Manheim introduced the ten inch design movable double sided cursor while a student in Paris. Since the slide rule works by manipulating distances to perform calculations, it is probably the first analog computer ever to have widespread use. In fact, it was used in engineering, science, and math as late as Since the slide rule is an analog device it's accuracy and usefulness were dependent upon the accuracy limitations of of the technology used in it's manufacture.
Early slide rules had an accuracy of only three digits. This proved sufficient precision for most works, but was not suited to situations where greater accuracy was needed.
As with Di Vinci, a chance discovery in and again in of some of German astronomer and mathematician Wilhelm Schickard's letters to his friend Johannes Kepler showed that Schickard devised a mechanical calculator in Schickard's invention was described to Kepler as a mechanical means for calculating ephemerides. Only two prototypes now lost were ever built at the time, one of which was used by Kepler.
Schickard's machine has been reconstructed based upon his diagrams. Blaise Pascal , an year-old in , invented what has come to be known as the "Pascaline" his name was "numerical wheel calculator" to facilitate his father's work as a French tax collector based in Paris. The numerical wheel calculator, or Pascaline, consisted of a rectangular box employing eight movable cogwheels or dials exploiting base ten to perform addition of sums up to eight figures long.
Specifically, as the dial for the one's column completed one revolution moved ten notches , it moved the next wheel, representing the tens column, one place. A complete revolution of the tens dial increased the hundred's dial one notch, so on through the entire eight wheels.
To add with the Pascaline one moved the cogwheels to the first number followed by each of the other numbers to be added. The Pascaline, though clever in design, had two shortcomings: 1 The user had to configure the wheels manually, and 2 its straightforward computational abilities extended only to addition. The Pascaline could be used to subtract and multiply by successive addition though each operation required much more from the user. Gottfried Wilhem von Leibniz , a German mathematician and philosopher, studied Pascal's original notes and drawings to created a machine that improved upon the Pascaline.
Leibniz's machine could add, subtract, multiply and divide. Leibniz modified the machine to include a stepped-drum gear design, called the Leibniz Wheel.
The Leibniz wheel was a movable carriage connecting pin wheels like Pascal's via stepped cylinders containing ridge-like teeth of different lengths corresponding to the digits 1 through 9. Turning the crank that connected the cylinders engaged the smaller gears above the cylinders, and these in turn engaged the adding section. The adding section consisted of a cylinder on which gearing teeth were set at varying lengths, which functioned as combined series of simple flat gears.
Leibniz called his final creation, commissioned in , the Stepped Reckoner. The Reckoner, however, required some user manipulation for carry-overs and often gave the wrong answers.
A design error in the carrying mechanism caused the machine to fail to carry tens correctly when the multiplier was a two or three digit number. Both Charles, the third Earl Stanhope, English and Mathieus Hahn Germanic; started , finished did make their own successful multiplying calculator similar to Leibniz's. The calculators of the 16 th and 17 th century provided to a limited extent a proof of concept that mechanical methods embodied in machines could perform lengthy and involved numerical calculations.
These machines represent the basic insights used in constructing mechanical calculators until the middle of the 20 th century. Nevertheless, the invention and use of devices capable of lengthy computations still required the development of several key elements. First, the machines of the 17 th and 18 th centuries operated at best semi-automatically.
At each new stage of a calculation the user has to manually intervene. Second, every machine is a special purpose machine designed and constructed to perform a single task or a very small number of tasks. Third, each individual calculation required the user to configure the machine. There was no notion of a program, i. In certain cases, users wrote down partial results and later re-entered them when they were needed to finish a calculation. Finally, since these machines operated by mechanical means, they were limited in complexity and speed.
The history of calculating machines from Leibniz to ENIAC and ACE is largely one of the ideological and technological advances that culminate in the construction of general purpose programmable computers. The 18 th and 19 th Centuries The development of more sophisticated computing machines in the 19 th century was marked by more failure than success.
In part the failures were due to the sheer complexity of the task. In part they were due to funding problems caused by the inability to envision the full impact of such machines upon diverse human activities.
