ComputerA computer is a machine tha

Computer

A computer is a machine that manipulates data according to a list of instructions.

The first devices that resemble modern computers date to the mid-20th century (around 1940 - 1945), although the computer concept and various machines similar to computers existed earlier. Early electronic computers were the size of a large room, consuming as much power as several hundred modern personal computers. Modern computers are based on tiny integrated circuits and are millions to billions of times more capable while occupying a fraction of the space. Today, simple computers may be made small enough to fit into a wristwatch and be powered from a watch battery. Personal computers in various forms are icons of the Information Age and are what most people think of as "a computer"; however, the most common form of computer in use today is the embedded computer. Embedded computers are small, simple devices that are used to control other devices — for example, they may be found in machines ranging from fighter aircraft to industrial robots, digital cameras, and children's toys.

The ability to store and execute lists of instructions called programs makes computers extremely versatile and distinguishes them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore, computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks given enough time and storage capacity.


History of computing

The Jacquard loom was one of the first programmable devices.

It is difficult to identify any one device as the earliest computer, partly because the term "computer" has been subject to varying interpretations over time. Originally, the term "computer" referred to a person who performed numerical calculations (a human computer), often with the aid of a mechanical calculating device.

The history of the modern computer begins with two separate technologies - that of automated calculation and that of programmability.

Examples of early mechanical calculating devices included the abacus, the slide rule and arguably the astrolabe and the Antikythera mechanism (which dates from about 150-100 BC). The end of the Middle Ages saw a re-invigoration of European mathematics and engineering, and Wilhelm Schickard's 1623 device was the first of a number of mechanical calculators constructed by European engineers. However, none of those devices fit the modern definition of a computer because they could not be programmed.

Hero of Alexandria (c. 10 – 70 AD) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions - and when.[3] This is the essence of programmability. In 1801, Joseph Marie Jacquard made an improvement to the textile loom that used a series of punched paper cards as a template to allow his loom to weave intricate patterns automatically. The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early, albeit limited, form of programmability.

It was the fusion of automatic calculation with programmability that produced the first recognisable computers. In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer that he called "The Analytical Engine".[4] Due to limited finances, and an inability to resist tinkering with the design, Babbage never actually built his Analytical Engine.

Large-scale automated data processing of punched cards was performed for the U.S. Census in 1890 by tabulating machines designed by Herman Hollerith and manufactured by the Computing Tabulating Recording Corporation, which later became IBM. By the end of the 19th century a number of technologies that would later prove useful in the realization of practical computers had begun to appear: the punched card, Boolean algebra, the vacuum tube (thermionic valve) and the teleprinter.

During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers.



A succession of steadily more powerful and flexible computing devices were constructed in the 1930s and 1940s, gradually adding the key features that are seen in modern computers. The use of digital electronics (largely invented by Claude Shannon in 1937) and more flexible programmability were vitally important steps, but defining one point along this road as "the first digital electronic computer" is difficult (Shannon 1940). Notable achievements include:

EDSAC was one of the first computers to implement the stored program (von Neumann) architecture.
Konrad Zuse's electromechanical "Z machines". The Z3 (1941) was the first working machine featuring binary arithmetic, including floating point arithmetic and a measure of programmability. In 1998 the Z3 was proved to be Turing complete, therefore being the world's first operational computer.
The non-programmable Atanasoff–Berry Computer (1941) which used vacuum tube based computation, binary numbers, and regenerative capacitor memory.
The secret British Colossus computer (1944), which had limited programmability but demonstrated that a device using thousands of tubes could be reasonably reliable and electronically reprogrammable. It was used for breaking German wartime codes.
The Harvard Mark I (1944), a large-scale electromechanical computer with limited programmability.
The U.S. Army's Ballistics Research Laboratory ENIAC (1946), which used decimal arithmetic and is sometimes called the first general purpose electronic computer (since Konrad Zuse's Z3 of 1941 used electromagnets instead of electronics). Initially, however, ENIAC had an inflexible architecture which essentially required rewiring to change its programming.

Several developers of ENIAC, recognizing its flaws, came up with a far more flexible and elegant design, which came to be known as the stored program architecture or von Neumann architecture. This design was first formally described by John von Neumann in the paper "First Draft of a Report on the EDVAC", published in 1945. A number of projects to develop computers based on the stored program architecture commenced around this time, the first of these being completed in Great Britain. The first to be demonstrated working was the Manchester Small-Scale Experimental Machine (SSEM) or "Baby". However, the EDSAC, completed a year after SSEM, was perhaps the first practical implementation of the stored program design. Shortly thereafter, the machine originally described by von Neumann's paper—EDVAC—was completed but did not see full-time use for an additional two years.

Nearly all modern computers implement some form of the stored program architecture, making it the single trait by which the word "computer" is now defined. By this standard, many earlier devices would no longer be called computers by today's definition, but are usually referred to as such in their historical context. While the technologies used in computers have changed dramatically since the first electronic, general-purpose computers of the 1940s, most still use the von Neumann architecture. The design made the universal computer a practical reality.

Microprocessors are miniaturized devices that often implement stored program CPUs.

Vacuum tube-based computers were in use throughout the 1950s, but were largely replaced in the 1960s by transistor-based devices, which were smaller, faster, and cheaper, used less power and were more reliable. These factors allowed computers to be produced on an unprecedented commercial scale. By the 1970s, the adoption of integrated circuit technology and the subsequent creation of microprocessors such as the Intel 4004 caused another leap in size, speed, cost and reliability. By the 1980s, computers had become sufficiently small and cheap to replace simple mechanical controls in domestic appliances such as washing machines. Around the same time, computers became widely accessible for personal use by individuals in the form of home computers and the now ubiquitous personal computer. In conjunction with the widespread growth of the Internet since the 1990s, personal computers are becoming as common as the television and the telephone and almost all modern electronic devices contain a computer of some kind.

