Elliott Brothers (computer company)
Elliott Brothers (London) Ltd 
Elliott Brothers (London) Ltd was an early computer company of the 1950s–60s in the United Kingdom, tracing its descent from a firm of instrument makers founded by William Elliott in London around 1804. The research laboratories were based at Borehamwood, originally set up in 1946. The first Elliott 152 computer appeared in 1950. Elliott's was a pioneer of Head-up displays - HUDs.
The well-known computer scientist Sir Tony Hoare was an employee there from August 1960 for eight years and wrote an ALGOL 60 compiler for the Elliott 803. He also worked on an operating system Elliott 503 Mark II for the computer, although this was less successful and abandoned along with "over thirty man-years of programming effort." (c.f. The Emperor's Old Clothes)
John Lansdown pioneered the use of computers as an aid to planning; making perspective drawings on an Elliott 803 computer in 1963, modelling a building's lifts and services, plotting the annual fall of daylight across its site, as well as authoring his own computer aided design (CAD) applications.
In 1966 the company established an integrated circuit design and manufacturing facility in Glenrothes, Scotland, followed by a MOS semiconductor research laboratory. The Glenrothes site was closed in 1969 following the take over of English Electric by GEC.
Elliott Automation 
Elliott Automation (as it had become) merged with English Electric in 1967. The data processing computer part of the company was then taken over by International Computers and Tabulators (ICT) in 1968; this marriage was forced by the British Government, who believed that the UK required a strong national computer company. The combined company was called International Computers Limited (ICL). The real-time computer part of Elliott Automation remained, and was renamed Marconi Elliott Computer Systems Limited in 1969 and GEC Computers Limited in 1972, and remained in the original Borehamwood research laboratories until the late 1990s. The agreement which governed the split of computer technologies between the two companies disallowed ICT from developing real-time computer systems and disallowed Elliott Automation from developing data processing computer systems for a few years after the split. The remainder of Elliott Automation which produced aircraft instruments and control systems, was retained by English Electric.
EASAMS was E A Space and Advanced Military Systems (the EA was never spelled out), based in Frimley, Surrey - first at the nearby Marconi Electronic Systems plant in Chobham Road and later, when it became a limited company, at its headquarters in Lyon Way. It evolved its proprietary EMPRENT an early PERT planning system used for the construction of North Sea Oil platform, and for the BAC TSR-2 which later was incorporated into MRCA multi-role combat aircraft which finally became Panavia Tornado. EASAMS senior management was highly conservative, and a number of innovative engineers working on 'private venture' projects such as Hierarchical Object Oriented Design HOOD and Ada language development left to form their own companies, including Admiral Computing which later merged with Logica, Systems Designers Ltd and Software Sciences (later part of IBM UK).
EASAMS Ltd was an independent company within GEC, founded in 1962 to provide services in system design, operational research and project management. In the 1990s EASAMS became part of Marconi Electronic Systems before losing its identity.
The following Elliott computer models were produced:
- Elliott 152 (1950)
- Elliott Nicholas (1952)
- Elliott/NRDC 401 (1953)
- Elliott 153 (DF computer) (1954)
- Elliott/GCHQ OEDIPUS (311) (1954)
- Elliott 402 (1955)
- Elliott 403 (WREDAC) (1955)
- Elliott 405 (1956)
- Elliott 802 (1958--1961) 6 were sold
- Elliott 803 (1959) about 250 sold, mainly 803B
- 803A had 4 or 8K of 39 bit words of memory and all internal data was held in a single 102 bit long serial path.
- 803B had 4 or 8K of 39 bit words of memory. The single data path was split into several shorter (48 bit long) serial paths to reduce instruction execution time. A hardware floating point option was available.
- Elliott ARCH 1000 (1962)
- Elliott 503 (1963) software compatible with 803
- Elliott 900 series (1963)
- Elliott 920 (used by Marconi Elliott Avionic Systems, at Elstree, in the Radar Research Lab, in late 70's)
- Elliott 502 (1964)
- Elliott 4100 series (1966) A joint development with NCR Corporation. Elliott selling to the scientific market and NCR selling to the commercial market.