Information about Harvard Mark Ii
The Harvard Mark II was an electromechanical computer built at Harvard University under the direction of Howard Aiken and was finished in 1947. It was financed by the United States Navy.
The Mark II was constructed with high-speed electromagnetic relays instead of electro-mechanical counters used in the Mark I, making it much faster than its predecessor. Its addition time was 125,000 microseconds and the multiplication time was 750,000 microseconds. (This was a factor of 2.6 and a factor 8 faster, respectively, compared to the Mark I.) It was the second machine (after the Bell Labs Relay Calculator) to have floating-point hardware. A unique feature of the Mark II is that it had built-in hardware for several functions such as the reciprocal, square root, logarithm, exponential, and some trigonometric functions. These took between five and twelve seconds to execute.
The Mark II was not a stored-program computer – it read an instruction of the program one at a time from a tape and executed it (like the Mark I). This separation of data and instructions is known as the Harvard architecture. The Mark II had a peculiar programming method that was devised to ensure that the contents of a register were available when needed. The tape containing the program could encode only eight instructions, so what a particular instruction code meant depended on when it was executed. Each second was divided up into several periods, and a coded instruction could mean different things in different periods. An addition could be started in any of eight periods in the second, a multiplication could be started in any of four periods of the second, and a transfer of data could be started in any of twelve periods of the second. Although this system worked, it made the programming complicated, and it reduced the efficiency of the machine somewhat.
The Mark II ran some realistic test programs in July 1947. It was delivered to the US Navy Proving Ground at Dahlgren, Virginia in 1947 or 1948.
Usage of the term "bug" to describe inexplicable defects has been a part of engineering jargon for many decades; it may have originally been used in hardware engineering to describe mechanical malfunctions. For instance, the term was used by Thomas Edison, and also to describe radar electronics problems during World War II.
The first "documented" computer bug was a moth found trapped between points at Relay # 70, Panel F, of the Mark II Aiken Relay Calculator while it was being tested at Harvard University, 9 September 1947. Grace Hopper affixed the moth to the computer log, with the entry: "First actual case of bug being found".[1] The operators put out the word that they had "debugged" the machine, thus introducing the term "debugging a computer."
The Mark II was constructed with high-speed electromagnetic relays instead of electro-mechanical counters used in the Mark I, making it much faster than its predecessor. Its addition time was 125,000 microseconds and the multiplication time was 750,000 microseconds. (This was a factor of 2.6 and a factor 8 faster, respectively, compared to the Mark I.) It was the second machine (after the Bell Labs Relay Calculator) to have floating-point hardware. A unique feature of the Mark II is that it had built-in hardware for several functions such as the reciprocal, square root, logarithm, exponential, and some trigonometric functions. These took between five and twelve seconds to execute.
The Mark II was not a stored-program computer – it read an instruction of the program one at a time from a tape and executed it (like the Mark I). This separation of data and instructions is known as the Harvard architecture. The Mark II had a peculiar programming method that was devised to ensure that the contents of a register were available when needed. The tape containing the program could encode only eight instructions, so what a particular instruction code meant depended on when it was executed. Each second was divided up into several periods, and a coded instruction could mean different things in different periods. An addition could be started in any of eight periods in the second, a multiplication could be started in any of four periods of the second, and a transfer of data could be started in any of twelve periods of the second. Although this system worked, it made the programming complicated, and it reduced the efficiency of the machine somewhat.
The Mark II ran some realistic test programs in July 1947. It was delivered to the US Navy Proving Ground at Dahlgren, Virginia in 1947 or 1948.
First computer bug
)
Photo of what is possibly the first actual bug found in a computer.
Usage of the term "bug" to describe inexplicable defects has been a part of engineering jargon for many decades; it may have originally been used in hardware engineering to describe mechanical malfunctions. For instance, the term was used by Thomas Edison, and also to describe radar electronics problems during World War II.
The first "documented" computer bug was a moth found trapped between points at Relay # 70, Panel F, of the Mark II Aiken Relay Calculator while it was being tested at Harvard University, 9 September 1947. Grace Hopper affixed the moth to the computer log, with the entry: "First actual case of bug being found".[1] The operators put out the word that they had "debugged" the machine, thus introducing the term "debugging a computer."
