A mechanical computer is built from mechanical components such as levers and gears, rather than electronic components. The most common examples are adding machines and mechanical counters, which use the turning of gears to increment output displays. More complex examples could carry out multiplication and division—Friden used a moving head which paused at each column—and even differential analysis. One model[ which? ] sold in the 1960s calculated square roots.
Mechanical computers can be either analog, using smooth mechanisms such as curved plates or slide rules for computations; or digital, which use gears.
Mechanical computers reached their zenith during World War II, when they formed the basis of complex bombsights including the Norden, as well as the similar devices for ship computations such as the US Torpedo Data Computer or British Admiralty Fire Control Table. Noteworthy are mechanical flight instruments for early spacecraft, which provided their computed output not in the form of digits, but through the displacements of indicator surfaces. From Yuri Gagarin's first manned spaceflight until 2002, every manned Soviet and Russian spacecraft Vostok, Voskhod and Soyuz was equipped with a Globus instrument showing the apparent movement of the Earth under the spacecraft through the displacement of a miniature terrestrial globe, plus latitude and longitude indicators.
Mechanical computers continued to be used into the 1960s, but were quickly replaced by electronic calculators, which—with cathode-ray tube output—emerged in the mid-1960s. The evolution culminated in the 1970s with the introduction of inexpensive handheld electronic calculators. Use of mechanical computers declined in the 1970s and was rare by the 1980s.
In 2016, NASA announced that its Automaton Rover for Extreme Environments program would use a mechanical computer to operate in the harsh environmental conditions found on Venus.
Early electrically powered computers constructed from switches and relay logic rather than vacuum tubes (thermionic valves) or transistors (from which later electronic computers were constructed) are classified as electro-mechanical computers. These varied greatly in design and capabilities, with some later units capable of floating point arithmetic. Some relay-based computers remained in service after the development of vacuum-tube computers, where their slower speed was compensated for by good reliability. Some models were built as duplicate processors to detect errors, or could detect errors and retry the instruction. A few models were sold commercially with multiple units produced, but many designs were experimental one-off productions.
|Automatic Relay Computer||UK||1948||The Booths, experimental|
|Harwell computer||UK||1951||later known as WITCH|
|Harvard Mark I||United States||1944||(IBM Automatic Sequence Controlled Calculator)|
|Harvard Mark II||USA||1947|
|Imperial College Computing Engine (ICCE)||UK||1951||Electro-mechanical|
|Office of Naval Research ONR Relay Computer||USA||1949||6-bit, drum storage, but electro-mechanical relay ALU based on Atlas, formerly Navy cryptology computer ABEL|
|OPREMA||East Germany||1955||Commercial use at Zeiss Optical in Jena|
|RVM-1||Soviet Union||1957||Alexander Kronrod|
|Simon||USA||1950||Hobbyist logic demonstrator magazine article|
|Bell Labs Model I||USA||1940||George Stibitz, "Complex Number Calculator",450 relays and cross bar switches, demonstrated remote access 1940, used until 1948|
|Bell Labs Model II||USA||1943||"Relay Interpolator", used for wartime work, shut down 1962|
|Bell Labs Model III||USA||1944||"Ballistic Computer", used until 1949|
|Bell Labs Model IV||USA||1945||Navy "Mark 22 Error Detector", used until 1961|
|Bell Labs Model V||USA||1946, 1947||Two units delivered, general purpose, built in trig functions, floating point|
|Bell Labs Model VI||USA||1949||General purpose, simplified Model V with several enhancements|
|Unnamed cryptanalysis multiplier||UK||1937||Turing|
|Relay Computer||USA||2006||Harry Porter's Relay Computer, demonstrator/hobby, but integrated circuit memory.|
The Analytical Engine was a proposed mechanical general-purpose computer designed by English mathematician and computer pioneer Charles Babbage. It was first described in 1837 as the successor to Babbage's difference engine, a design for a simpler mechanical computer.
An analog computer or analogue computer is a type of computer that uses the continuously changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities symbolically and by discrete values of both time and amplitude.
Computation is any type of calculation that includes both arithmetical and non-arithmetical steps and follows a well-defined model, for example an algorithm.
An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics.