At the end of the 18 th century, in , J. Mueller, a Hessian army officer, conceived the idea of what Babbage later calls the Difference Engine. Specifically, Mueller envisioned a mechanical calculator for determining polynomial values using Newton's method of differences. The method works by using a constant derived from subtracting values for the polynomial which can then be used to uniquely specify other values for the polynomial for a fixed interval.
Such a machine, though seemingly as specialized as the Pascaline, can be used to calculate values for any function that one can approximate over suitable intervals by a polynomial. Mueller's fund raising efforts proved fruitless, and the project was forgotten. The next significant development in computing did not occur until the 's. Charles Xavier Thomas de Colmar , a French industrialist, constructed and mass-produced the first calculator. Like Mueller, de Colmar began developing his idea while in the army.
De Colmar's "Arithmometer" employed the same stepped cylinder approach as Leibniz's calculator. In addition to multiplication, the Arithmometer could also perform division with user assistance. In a young Charles Babbage , the son of a banker and a gifted mathematician, entered Cambridge. According to Babbage's account in his autobiography, Passages from the Life of a Philosopher , his attention was first drawn to computing machinery in when I was sitting in the rooms of the Analytical Society, at Cambridge, my head leaning forward on the table in a kind of dreamy mood, with a table of logarithms lying open before me.
Another member, coming into the room, and seeing me half asleep, called out, Well, Babbage, what are you dreaming about? Some doubt the veracity of Babbage's above account. Babbage definitely did not act on his ideas until in connection with checking tables for the Royal Astronomical Society. The astronomical data, values for logarithms and trigonometric functions, as well as various physical constants encoded in the tables were heavily and extensively employed for scientific experimentation and nautical navigation.
The standard government tables for navigation, for instance, were known to have in excess of a 1, errors. Corrections for the navigation tables encompassed seven volumes. Babbage knew that the sources for the errors were the humans who had produced the tables.
The tables had been produced manually, and in some cases measures dated back over two centuries. In such an exhaustive compendium compiled over such a long expanse of time human calculating errors compounded by copyist mistakes had infected the tables like a virus.
Since the calculations for the tables were to a large extent tedious and mechanical, Babbage realized that a machine that could produce the tables would eliminate calculating and transcription errors as well as being incapable of suffering from the tedium of the task.
Babbage's first important step, and the only one which he fully realized, was the conception and construction of a prototype for his Difference Engine.
The Difference Engine, if Babbage had completed it, would have evaluated polynomials using the method of differences. Babbage began work on the prototype machine in and successfully demonstrated the machine without the ability to print its answers for the Royal Astronomical Society in At his demonstration Babbage proposed building a version of the machine that could calculate the necessary values and print these scientific tables. Impressed, the Society awarded him a gold medal and supported Babbage's proposal to build a full scale difference engine with an accuracy of 20 decimal places.
In , with an initial and historic grant of 1, English pounds, Babbage set to work. In addition to providing Babbage with a grant to produce the full scale Difference Engine, Babbage's prototype also brought him into contact with Ada, Countess of Lovelace. Ada was the only legitimate daughter of the poet Lord Byron though she never lived with him. The teenaged Ada Byron encountered the prototype and Babbage when at a society function intended to show off new inventions.
Miss Byron, who had been tutored by a family friend the great logician Augustus De Morgan, showed considerable intelligence, mathematical, and logical ability. She immediately grasped the workings of the machine and it's potential. In fact, Babbage once commented that she understood it better than himself and explained its functioning far better than he could. She and Babbage maintained constant contact for the rest her life.
By Babbage had long ago about 7 years abandoned work on the Difference Engine with only half of its 25, parts completed and only a single fragment assembled. He had suffered endless struggles for funding, accusations of fraud, and controversies with his academic peers, while spending 34, pounds of his own and the British Government's money. In Babbage had begun touring the continent lecturing upon his new invention which the British government refused to fund , the Analytical Engine.
Babbage's design for the Analytical Engine represents the first design for a computer in the modern sense. It had a memory, a processor, and a program. In devising the Analytical Engine Babbage utilized Joseph-Marie Jacquard's technology if encoding data on punch cards. Jacquard used pasteboard punch cards to encode patterns that could then guide the behavior of looms. The Analytical Engine had two pasteboard memory stores. One store held the "operation cards" specifying what Babbage called the formula the program.
