__NOTOC__ The British Tabulating Machine Company (BTM) was a firm which manufactured and sold Hollerith

unit record equipment Starting at the end of the nineteenth century, well before the advent of electronic computers, data processing was performed using electromechanical machines collectively referred to as unit record equipment, electric accounting machines (EAM) or ...

and other data-processing equipment. During

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

, BTM constructed some 200 "

bombe The bombe () was an electro-mechanical device used by British cryptologists to help decipher German Enigma-machine-encrypted secret messages during World War II. The US Navy and US Army later produced their own machines to the same functi ...

s", machines used at

Bletchley Park Bletchley Park is an English country house and estate in Bletchley, Milton Keynes ( Buckinghamshire) that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years followin ...

to break the German Enigma machine ciphers. The company was formed in 1902 as The Tabulator Limited, after Robert Porter obtained the rights to sell

Herman Hollerith Herman Hollerith (February 29, 1860 – November 17, 1929) was a German-American statistician, inventor, and businessman who developed an electromechanical tabulating machine for punched cards to assist in summarizing information and, later, i ...

's patented machines from the US

Tabulating Machine Company The Computing-Tabulating-Recording Company (CTR) was a holding company of manufacturers of record-keeping and measuring systems subsequently known as IBM. In 1911, financier and noted trust organizer, "Father of Trusts", Charles R. Flint ama ...

(later to become IBM). By 1909, the company had been renamed the "British Tabulating Machine Company Limited". In 1920, the company moved from London to

Letchworth Letchworth Garden City, commonly known as Letchworth, is a town in the North Hertfordshire district of Hertfordshire, England. It is noted for being the first garden city. The population at the time of the 2011 census was 33,249. Letchworth ...

, Hertfordshire; it was also at this point that it started manufacturing its own machines, rather than simply reselling Hollerith equipment. Annual revenues were £6K in 1915, £122K in 1925, and £170K in 1937. In 1916 there were 45 staff; this increased to 132 in 1922, 326 in 1929 and 1,225 in 1939. In return for the exclusive right to market Hollerith equipment in Britain and the Empire (excluding Canada), BTM paid 25% of its revenues to the American company by way of royalties. This became an ever-increasing burden as the years progressed; BTM attempted to renegotiate the agreement on several occasions, but it was only finally terminated in 1948. During World War II, BTM was called upon to design and manufacture a machine to assist breaking the German Enigma machine

ciphers In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure. An alternative, less common term is ''encipherment''. To encipher or encode i ...

. This machine, known as a

, was initially conceived by

Alan Turing Alan Mathison Turing (; 23 June 1912 – 7 June 1954) was an English mathematician, computer scientist, logician, cryptanalyst, philosopher, and theoretical biologist. Turing was highly influential in the development of theoretical co ...

, but the actual machine was designed by BTM chief engineer Harold 'Doc' Keen, who had led the company's engineering department throughout the 1930s. The project was codenamed "CANTAB". The project was managed by computing pioneer Dora Metcalf until 1942. By the end of the European war, over two hundred bombes had been built and installed.

HEC computer

BTM built a valve based computer called the HEC (Hollerith Electronic Computer). The first model (HEC 1) was built in 1951, an example is held by the Birmingham Museum. BTM went on to develop the HEC 2, 2M and 4 models, eventually building more than 100. The machines had a 2 kilobyte drum memory and 1000 valves, and could use punched cards for input and output, or drive a printer.

Merger

In 1959 BTM merged with former rival

Powers-Samas Powers-Samas was a British company which sold unit record equipment. In 1915 Powers Tabulating Machine Company established European operations through the Accounting and Tabulating Machine Company of Great Britain Limited, in 1929 renamed Powe ...

to become International Computers and Tabulators Limited (ICT). ICT later became part of ICL ( International Computers Limited), which was later taken over by Fujitsu.

References

* John Harper, BTM – British Tabulating Machine Company Limite

* John Keen, Harold 'Doc' Keen and the Bletchley Park Bombe, 2003, . * Martin Campbell-Kelly, ICL and the British computer industry

*

External links

Letchworth's Enigma

Grace's Guide to British Industrial History – British Tabulating Machine Co

The BTM HEC Paperwork Collection at The ICL Computer Museum
{{Authority control Defunct manufacturing companies of the United Kingdom International Computers Limited Cryptanalytic devices Manufacturing companies established in 1902 1902 establishments in England British companies established in 1902 British companies disestablished in 1959 1959 disestablishments in England