The history of computing hardware covers the developments from early simple devices to aid calculation to modern day computers. Before the 20th century, most calculations were done by humans. Early mechanical tools to help humans with digital calculations, like the abacus, were called "calculating machines", called by proprietary names, or referred to as calculators. The machine operator was called the computer.
Digital electronics is a field of electronics involving the study of digital signals and the engineering of devices that use or produce them. This is in contrast to analog electronics and analog signals.
The Z3 was a German electromechanical computer designed by Konrad Zuse. It was the world's first working programmable, fully automatic digital computer. The Z3 was built with 2,600 relays, implementing a 22-bit word length that operated at a clock frequency of about 4–5 Hz. Program code was stored on punched film. Initial values were entered manually.
The history of computing is longer than the history of computing hardware and modern computing technology and includes the history of methods intended for pen and paper or for chalk and slate, with or without the aid of tables.
A mechanical calculator, or calculating machine, is a mechanical device used to perform the basic operations of arithmetic automatically. Most mechanical calculators were comparable in size to small desktop computers and have been rendered obsolete by the advent of the electronic calculator.
George Robert Stibitz was a Bell Labs researcher internationally recognized as one of the fathers of the modern first digital computer. He was known for his work in the 1930s and 1940s on the realization of Boolean logic digital circuits using electromechanical relays as the switching element.
The American Computer & Robotics Museum, formerly known as the American Computer Museum, is a museum of the history of computing, communications, artificial intelligence and robotics that is located in Bozeman, Montana, United States. It was founded in May 1990 by Barbara and George Keremedjiev as a non-profit organization. The museum was originally intended to have been located in Princeton, New Jersey, but the location was changed when the founders moved to Bozeman. It is likely the oldest extant museum dedicated to the history of computers in the world. The Computer Museum in Boston opened first, but it closed in 1999.
The history of computer science began long before our modern discipline of computer science, usually appearing in forms like mathematics or physics. Developments in previous centuries alluded to the discipline that we now know as computer science. This progression, from mechanical inventions and mathematical theories towards modern computer concepts and machines, led to the development of a major academic field, massive technological advancement across the Western world, and the basis of a massive worldwide trade and culture.
The Digi-Comp I was a functioning, mechanical digital computer sold in kit form. It was originally manufactured from polystyrene parts by E.S.R., Inc. starting in 1963 and sold as an educational toy for US$4.99.
The Digi-Comp II was a toy computer invented by John Thomas Godfrey and manufactured by E.S.R., Inc. that used 1⁄2 inch (12.5 mm) marbles rolling down a ramp to perform basic calculations. A two-level masonite platform with guides served as the medium for a supply of marbles that rolled down an inclined plane moving plastic cams as they went. The plastic cams played the part of flip-flops in an electronic computer - as a marble passed one of the cams, it would flip the cam around - in one position, the cam would allow the marble to pass in one direction, in the other position, it would cause the marble to drop through a hole and roll to the bottom of the ramp. The Digi-Comp II platform measures 14 by 28.5 inches.
Friden Calculating Machine Company was an American manufacturer of typewriters and mechanical, later electronic calculators. It was founded by Carl Friden in San Leandro, California, in 1934. Friden electromechanical calculators were robust and popular.
The Marchant Calculating Machine Co. was founded in 1911 by Rodney and Alfred Marchant in Oakland, California.
A quantum Turing machine (QTM) or universal quantum computer is an abstract machine used to model the effects of a quantum computer. It provides a simple model that captures all of the power of quantum computation—that is, any quantum algorithm can be expressed formally as a particular quantum Turing machine. However, the computationally equivalent quantum circuit is a more common model.
A computer is a machine that can be instructed to carry out sequences of arithmetic or logical operations automatically via computer programming. Modern computers have the ability to follow generalized sets of operations, called programs. These programs enable computers to perform an extremely wide range of tasks. A "complete" computer including the hardware, the operating system, and peripheral equipment required and used for "full" operation can be referred to as a computer system. This term may as well be used for a group of computers that are connected and work together, in particular a computer network or computer cluster.
Analog device are usually a combination of both analog machine and analog media that can together measure, record, reproduce, or broadcast continuous information, for example, the almost infinite number of grades of transparency, voltage, resistance, rotation, or pressure. In theory, the continuous information has an infinite number of possible values with the only limitation on resolution being the accuracy of the analog device.
This page serves as a timeline to show when analog devices were first made with digital circuits and systems.