in a buffer while the computer periodically read the data back out instead of stopping the tape to wait for the computer to get ready. The machine was later upgraded as the RC 2500, increasing speed to almost 7 meters a second, improving read speed to 2500 CPS. The RC 2000/2500 became a major product for RC during the 1960s, selling 1,500 examples around the world. Several related devices were added to the line, including a high-speed punch and a dedicated data conversion machine that would "massage" data between formats to ease the burden on the host computer.
In 1964 Regnecentralen was taken public. Most of the firm's shares were held by its biggest customers.
New computers
In the mid-1960s, RC began the design of a small
integrated circuit
An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...
-based computer system for industrial control and
automation
Automation describes a wide range of technologies that reduce human intervention in processes, mainly by predetermining decision criteria, subprocess relationships, and related actions, as well as embodying those predeterminations in machine ...
needs, initially to fill a request by a Danish company to automate a chemical factory they were building in
Poland
Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...
. The
RC 4000 design emerged in 1966 and was completed for the factory the next year. When combined with appropriate
peripheral
A peripheral device, or simply peripheral, is an auxiliary hardware device that a computer uses to transfer information externally. A peripheral is a hardware component that is accessible to and controlled by a computer but is not a core compo ...
s, almost always including an RC 2000 along with several rebranded devices from other companies, the RC 4000 was a highly reliable
minicomputer
A minicomputer, or colloquially mini, is a type of general-purpose computer mostly developed from the mid-1960s, built significantly smaller and sold at a much lower price than mainframe computers . By 21st century-standards however, a mini is ...
, and went on to be sold across Europe. The
RC 8000 from the mid-1970s used newer-generation
integrated circuit
An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...
s (ICs) to shrink the RC 4000 into a single
rack-mount system. The last in the series, the
RC 9000, further shrunk the machine and improved performance to about 4
MIPS, and was sold in versions that could run either RC 8000 programs, or
Unix
Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...
.
The RC 4000 is famous for its
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 ...
, developed by
Per Brinch Hansen
Per Brinch Hansen (13 November 1938 – 31 July 2007) was a Denmark, Danish-United States, American computer scientist known for his work in operating systems, Concurrent computing, concurrent Computer programming, programming and Parallel comput ...
. Known as the
RC 4000 multiprogramming system, it is the first real-world example of a system using a very simple kernel along with a variety of user-selected programs that built up the system as a whole. Today this concept is known as a
microkernel
In computer science, a microkernel (often abbreviated as μ-kernel) is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, ...
, and efforts to correct for microkernels' poor performance formed the basis of most OS research through the 1970s and 1980s. Brinch Hansen also worked with
Charles Simonyi
Charles Simonyi (; , ; born September 10, 1948) is a Hungarian Americans, Hungarian-American software architect.
He introduced the graphical user interface to Bill Gates for the first time who later described it as the first of two revolutiona ...
and
Peter Kraft on the RC 4000's
Real-time Control System
Real-time Control System (RCS) is a reference model enterprise architecture, architecture, suitable for many software-intensive, real-time computing control problem domains. It defines the types of functions needed in a real-time intelligent contr ...
.

RC also began selling the
Data General Nova under license in 1970 as the
RC 7000, later introducing their own updated version as the
RC 3600 the next year. This series filled a niche similar to the RC 4000, but for much smaller installations. The RC 3600 became a fixture of many Danish schools and universities.
During the 1980s, RC produced th
RC700 Piccolo th
RC750 Partner and th
RC759 Piccolinesystems, which were sold to Danish schools mostly, and to some businesses in Denmark and abroad. The Piccolo was powered by the
Zilog
Zilog, Inc. is an American manufacturer of microprocessors, microcontrollers, and application-specific embedded System on a chip, system-on-chip (SoC) products.
The company was founded in 1974 by Federico Faggin and Ralph Ungermann, who were soo ...
Z80A CPU, while the Piccoline was powered by the
Intel
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...
80186 processor.
In 1988,
International Computers Limited
International Computers Limited (ICL) was a British computer hardware, computer software and computer services company that operated from 1968 until 2002. It was formed through a merger of International Computers and Tabulators (ICT), English Ele ...
(ICL) acquired a 50% stake in Regnecentralen, then trading as RC Computer, with the intention of merging the business into ICL Denmark.
However, the business persisted as a distinct operational entity under the RC International name.
References
External links
Regnecentralen:
Regnecentralen (RC)Google translation – museum site with many RC related papers, mostly in
Danish. Contains also computer simulators (there's one for GIER
English page
Highlights of RC's History– overview of RC's history, scanned from a booklet presumably created in the 1970s. Several important pages are missing.
Eulogy: Niels Ivar Bech, 1920-1975
{{Authority control
Computer companies of Denmark
Defunct computer hardware companies
Defunct computer systems companies
Home computer hardware companies
Computer companies established in 1955
International Computers Limited
1955 establishments in Denmark