The following is a chronological listing of significant events in the development of the field of Information Technology between 1940 and 1949. For other time periods see:
- Chronology of Events - Pre-1700
- Chronology of Events - 1700s
- Chronology of Events - 1800s
- Chronology of Events - 1900-1930s
- Chronology of Events - 1950s
- Chronology of Events - 1960s
- Chronology of Events - 1970s
- Chronology of Events - 1980s
- Chronology of Events - 1990s
- Chronology of Events - 2000s
- Chronology of Events - 2010s
1940 — CBS demonstrates a color television.
1940 — Wire magnetic recorders intended for commercial use are demonstrated. They are not marketed to the general public until after the war.
1940 — The first portable two-way radio (the Handie-Talkie) becomes available.
1941 — A telecommunications department is established in the Ministry of PTT in France.
1942 — Machines are built by NCR for the Navy Computing Machine Lab to decrypt German and Japanese codes.
January 1944 — The secret British Colossus computer, designed by Alan Turing, is built. It had limited programmability, but demonstrates that a device using thousands of vacuum tubes can be reasonably reliable and electronically reprogrammable. It was used for breaking German wartime codes, including the Enigma code.
1945 — The concept of using geosynchronous satellites for communications purposes is first suggested by the science fiction writer Arthur C. Clarke, then employed at Britain's Royal Aircraft Establishment, part of the Ministry of Defence.
May 1945 — The ENIAC (Electronic Numerical Integrator and Computer), designed by J. Presper Eckert and J. Mauchley, is completed at the University of Pennsylvania. It uses decimal arithmetic and is sometimes called the first general purpose electronic computer. It is used by the U.S. Army's Ballistics Research Laboratory to compute ballistics tables. The first ENIAC instructions are typed in manually by 100 Navy women. It weighs more than 30 tons and uses more than 17,000 vacuum tubes, 70,000 resistors, and 10,000 capacitors.
July 1945 — Vannevar Bush publishes As We May Think, in which he proposed Memex (a conceptual machine that could store vast amounts of information, in which users have the ability to create information trails, links to related texts and illustrations, and which can be stored and used for future reference).
July 1945 — Vannevar Bush sends the Science-The Endless Frontier Report to President.
June 1946 — The first telephone call is made from a telephone installed in an automobile.
September 1947 — Rear Admiral Grace Murray Hopper discovers a moth trapped between the relays of a Navy computer. She calls it a "bug" — a term traditionally used to refer to a problem with an electrical device. She also coined the term "debugging" to describe efforts to fix a computer problem. [Date often erroneously reported as 1945.]
September 15, 1947 The Association of Computing Machinery (ACM) is formed.
1948 — The Monte Carlo computational estimation method is developed by S. Ulam and John von Neumann.
1948 — Cable television service begins.
1948 — Norbert Wiener (MIT) publishes "Cybernetics or Control and Communication in the Animal and the Machine." It was the first book that applied theories of information and communication to both biological systems and machines.
1948 — Widespread commercial use of magnetic tape begins in the United States.
1948 — Columbia Records introduces a long-playing disc using a narrow microgroove and revolving at 33-1⁄3 rpm. This allows a recording of up to 20 minutes on a side. It is called an LP (long-play) or album.
July, October 1948 — Claude E. Shannon publishes "A Mathematical Theory of Communication", one of the foundational works of the field of information theory. The article established a framework for determining the minimal data requirements to transmit information over noisy (imperfect) channels. It was later published in book format as "The Mathematical Theory of Communication."
1949 — George Orwell publishes the dystopian novel, Nineteen Eighty-Four.
1949 — RCA Victor introduces a long-playing 7-inch disc that plays at 45 rpm.
1949 — Electronic Controls Company, the first computer company, is founded by J. Presper Eckert and John Mauchly. The company is later renamed "EMCC" ("Eckert-Mauchly Computer Corporation") and releases a series of mainframe computers under the "UNIVAC" name.
Jan. 14, 1949 — The U.S. Department of Justice files an antitrust suit against AT&T, asking for separation of Western Electric from the Bell System. The case was resolved by a consent decree on January 1956.
May 6, 1949 — The Electronic Delay Storage Automatic Calculator (EDSAC), a British computer, performs its first calculations. It is the first practical stored-program electronic computer and the first to run a graphical computer game.