Project origin and plan
ENIAC inventors John Mauchly and J. Presper Eckert proposed the EDVAC's construction in August 1944, and design work for the EDVAC commenced before the ENIAC was fully operational. The design would implement a number of important architectural and logical improvements conceived during the ENIAC's construction and would incorporate a high speed serial access memory. Like the ENIAC, the EDVAC was built for the U.S. Army's Ballistics Research Laboratory at the Aberdeen Proving Ground by the University of Pennsylvania's Moore School of Electrical Engineering. Eckert and Mauchly and the other ENIAC designers were joined by John von Neumann in a consulting role; von Neumann summarized and discussed logical design developments in the 1945 First Draft of a Report on the EDVAC. A contract to build the new computer was signed in April 1946 with an initial budget of US$100,000. The contract named the device the Electronic Discrete Variable Automatic Calculator. The final cost of EDVAC, however, was similar to the ENIAC's, at just under $500,000. Technical description
The EDVAC was a binary serial computer with automatic addition, subtraction, multiplication, programmed division and automatic checking with an ultrasonic serial memory capacity of 1,000 44-bit words (later set to 1,024 words, thus giving a memory, in modern terms, of 5.5 kilobytes). Installation and operation
EDVAC was delivered to the Ballistics Research Laboratory in August 1949. After a number of problems had been discovered and solved, the computer began operation in 1951 although only on a limited basis. Its completion was delayed because of a dispute over patent rights between Eckert and Mauchly and the University of Pennsylvania, resulting in Eckert and Mauchly's resignation and departure to form the Eckert–Mauchly Computer Corporation and taking most of the senior engineers with them. By 1960 EDVAC was running over 20 hours a day with error-free run time averaging eight hours. EDVAC received a number of upgrades including punch-card I/O in 1953, extra memory in slower magnetic drum form in 1954, and a floating point arithmetic unit in 1958. EDVAC ran until 1961 when it was replaced by BRLESC. During its operational life it proved to be reliable and productive for its time. Plankalkül (German pronunciation: [ˈplaːnkalkyːl], "Plan Calculus") is a computer language designed for engineering purposes by Konrad Zuse between 1943 and 1945. It was the first high-level non-von Neumann programming language to be designed for a computer. Also, notes survive with scribblings about such a plan calculation dating back to 1941. Plankalkül was not published at that time owing to a combination of factors such as conditions in wartime and postwar Germany and his efforts to commercialise the Z3 computer and its successors. By 1946, Zuse had written a book on the subject but this remained unpublished. In 1948 Zuse published a paper about the Plankalkül in the "Archiv der Mathematik" but still did not attract much feedback - for a long time to come programming a computer would only be thought of as programming with machine code. The Plankalkül was eventually more comprehensively published in 1972 and the first compiler for it was implemented in 1998. Another independent implementation followed in the year 2000 by the Free University of Berlin. "Kalkül" means formal system – the Hilbert-style deduction system is for example originally called "Hilbert-Kalkül", so Plankalkül means "formal system for planning". A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a...