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Bell Laboratories scientist George Stibitz uses relays for a demonstration adder
Called the “Model K” Adder because he built it on his “Kitchen” table, this simple demonstration circuit provides proof of concept for applying Boolean logic to the design of computers, resulting in construction of the relay-based Model I Complex Calculator in 1939. That same year in Germany, engineer Konrad Zuse built his Z2 computer, also using telephone company relays. -
Hewlett-Packard is founded
David Packard and Bill Hewlett found their company in a Palo Alto, California garage. Their first product, the HP 200A Audio Oscillator, rapidly became a popular piece of test equipment for engineers. Walt Disney Pictures ordered eight of the 200B model to test recording equipment and speaker systems for the 12 specially equipped theatres that showed the movie “Fantasia” in 1940. -
The Complex Number Calculator (CNC) is completed
In 1939, Bell Telephone Laboratories completes this calculator, designed by scientist George Stibitz. In 1940, Stibitz demonstrated the CNC at an American Mathematical Society conference held at Dartmouth College. Stibitz stunned the group by performing calculations remotely on the CNC (located in New York City) using a Teletype terminal connected via to New York over special telephone lines. This is likely the first example of remote access computing. -
Konrad Zuse finishes the Z3 Computer
The Z3, an early computer built by German engineer Konrad Zuse working in complete isolation from developments elsewhere, uses 2,300 relays, performs floating point binary arithmetic, and has a 22-bit word length. The Z3 was used for aerodynamic calculations but was destroyed in a bombing raid on Berlin in late 1943. Zuse later supervised a reconstruction of the Z3 in the 1960s, which is currently on display at the Deutsches Museum in Munich. -
The first Bombe is completed
Built as an electromechanical mechanical means of decrypting Nazi ENIGMA-based military communications during World War II, the British Bombe is conceived of by computer pioneer Alan Turing and Harold Keen of the British Tabulating Machine Company. Hundreds of bombes were built, their purpose to ascertain the daily rotor start positions of Enigma cipher machines, which in turn allowed the Allies to decrypt German messages. -
The Atanasoff-Berry Computer (ABC) is completed
After successfully demonstrating a proof-of-concept prototype in 1939, Professor John Vincent Atanasoff receives funds to build a full-scale machine at Iowa State College (now University). The machine was designed and built by Atanasoff and graduate student Clifford Berry between 1939 and 1942. The ABC was at the center of a patent dispute related to the invention of the computer, which was resolved in 1973 when it was shown that ENIAC co-designer John Mauchly had seen the ABC shortly after it b -
Bell Labs Relay Interpolator is completed
The US Army asked Bell Laboratories to design a machine to assist in testing its M-9 gun director, a type of analog computer that aims large guns to their targets. Mathematician George Stibitz recommends 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, was used for other applications following the war. -
Curt Herzstark designs Curta calculator
Curt Herzstark was an Austrian engineer who worked in his family’s manufacturing business until he was arrested by the Nazis in 1943. While imprisoned at Buchenwald concentration camp for the rest of World War II, he refines his pre-war design of a calculator featuring a modified version of Leibniz’s “stepped drum” design. After the war, Herzstark’s Curta made history as the smallest all-mechanical, four-function calculator ever built. -
Project Whirlwind begins
During World War II, the US Navy approached the Massachusetts Institute of Technology (MIT) about building a flight simulator to train bomber crews. The team first builds a large analog computer, but found it inaccurate and inflexible. After designers saw a demonstration of the ENIAC computer, they decided instead on using a digital approach, while the project slowly changed from a flight simulator to an air defense system. By the time Whirlwind was completed in 1951, the Navy had lost interest -
First Colossus operational at Bletchley Park
Designed by British engineer Tommy Flowers, the Colossus is designed to break the complex Lorenz ciphers used by the Nazis during World War II. A total of ten Colossi were delivered, each using as many as 2,500 vacuum tubes. 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. Most historians believe that the use of Colossus machines significantly shortene -
