Computer is a programmable machine. This means it can execute a programmed list of instructions and respond to new instructions that it is given. Today, however, the term is most often used to refer to the desktop and laptop computers that most people use. When referring to a desktop model, the term "computer" technically only refers to the computer itself -- not the monitor, keyboard, and mouse. Still, it is acceptable to refer to everything together as the computer. If you want to be really technical, the box that holds the computer is called the "system unit."
The first Bombe is completed. Based partly on the design of the Polish “Bomba,” a mechanical means of decrypting Nazi military communications during WWII, the British Bombe design was greatly influenced by the work of computer pioneer Alan Turing and others. Many bombes were built. Together they dramatically improved the intelligence gathering and processing capabilities of Allied forces. [Computers]
The Relay Interpolator is completed. The U.S. Army asked Bell Labs to design a machine to assist in testing its M-9 Gun Director. Bell Labs mathematician George Stibitz recommended using a relay-based calculator for the project. The result was the Relay Interpolator, later called the Bell Labs Model II. The Relay Interpolator used 440 relays and since it was programmable by paper tape, it was used for other applications following the war.
The first Colossus is operational at Bletchley Park. Designed by British engineer Tommy Flowers, the Colossus was designed to break the complex Lorenz ciphers used by the Nazis during WWII. A total of ten Colossi were delivered to Bletchley, each using 1,500 vacuum tubes and a series of pulleys transported continuous rolls of punched paper tape containing possible solutions to a particular code. Colossus reduced the time to break Lorenz messages from weeks to hours. The machine’s existence was not made public until the 1970s.
On September 9th, Grace Hopper recorded the first actual computer "bug" — a moth stuck between the relays and logged at 15:45 hours on the Harvard Mark II. Hopper, a rear admiral in the U.S. Navy, enjoyed successful careers in academia, business, and the military while making history in the computer field. She helped program the Harvard Mark I and II and developed the first compiler, A-0. Her subsequent work on programming languages led to COBOL, a language specified to operate on machines of different manufacturers.
Konrad Zuse began work on Plankalkul (Plan Calculus), the first algorithmic programming language, with an aim of creating the theoretical preconditions for the formulation of problems of a general nature. Seven years earlier, Zuse had developed and built the world´s first binary digital computer, the Z1. He completed the first fully functional program-controlled electromechanical digital computer, the Z3, in 1941. Only the Z4 — the most sophisticated of his creations — survived World War II.
An inspiring summer school on computing at the University of Pennsylvania´s Moore School of Electrical Engineering stimulated construction of stored-program computers at universities and research institutions. This free, public set of lectures inspired the EDSAC, BINAC, and, later, IAS machine clones like the AVIDAC. Here, Warren Kelleher completes the wiring of the arithmetic unit components of the AVIDAC at Argonne National Laboratory. Robert Dennis installs the inter-unit wiring as James Woody Jr. adjusts the deflection control circuits of the memory unit.
On December 23, William Shockley, Walter Brattain, and John Bardeen successfully tested this point-contact transistor, setting off the semiconductor revolution. Improved models of the transistor, developed at AT&T Bell Laboratories, supplanted vacuum tubes used on computers at the time.
Norbert Wiener published "Cybernetics," a major influence on later research into artificial intelligence. He drew on his World War II experiments with anti-aircraft systems that anticipated the course of enemy planes by interpreting radar images. Wiener coined the term "cybernetics" from the Greek word for "steersman."
Claude Shannon´s "The Mathematical Theory of Communication" showed engineers how to code data so they could check for accuracy after transmission between computers. Shannon identified the bit as the fundamental unit of data and, coincidentally, the basic unit of computation.
The Manchester Mark I computer functioned as a complete system using the Williams tube for memory. This University machine became the prototype for Ferranti Corp.´s first computer.
The National Bureau of Standards constructed the SEAC (Standards Eastern Automatic Computer) in Washington as a laboratory for testing components and systems for setting computer standards. The SEAC was the first computer to use all-diode logic, a technology more reliable than vacuum tubes, and the first stored-program computer completed in the United States. Magnetic tape in the external storage units (shown on the right of this photo) stored programming information, coded subroutines, numerical data, and output.
The National Bureau of Standards completed its SWAC (Standards Western Automatic Computer) at the Institute for Numerical Analysis in Los Angeles. Rather than testing components like its companion, the SEAC, the SWAC had an objective of computing using already-developed technology.