The other store held the "variable cards" which determined the variables upon which the formula would operate as well as any intermediate values. The two stores fed into the mill, which then carried out the computations. The countess of Lovelace played an extremely important role in the development of the Analytical Engine.
She translated a French publication of notes on Babbage's Lectures on the Analytical Engine into English, adding an addendum that was longer than the article, but so insightful that Babbage urged its publication in toto. Though Babbage may have written algorithms for the difference engine in earlier notes, the algorithm in Lovelace's article makes her the first person to publish an algorithm intended to be carried out by such a machine.
As a result, she is often regarded as one of the first computer programmers. The countess also developed the programming techniques of subroutines , loops , and jumps. In addition, she meticulously documented the design and logic of the engine, providing the only clear records now available. A few years before his death Babbage began to fabricate the mill of the Analytical Engine.
After Babbage's death the British Association for the Advancement of Science submitted a report recommending against construction of the Analytical Engine. In his son had completed the mill for the engine to a great enough extent that he used it to calculate to its 44th place. By the mill was fully completed. Though Babbage failed to produce a working difference engine, in Georg Scheutz , a Swedish printer, publicist, writer, Shakespeare translator, and engineer, read of Babbage's difference engine in an article in the Edinburgh Review written by Dionysuis Lardner.
Working with his son Edvard, Georg Scheutz began to build a smaller version of the difference engine. Edvard was still in high school, and the two made their first engine in their kitchen from wood using hand tools and a makeshift lathe. Various units were built and demonstrated successfully, including a scale-of-four counter and a stepping ring--the means proposed for storing each decimal digit. Bush's memorandum reviewing progress-to-date contains estimates that the machine would be able to multiply two six-decimal digit numbers in about 0.
Overbeck took over in late and spent the next year or so devising special-purpose tubes in an attempt to reduce the number of vacuum tubes needed. Work on the project came to an abrupt and premature end in early , when Overbeck was claimed for work on the atomic bomb project. This office directed the work of some 30, scientists and engineers, working on everything from radar, proximity fuses, and amphibious vehicles, to the atom bomb.
The shortened title "Diff. Analyzer," inferring the construction of a Bush-type machine, included in the proposal to the NRDC for the funding of ENIAC by Brainerd for Mauchly and Eckert has been attributed to sensitivity to potential opposition to the project by Bush's associates. Outside the field of computation, Bush was probably best known for his leadership of the "Manhattan Project.
Yet the Rapid Arithmetical Machine project had been forgotten. It was rediscovered during the extensive historical investigations undertaken in connection with the patent litigation between Univac and Honeywell over the validity of the ENIAC patent--litigation that lasted six years and involved testimony by over witnesses and 30, pieces of evidence, ranging from a single sheet of paper to a file cabinet-full.
Bush's project played only a very small role in the evidence and the testimony, perhaps because none of the MIT people directly involved in the project testified at the trial.
Indeed, the Rapid Arithmetical Machine project was not mentioned in the page volume entitled Findings of Fact, Conclusions of Law and Order for Judgment that was the sole official publication resulting from the litigation. Bush had a long history of interest in the problem of information searching, and in wrote an article describing "Memex," composed of a desk which provided instant access to microphotographed books, periodicals, and documents.
Nyce and Kahn, After the war Bush returned to his responsibilities at the Carnegie Institution. When he retired in he went home to Cambridge and took up duties as a member of the boards of several companies, including the MIT Corp.
When Bush died in , papers such as the New York Times carried lengthy accounts of his most impressive career see Reinhold, They detailed his many inventions, his illustrious academic career at MIT and the Carnegie Institute, and, perhaps most important, his vital wartime role as director of the National Defense Research and Development.
James Thomson, brother of Lord Kelvin, invented the mechanical wheel-and-disc integrator that became the foundation of analog computation Thomson []. The two brothers constructed a device for computing the integral of the product of two given functions, and Kelvin described although did not construct general-purpose analog machines for integrating linear differential equations of any order and for solving simultaneous linear equations.
