Computer is Multiple Device
A computer is a general-purpose device that can be programmed to carry out a set of arithmetic
or logical operations automatically. Since a sequence of operations can
be readily changed, the computer can solve more than one kind of
problem.Conventionally, a computer consists of at least one processing element, typically a central processing unit (CPU), and some form of memory.
The processing element carries out arithmetic and logic operations, and
a sequencing and control unit can change the order of operations in
response to stored information. Peripheral devices allow information to
be retrieved from an external source, and the result of operations saved
and retrieved. Mechanical analog computers started appearing in first century and were later used in the medieval era for astronomical calculations. In World War II, mechanical analog computers were used for specialized military applications.
During this time the first electronic digital computers were developed. Originally they were the size of a large room, consuming as much power as several hundred modern personal computers (PCs). Modern computers based on integrated circuits are millions to billions of times more capable than the early machines, and occupy a fraction of the space. Simple computers are small enough to fit into mobile devices, and mobile computers can be powered by small batteries. Personal computers in their various forms are icons of the Information Age and are what most people think of as “computers.” However, the embedded computers found in many devices from MP3 players to fighter aircraft and from toys to industrial robots are the most numerous.
History:- Pre-Twentieth Century
The Ishango
Devices have been used to aid computation for thousands of years, mostly using one-to-one correspondence with fingers. The earliest counting device was probably a form of tally stick. Later record keeping aids throughout the Fertile Crescent
included calculi (clay spheres, cones, etc.) which represented counts
of items, probably livestock or grains, sealed in hollow unbaked clay
containers.The use of counting rods is one example.
- Suanpan (the number represented on this abacus is 6,302,715,408)
The abacus was early used for arithmetic tasks. What we now call the Roman abacus was used in Babylonia as early as 2400 BC. Since then, many other forms of reckoning boards or tables have been invented. In a medieval European counting house,
a checkered cloth would be placed on a table, and markers moved around
on it according to certain rules, as an aid to calculating sums of
money.
- The ancient Greek-designed Antithetical mechanism, dating between 150 to 100 BC, is the
World's oldest analog computer.
The Antikythera mechanism is believed to be the earliest mechanical analog "computer", according to Derek J. de Solla Price. It was designed to calculate astronomical positions. It was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to circa
100 BC. Devices of a level of complexity comparable to that of the
Antikythera mechanism would not reappear until a thousand years later. Many mechanical aids to calculation and measurement were constructed for astronomical and navigation use. The planisphere was a star chart invented by Abū Rayhān al-Bīrūnī in the early 11th century. The astrolabe was invented in the Hellenistic world in either the 1st or 2nd centuries BC and is often attributed to Hipparchus. A combination of the planisphere and dioptra, the astrolabe was effectively an analog computer capable of working out several different kinds of problems in spherical astronomy. An astrolabe incorporating a mechanical calendar computer and gear-wheels was invented by Abi Bakr of Isfahan, Persia in 1235.Abū Rayhān al-Bīrūnī invented the first mechanical geared lunisolar calendar astrolabe,an early fixed-wired knowledge processing machine with a gear train and gear-wheels, circa 1000 AD.
The sector,
a calculating instrument used for solving problems in proportion,
trigonometry, multiplication and division, and for various functions,
such as squares and cube roots, was developed in the late 16th century
and found application in gunnery, surveying and navigation.
The planimeter was a manual instrument to calculate the area of a closed figure by tracing over it with a mechanical linkage.
A slide rule
The slide rule was invented around 1620–1630, shortly after the publication of the concept of the logarithm.
It is a hand-operated analog computer for doing multiplication and
division. As slide rule development progressed, added scales provided
reciprocals, squares and square roots, cubes and cube roots, as well as transcendental functions such as logarithms and exponentials, circular and hyperbolic trigonometry and other functions.
Aviation is one of the few fields where slide rules are still in
widespread use, particularly for solving time–distance problems in light
aircraft. To save space and for ease of reading, these are typically
circular devices rather than the classic linear slide rule shape.
A popular example is the E6B.
In the 1770s Pierre Jaquet-Droz, a Swiss watchmaker, built a mechanical doll (automata)
that could write holding a quill pen. By switching the number and order
of its internal wheels different letters, and hence different messages,
could be produced. In effect, it could be mechanically "programmed" to
read instructions. Along with two other complex machines, the doll is at
the Musée d'Art et d'Histoire of Neuchâtel, Switzerland, and still operates. The tide-predicting machine invented by Sir William Thomson
in 1872 was of great utility to navigation in shallow waters. It used a
system of pulleys and wires to automatically calculate predicted tide
levels for a set period at a particular location.
The differential analyse, a mechanical analog computer designed to solve differential equations by integration, used wheel-and-disc mechanisms to perform the integration. In 1876 Lord Kelvin
had already discussed the possible construction of such calculators,
but he had been stymied by the limited output torque of the ball-and-disk integrators. In a differential analyzer, the output of one integrator drove the input of the next integrator, or a graphing output. The torque amplifier was the advance that allowed these machines to work. Starting in the 1920s, Vannevar Bush and others developed mechanical differential analyzers.
Thanks for Reading and Watching.
Prakand.