Alan Turing´s philosophy directed design of Britain´s Pilot ACE at the National Physical Laboratory. "We are trying to build a machine to do all kinds of different things simply by programming rather than by the addition of extra apparatus," Turing said at a symposium on large-scale digital calculating machinery in 1947 in Cambridge, 
England´s first commercial computer, the Lyons Electronic Office, solved clerical problems. The president of Lyons Tea Co. had the computer, modeled after the EDSAC, built to solve the problem of daily scheduling production and delivery of cakes to the Lyons tea shops. After the success of the first LEO, Lyons went into business manufacturing computers to meet the growing need for data processing systems.
The UNIVAC I delivered to the U.S. Census Bureau was the first commercial computer to attract widespread public attention. Although manufactured by Remington Rand, the machine often was mistakenly referred to as the "IBM UNIVAC." Remington Rand eventually sold 46 machines at more than $1 million each.F.O.B. factory $750,000 plus $185,000 for a high speed printer.
On election night, November 4, CBS News borrowed a UNIVAC to make a scientific prediction of the outcome of the race for the presidency between Dwight D. Eisenhower and Adlai Stevenson. The opinion polls predicted a landslide in favor of Stevenson, but the UNIVAC´s analysis of early returns showed a clear victory for Eisenhower. Its sharp divergence from public opinion made newscasters Walter Cronkite and Charles Collingwood question the validity of the computer´s forecast, so they postponed announcing UNIVAC´s prediction until very late.
Grace Hopper completes the A-0 Compiler. In 1952, mathematician Grace Hopper completed what is considered to be the first compiler, a program that allows a computer user to use English-like words instead of numbers. Other compilers based on A-0 followed: ARITH-MATIC, MATH-MATIC and FLOW-MATIC [software]
Magnetic tape allows for inexpensive mass storage of information and so is a key part of the computer revolution. The IBM 726 was one of the first practical high-speed magnetic tape systems for electronic digital computers. Announced on May 21, 1952, the system used a unique ‘vacuum channel’ method of keeping a loop of tape circulating between two points allowing the tape drive to start and stop the tape in a split-second. The Model 726 was first sold with IBM’s first electronic digital computer the Model 701 and could store 2 million digits per tape—an enormous amount at the time. It rented for $850 a month.
IBM shipped its first electronic computer, the 701. During three years of production, IBM sold 19 machines to research laboratories, aircraft companies, and the federal government.
The IBM 650 magnetic drum calculator established itself as the first mass-produced computer, with the company selling 450 in one year. Spinning at 12,500 rpm, the 650´s magnetic data-storage drum allowed much faster access to stored material than drum memory machines.
Alan Turing was found dead at age 42. He had published his seminal paper, "On Computable Numbers," in 1936, as well as posing significant questions about judging "human intelligence" and programming and working on the design of several computers during the course of his career.
MIT researchers built the TX-0, the first general-purpose, programmable computer built with transistors. For easy replacement, designers placed each transistor circuit inside a "bottle," similar to a vacuum tube. Constructed at MIT´s Lincoln Laboratory, the TX-0 moved to the MIT Research Laboratory of Electronics, where it hosted some early imaginative tests of programming, including a Western movie shown on TV, 3-D tic-tac-toe, and a maze in which mouse found martinis and became increasingly inebriated.
At MIT, researchers began experimentation on direct keyboard input on computers, a precursor to today´s normal mode of operation. Doug Ross wrote a memo advocating direct access in February; five months later, the Whirlwind aided in such an experiment.
The era of magnetic disk storage dawned with IBM´s shipment of a 305 RAMAC to Zellerbach Paper in San Francisco. The IBM 350 disk file served as the storage component for the Random Access Method of Accounting and Control. It consisted of 50 magnetically coated metal platters with 5 million bytes of data. The platters, stacked one on top of the other, rotated with a common drive shaft.
In Minneapolis, the original Engineering Research Associates group led by Bill Norris left Sperry Rand to form a new company, Control Data Corp., which soon released its model 1604 computer.
Sperry Rand released a commercial compiler for its UNIVAC. Developed by Grace Hopper as a refinement of her earlier innovation, the A-0 compiler, the new version was called MATH-MATIC. Earlier work on the A-0 and A-2 compilers led to the development of the first English-language business data processing compiler, B-0 (FLOW-MATIC), also completed in 1957. FLOW-MATIC served as a model on which to build with input from other sources.
A new language, FORTRAN (short for FORmula TRANslator), enabled a computer to perform a repetitive task from a single set of instructions by using loops. The first commercial FORTRAN program ran at Westinghouse, producing a missing comma diagnostic. A successful attempt followed.
SAGE — Semi-Automatic Ground Environment — linked hundreds of radar stations in the United States and Canada in the first large-scale computer communications network. An operator directed actions by touching a light gun to the screen.