Stored program architecture

The defining feature of modern computers which distinguishes them from all other machines is that they can be programmed. That is to say that a list of instructions (the program) can be given to the computer and it will store them and carry them out at some time in the future.

In most cases, computer instructions are simple: add one number to another, move some data from one location to another, send a message to some external device, etc. These instructions are read from the computer's memory and are generally carried out (executed) in the order they were given. However, there are usually specialized instructions to tell the computer to jump ahead or backwards to some other place in the program and to carry on executing from there. These are called "jump" instructions (or branches). Furthermore, jump instructions may be made to happen conditionally so that different sequences of instructions may be used depending on the result of some previous calculation or some external event.

Результаты (русский) 3:

компьютеркомпьютер, это машина, которая манипулирует данными по списку инструкций.первых устройств, напоминающих современные компьютеры до середины двадцатого века (в 1940 - 1945), хотя компьютерные концепции и различные машины похожи на компьютеры, существовали и ранее.первые электронные компьютеры были размером с большую комнату, потреблять столько же энергии, как несколько сотен современных персональных компьютеров.современные компьютеры, основаны на крошечные интегральных схем и миллионы и миллиарды раз более эффективно, хотя оккупационные часть пространства.сегодня просто компьютеры могут быть достаточно маленькими, чтобы вписаться в наручные часы и часы, питание от батареи.персональные компьютеры в различных формах являются иконами в век информации, и то, что большинство людей считают "компьютер", однако, наиболее распространенной формой компьютера, используемых в настоящее время является встроенный компьютер.встроенный компьютер небольших простых устройств, которые используются для контроля над другими устройствами - например, их можно найти в машинах, начиная от истребителей для промышленных роботов, цифровые камеры, и детские игрушки.умение хранить и выполнить инструкции называется программы списки делает компьютеры крайне разностороннего и отличает их от калькуляторы.церковь - тьюринга диссертация математической заявление эта универсальность: любой компьютер с определенного минимального потенциала - это, в принципе, способные выполнять те же задачи, что любой другой компьютер может выполнять.таким образом, компьютеры с возможностями и сложности, начиная от того, что персональный цифровой помощник суперкомпьютер могут выполнять те же вычислительных задач достаточно времени и мощностей для хранения.история вычислительнойThe жаккардовый ткацкий станок был одним из первых программных средств.трудно определить какие - либо одного устройства, как компьютер, отчасти потому, что термин "компьютер" стал предметом различных толкований.первоначально термин "компьютер" обозначается лицо, которое выполняет числовых расчетов (человек - компьютер), часто при помощи механического расчета устройства.история современных компьютерных начинается с двух отдельных технологий - это автоматизированных расчетов и что programmability.примеры первых механических расчета устройства были счеты, слайд - норма, и, возможно, астролябия и антикитерский механизм (датируется примерно 150-100 до н.э.).в конце средневековья видел повторной активизации европейских математики и инженерных и вильгельм шиккард - 1623 устройства был первый ряд механических калькуляторов, изготовленные европейских инженеров.однако ни одна из этих устройств для современного определения компьютер, потому что они не могут быть запрограммированы.герон (с 10 - 70 ad) построил механический театр, который провела играть прочного 10 минут и управляет сложной системе тросов и барабаны, которые, возможно, будут рассматриваться в качестве способа определения того, какие части механизма, выполнены, какие действия - и когда [3]. это и есть programmability.в 1801, жозеф мари жаккар, улучшение текстильной ткацкий станок, который используется ряд ударил бумажных карт в качестве шаблона, чтобы его станок, плести сложную структуру автоматически.в результате жаккардовый ткацкий станок, является важным шагом в разработке компьютеров, поскольку использование карт, чтобы определить, плетеные узоры кулаками можно рассматривать в качестве рано, хотя и ограниченным, форма programmability.это слияние автоматического расчета с programmability, выпустил первую узнаваем компьютеров.в 1837 году чарльз бэббидж была первой концепции и разработке полностью программируемых механические компьютер, который он назвал "аналитический двигатель". [4] в связи с ограниченными финансовыми ресурсами, и неспособность противостоять возился с дизайном, так и не построил свой аналитический бэббидж двигателя.крупномасштабные автоматической обработки данных о ударил карты были произведены для переписи населения сша в 1890 году составил машин, разработанных холлерит, герман и производимые компьютерного табулирования регистрации корпорации, который позже стал IBM.к концу XIX века ряд технологий, которые затем оказаться полезными в реализации практических компьютеры стали появляться: перфокарта, булева алгебра, вакуумный (приблизительно клапана) и телетайп.в первой половине 20 - го века многие научных вычислений, потребности были удовлетворены все более изощренные аналоговых компьютеры, в которых используется прямое механической или электрические модели проблемы в качестве основы для расчета.однако это не программируемый и, как правило, не хватало универсальности и точность современных цифровых вычислительных машин.череда все более мощную и гибкую вычислительных устройств, было построено в 1930 - 1940 - е годы, постепенно добавляя ключевые элементы, которые рассматриваются в современных компьютерах.использование цифровой электроники (в основном, придуманный клод шеннон в 1937 году) и более гибкие programmability являются жизненно важными шагами, но по определению один момент