See also
Notes
References
- Michael R. Williams (1997). A History of Computing Technology. IEEE Computer Society Press. ISBN 0-8186-7739-2.
Harvard University (incorporated as The President and Fellows of Harvard College) is a private university in Cambridge, Massachusetts, USA and a member of the Ivy League.
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Howard Hathaway Aiken (March 8, 1900, Hoboken, New Jersey–March 14 1973, St. Louis, Missouri) was a pioneer in computing, being the primary engineer behind IBM's Harvard Mark I computer.
He studied at the University of Wisconsin-Madison, and later obtained his Ph.D.
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He studied at the University of Wisconsin-Madison, and later obtained his Ph.D.
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United States Navy (USN) is the branch of the United States armed forces responsible for conducting naval operations. The U.S. Navy currently has over 340,000 personnel on active duty and nearly 128,000 in the Navy Reserve.
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second (SI symbol: s), sometimes abbreviated sec., is the name of a unit of time, and is the International System of Units (SI) base unit of time.
SI prefixes are frequently combined with the word second to denote subdivisions of the second, e.g.
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SI prefixes are frequently combined with the word second to denote subdivisions of the second, e.g.
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von Neumann architecture is a computer design model that uses a processing unit and a single separate storage structure to hold both instructions and data. It is named after mathematician and early computer scientist John von Neumann.
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instruction set is (a list of) all instructions, and all their variations, that a processor can execute.
Instructions include:
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Instructions include:
- arithmetic such as add and subtract
- logic instructions such as and, or, and not
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Harvard architecture is a computer architecture with physically separate storage and signal pathways for instructions and data. The term originated from the Harvard Mark I relay-based computer, which stored instructions on punched tape (24 bits wide) and data in electro-mechanical
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Dahlgren, Virginia
Seal
Motto:
Location of Dahlgren, Virginia
Coordinates:
Country United States
State Virginia
County King George
Area
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Seal
Motto:
Location of Dahlgren, Virginia
Coordinates:
Country United States
State Virginia
County King George
Area
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Thomas Alva Edison (February 11 1847 – October 18 1931) was an American inventor and businessman who developed many devices that greatly influenced life around the world, including the phonograph and a long lasting light bulb.
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Radar is a system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain.
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Allied powers:
Soviet Union
United States
United Kingdom
China
France
...et al. Axis powers:
Germany
Japan
Italy
...et al.
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Soviet Union
United States
United Kingdom
China
France
...et al. Axis powers:
Germany
Japan
Italy
...et al.
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A software bug (or just "bug") is an error, flaw, mistake, failure, or fault in a computer program that prevents it from behaving as intended (e.g., producing an incorrect result).
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Grace Murray Hopper (December 9 1906 – January 1 1992) was an American computer scientist and United States Navy officer. A pioneer in the field, she was one of the first programmers of the Harvard Mark I calculator, and she developed the first compiler for a computer
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IBM Automatic Sequence Controlled Calculator (ASCC), called the Mark I by Harvard University[1], was the first large-scale automatic digital computer in the USA. It is considered by some to be the first universal calculator.
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The Harvard Mark III, also known as ADEC (for Aiken Dahlgren Electronic Calculator) was an early computer that was partially electronic and partially electromechanical.
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The Harvard Mark IV was an electronic stored-program computer built by Harvard University under the supervision of Howard Aiken for the United States Air Force. The computer was finished being built in 1952. It stayed at Harvard, where the Air Force used it extensively.
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Howard Hathaway Aiken (March 8, 1900, Hoboken, New Jersey–March 14 1973, St. Louis, Missouri) was a pioneer in computing, being the primary engineer behind IBM's Harvard Mark I computer.
He studied at the University of Wisconsin-Madison, and later obtained his Ph.D.
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He studied at the University of Wisconsin-Madison, and later obtained his Ph.D.
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The National Museum of American History is a museum administered by the Smithsonian Institution and located in Washington, D.C., on the National Mall. It opened in 1964 as the Museum of History and Technology and adopted its current name in 1980.
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