Harvard Mark 1 is completed
Conceived by Harvard physics professor Howard Aiken, and designed and built by IBM, the Harvard Mark 1 is a room-sized, relay-based calculator. The machine had a fifty-foot long camshaft running the length of machine that synchronized the machine’s thousands of component parts and used 3,500 relays. The Mark 1 produced mathematical tables but was soon superseded by electronic stored-program computers. -
John von Neumann writes First Draft of a Report on the EDVAC
In a widely circulated paper, mathematician John von Neumann outlines the architecture of a stored-program computer, including electronic storage of programming information and data -- which eliminates the need for more clumsy methods of programming such as plugboards, punched cards and paper. Hungarian-born von Neumann demonstrated prodigious expertise in hydrodynamics, ballistics, meteorology, game theory, statistics, and the use of mechanical devices for computation. After the war, he concent -
Moore School lectures take place
An inspiring summer school on computing at the University of Pennsylvania´s Moore School of Electrical Engineering stimulates construction of stored-program computers at universities and research institutions in the US, France, the UK, and Germany. Among the lecturers were early computer designers like John von Neumann, Howard Aiken, J. Presper Eckert and John Mauchly, as well as mathematicians including Derrick Lehmer, George Stibitz, and Douglas Hartree. Students included future computing pion -
Public unveiling of ENIAC
Started in 1943, the ENIAC computing system was built by John Mauchly and J. Presper Eckert at the Moore School of Electrical Engineering of the University of Pennsylvania. Because of its electronic, as opposed to electromechanical, technology, it is over 1,000 times faster than any previous computer. ENIAC used plugboards and switches for programming, occupied more than 1,000 square feet, used about 18,000 vacuum tubes and weighed 30 tons. It was believed that ENIAC had done more calculation ov -
First Computer Program to Run on a Computer
University of Manchester researchers Frederic Williams, Tom Kilburn, and Geoff Toothill develop the Small-Scale Experimental Machine (SSEM), better known as the Manchester Baby. The Baby was built to test a new memory technology developed by Williams and Kilburn -- soon known as the Williams Tube – which was the first electronic random access memory for a computer. The first program, consisting of seventeen instructions and written by Kilburn, ran on June 21st, 1948. This was the first program t -
SSEC goes on display
The Selective Sequence Electronic Calculator (SSEC) project, led by IBM engineer Wallace Eckert, uses both relays and vacuum tubes to process scientific data at the rate of 50 multiplication per second. Before it’s decommissioning in 1952, the SSEC produced the moon-position tables used for plotting the course of the 1969 Apollo flight to the moon. The SSEC was one of the few and last of the generation of ‘super calculators’ to be built using electromechanical technology -
CSIRAC runs first program
While many early digital computers were based on similar designs, such as the IAS and its copies, others are unique designs, like the CSIRAC. Built in Sydney, Australia by the Council of Scientific and Industrial Research for use in its Radio physics Laboratory in Sydney, CSIRAC was designed by British-born Trevor Pearcey, and used unusual 12-hole paper tape. It was transferred to the Department of Physics at the University of Melbourne in 1955 and remained in service until 1964. -
EDSAC completed
The first practical stored-program computer, EDSAC is built at Cambridge University using vacuum tubes and mercury delay lines for memory. The EDSAC project was led by Cambridge professor and director of the Cambridge Computation Laboratory, Maurice Wilkes. Wilkes' ideas grew out of the Moore School lectures he had attended three years earlier. One major advance in programming was Wilkes' use of a library of short programs, called “subroutines,” stored on punched paper tapes and used for perform -
MADDIDA developed