Kelvin's most successful analog computer was his tide predicting machine, which remained in use at the port of Liverpool until the s. Mechanical analog devices based on the wheel-and-disc integrator were in use during World War I for gunnery calculations. Following the war, the design of the integrator was considerably improved by Hannibal Ford Ford [].
Stanley Fifer reports that the first semi-automatic mechanical analog computer was built in England by the Manchester firm of Metropolitan Vickers prior to Fifer [], p. In , Vannevar Bush, working at MIT, built the differential analyser, the first large-scale automatic general-purpose mechanical analog computer. Bush's design was based on the wheel and disc integrator. Soon copies of his machine were in use around the world including, at Cambridge and Manchester Universities in England, differential analysers built out of kit-set Meccano, the once popular engineering toy.
It required a skilled mechanic equipped with a lead hammer to set up Bush's mechanical differential analyser for each new job. Subsequently, Bush and his colleagues replaced the wheel-and-disc integrators and other mechanical components by electromechanical, and finally by electronic, devices.
Each box performs a fundamental process, for example addition, multiplication of a variable by a constant, and integration. In setting up the machine for a given task, boxes are connected together so that the desired set of fundamental processes is executed.
Since all the boxes work in parallel, an electronic differential analyser solves sets of equations very quickly. Against this has to be set the cost of massaging the problem to be solved into the form demanded by the analog machine, and of setting up the hardware to perform the desired computation.
A major drawback of analog computation is the higher cost, relative to digital machines, of an increase in precision. However, such machines are now a rarity. In , at Cambridge University, Turing invented the principle of the modern computer. He described an abstract digital computing machine consisting of a limitless memory and a scanner that moves back and forth through the memory, symbol by symbol, reading what it finds and writing further symbols Turing [].
The actions of the scanner are dictated by a program of instructions that is stored in the memory in the form of symbols. This is Turing's stored-program concept, and implicit in it is the possibility of the machine operating on and modifying its own program.
Turing's computing machine of is now known simply as the universal Turing machine. Cambridge mathematician Max Newman remarked that right from the start Turing was interested in the possibility of actually building a computing machine of the sort that he had described Newman in interview with Christopher Evans in Evans [? Here he became familiar with Thomas Flowers' work involving large-scale high-speed electronic switching described below. However, Turing could not turn to the project of building an electronic stored-program computing machine until the cessation of hostilities in Europe in During the wartime years Turing did give considerable thought to the question of machine intelligence.
Colleagues at Bletchley Park recall numerous off-duty discussions with him on the topic, and at one point Turing circulated a typewritten report now lost setting out some of his ideas. One of these colleagues, Donald Michie who later founded the Department of Machine Intelligence and Perception at the University of Edinburgh , remembers Turing talking often about the possibility of computing machines 1 learning from experience and 2 solving problems by means of searching through the space of possible solutions, guided by rule-of-thumb principles Michie in interview with Copeland, At Bletchley Park Turing illustrated his ideas on machine intelligence by reference to chess.
Michie recalls Turing experimenting with heuristics that later became common in chess programming in particular minimax and best-first. Further information about Turing and the computer, including his wartime work on codebreaking and his thinking about artificial intelligence and artificial life, can be found in Copeland With some exceptions — including Babbage's purely mechanical engines, and the finger-powered National Accounting Machine - early digital computing machines were electromechanical.
These operate relatively slowly, whereas the basic components of an electronic computer — originally vacuum tubes valves — have no moving parts save electrons and so operate extremely fast. To Zuse belongs the honour of having built the first working general-purpose program-controlled digital computer.
This machine, later called the Z3, was functioning in A program-controlled computer, as opposed to a stored-program computer, is set up for a new task by re-routing wires, by means of plugs etc.
Relays were too slow and unreliable a medium for large-scale general-purpose digital computation although Aiken made a valiant effort. It was the development of high-speed digital techniques using vacuum tubes that made the modern computer possible.