MADDIDA is a digital drum-based differential analyzer. This type of computer is useful in performing many of the mathematical equations scientists and engineers encounter in their work. It was originally created for a nuclear missile design project in 1949 by a team led by Fred Steele. It used 53 vacuum tubes and hundreds of germanium diodes, with a magnetic drum for memory. Tracks on the drum did the mathematical integration. MADDIDA was flown across the country for a demonstration to John von -
Manchester Mark I completed
Built by a team led by engineers Frederick Williams and Tom Kilburn, the Mark I serves as the prototype for Ferranti’s first computer – the Ferranti Mark 1. The Manchester Mark I used more than 1,300 vacuum tubes and occupied an area the size of a medium room. Its “Williams-Kilburn tube” memory system was later adopted by several other early computer systems around the world. -
ERA 1101 introduced
One of the first commercially produced computers, the company´s first customer was the US Navy. The 1101, designed by ERA but built by Remington-Rand, was intended for high-speed computing and stored 1 million bits on its magnetic drum, one of the earliest magnetic storage devices and a technology which ERA had done much to perfect in its own laboratories. Many of the 1101’s basic architectural details were used again in later Remington-Rand computers until the 1960s. -
NPL Pilot ACE completed
Based on ideas from Alan Turing, Britain´s Pilot ACE computer is constructed 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, Massachusetts. The design packed 800 vacuum tubes into a relatively compact 12 square feet. -
First Univac 1 delivered to US Census Bureau
The Univac 1 is the first commercial computer to attract widespread public attention. Although manufactured by Remington Rand, the machine was often mistakenly referred to as “the IBM Univac." Univac computers were used in many different applications but utilities, insurance companies and the US military were major customers. One biblical scholar even used a Univac 1 to compile a concordance to the King James version of the Bible. Created by Presper Eckert and John Mauchly -- designers of the ea -
Ferranti Mark I sold
The title of “first commercially available general-purpose computer” probably goes to Britain’s Ferranti Mark I for its sale of its first Mark I computer to Manchester University. The Mark 1 was a refinement of the experimental Manchester “Baby” and Manchester Mark 1 computers, also at Manchester University. A British government contract spurred its initial development but a change in government led to loss of funding and the second and only other Mark I was sold at a major loss to the Universit -
Grimsdale and Webb build early transistorized computer
Working under Tom Kilburn at England’s Manchester University, Richard Grimsdale and Douglas Webb demonstrate a prototype transistorized computer, the "Manchester TC", on November 16, 1953. The 48-bit machine used 92 point-contact transistors and 550 diodes. -
IBM 650 magnetic drum calculator introduced
IBM establishes the 650 as its first mass-produced computer, with the company selling 450 in just one year. Spinning at 12,500 rpm, the 650´s magnetic data-storage drum allowed much faster access to stored information than other drum-based machines. The Model 650 was also highly popular in universities, where a generation of students first learned programming. -
The RAND Corporation’s JOHNNIAC runs
The JOHNNIAC computer is one of 17 computers that followed the basic design of Princeton's INstitute of Advanced Study (IAS) computer. It was named after John von Neumann, a world famous mathematician and computer pioneer of the day. Completed in 1954, JOHNNIAC was used for scientific and engineering calculations. It was also repeatedly expanded and improved throughout its 13-year lifespan. Many innovative programs were created for JOHNNIAC, including the time-sharing system JOSS that allowed ma -
English Electric DEUCE introduced
A commercial version of Alan Turing's Pilot ACE, called DEUCE—the Digital Electronic Universal Computing Engine -- is used mostly for science and engineering problems and a few commercial applications. Over 30 were completed, including one delivered to Australia. -
Librascope LGP-30 introduced
Physicist Stan Frankel, intrigued by small, general-purpose computers, developed the MINAC at Caltech. The Librascope division of defense contractor General Precision buys Frankel’s design, renaming it the LGP-30 in 1956. Used for science and engineering as well as simple data processing, the LGP-30 was a “bargain” at less than $50,000 and an early example of a ‘personal computer,’ that is, a computer made for a single user.