The earliest extensive use of vacuum tubes for digital data-processing appears to have been by the engineer Thomas Flowers, working in London at the British Post Office Research Station at Dollis Hill. Electronic equipment designed by Flowers in , for controlling the connections between telephone exchanges, went into operation in , and involved between three and four thousand vacuum tubes running continuously. In — Flowers worked on an experimental electronic digital data-processing system, involving a high-speed data store.
Flowers' aim, achieved after the war, was that electronic equipment should replace existing, less reliable, systems built from relays and used in telephone exchanges. Flowers did not investigate the idea of using electronic equipment for numerical calculation, but has remarked that at the outbreak of war with Germany in he was possibly the only person in Britain who realized that vacuum tubes could be used on a large scale for high-speed digital computation.
See Copeland for m more information on Flowers' work. The earliest comparable use of vacuum tubes in the U. During the period — Atanasoff developed techniques for using vacuum tubes to perform numerical calculations digitally. In , with the assistance of his student Clifford Berry, Atanasoff began building what is sometimes called the Atanasoff-Berry Computer, or ABC, a small-scale special-purpose electronic digital machine for the solution of systems of linear algebraic equations.
The machine contained approximately vacuum tubes. Although the electronic part of the machine functioned successfully, the computer as a whole never worked reliably, errors being introduced by the unsatisfactory binary card-reader.
Work was discontinued in when Atanasoff left Iowa State. The first fully functioning electronic digital computer was Colossus, used by the Bletchley Park cryptanalysts from February These were designed by Turing and Gordon Welchman building on earlier work by Polish cryptanalysts. During the second half of , messages encoded by means of a totally different method began to be intercepted.
Based on binary teleprinter code, Tunny was used in preference to Morse-based Enigma for the encryption of high-level signals, for example messages from Hitler and members of the German High Command. The first machine designed and built to Newman's specification, known as the Heath Robinson, was relay-based with electronic circuits for counting. The electronic counters were designed by C.
Wynn-Williams, who had been using thyratron tubes in counting circuits at the Cavendish Laboratory, Cambridge, since [Wynn-Williams ]. Installed in June , Heath Robinson was unreliable and slow, and its high-speed paper tapes were continually breaking, but it proved the worth of Newman's idea.
Working independently at the Post Office Research Station at Dollis Hill, Flowers quietly got on with constructing the world's first large-scale programmable electronic digital computer. Colossus I was delivered to Bletchley Park in January By the end of the war there were ten Colossi working round the clock at Bletchley Park. From a cryptanalytic viewpoint, a major difference between the prototype Colossus I and the later machines was the addition of the so-called Special Attachment, following a key discovery by cryptanalysts Donald Michie and Jack Good.
The wheel patterns were eventually changed daily by the Germans on each of the numerous links between the German Army High Command and Army Group commanders in the field. By there were as many 30 links in total. About ten of these were broken and read regularly. Colossus I contained approximately vacuum tubes and each of the subsequent machines approximately vacuum tubes. Like the smaller ABC, Colossus lacked two important features of modern computers.
First, it had no internally stored programs. To set it up for a new task, the operator had to alter the machine's physical wiring, using plugs and switches. Second, Colossus was not a general-purpose machine, being designed for a specific cryptanalytic task involving counting and Boolean operations.
Most of the Colossi were destroyed once hostilities ceased. Some of the electronic panels ended up at Newman's Computing Machine Laboratory in Manchester see below , all trace of their original use having been removed. The last Colossus is believed to have stopped running in Those who knew of Colossus were prohibited by the Official Secrets Act from sharing their knowledge.
Until the s, few had any idea that electronic computation had been used successfully during the second world war. In and , respectively, Good and Michie published notes giving the barest outlines of Colossus.
By , Flowers had received clearance from the British Government to publish a partial account of the hardware of Colossus I. Details of the later machines and of the Special Attachment, the uses to which the Colossi were put, and the cryptanalytic algorithms that they ran, have only recently been declassified.
For the full account of Colossus and the attack on Tunny see Copeland To those acquainted with the universal Turing machine of , and the associated stored-program concept, Flowers' racks of digital electronic equipment were proof of the feasibility of using large numbers of vacuum tubes to implement a high-speed general-purpose stored-program computer.
0コメント