Computer

• 1. Human Calculators And The Word Computer

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  In 1613, the English writer Richard Brathwait published a book called The Yong Mans Gleanings. He used the phrase truest computer of Times to describe a person who calculated dates and reduced days into numbers. This usage referred to a human computer, a person who carried out calculations or computations by hand. The word continued to have this meaning until the middle of the 20th century. During the latter part of that period, women were often hired as computers because they could be paid less than their male counterparts. By 1943, most human computers were women working in offices and government agencies. They performed complex arithmetic tasks using mechanical aids like slide rules or simple paper methods. The Online Etymology Dictionary gives the first attested use of computer in the 1640s, meaning one who calculates. This is an agent noun from compute. The online source states that the use of the term to mean calculating machine of any type is from 1897. The modern use of the term, to mean programmable digital electronic computer, dates from 1945 under this name. A theoretical sense existed from 1937, as Turing machine.

• 2. Mechanical Engines And Analog Devices

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  Devices have been used to aid computation for thousands of years, mostly using one-to-one correspondence with fingers. The earliest counting device was most likely a form of tally stick. Later record keeping aids throughout the Fertile Crescent included calculi clay spheres which represented counts of items. These calculi were in use in Iraq for primitive accounting systems as early as 3200, 3000 BCE. Balanced accounting was in use by 3000, 2350 BCE, and a sexagesimal number system was in use 2350, 2000 BCE. The abacus was initially used for arithmetic tasks. The Roman abacus was developed from devices used in Babylonia as early as 2400 BCE. 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. The Antikythera mechanism, dating back to ancient Greece circa 200, 80 BCE, is an early analog computing device. It was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera. This device was designed to calculate astronomical positions. Devices of comparable complexity to the Antikythera mechanism would not reappear until the fourteenth century. The slide rule was invented around 1620, 1630, by the English clergyman William Oughtred. It is a hand-operated analog computer for doing multiplication and division.

• 3. Electromechanical And Electronic Breakthroughs

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  Charles Babbage, an English mechanical engineer and polymath, originated the concept of a programmable computer. He conceptualized and invented the first mechanical computer in the early 19th century. After working on his difference engine he announced his invention in 1822, in a paper to the Royal Astronomical Society. He also designed to aid in navigational calculations, in 1833 he realized that a much more general design, an analytical engine, was possible. The input of programs and data was to be provided to the machine via punched cards. The machine was about a century ahead of its time. All the parts for his machine had to be made by hand. Eventually, the project was dissolved with the decision of the British Government to cease funding. In 1941, Zuse followed his earlier machine up with the Z3, the world's first working electromechanical programmable, fully automatic digital computer. The Z3 was built with 2000 relays, implementing a 22 bit word length that operated at a clock frequency of about 5, 10 Hz. Program code was supplied on punched film while data could be stored in 64 words of memory. During World War II, the British code-breakers at Bletchley Park achieved a number of successes at breaking encrypted German military communications. Max Newman and his colleagues commissioned Flowers to build the Colossus. He spent eleven months from early February 1943 designing and building the first Colossus.

• 4. Transistors And Integrated Circuits

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  John Bardeen and Walter Brattain, while working under William Shockley at Bell Labs, built the first working transistor, the point-contact transistor, in 1947. From 1955 onwards, transistors replaced vacuum tubes in computer designs, giving rise to the second generation of computers. Compared to vacuum tubes, transists have many advantages: they are smaller, and require less power than vacuum tubes, so give off less heat. Junction transistors were much more reliable than vacuum tubes and had longer, indefinite, service life. The metal-oxide-silicon field-effect transistor MOSFET was invented at Bell Labs between 1955 and 1960. It was the first truly compact transistor that could be miniaturized and mass-produced for a wide range of uses. With its high scalability, and much lower power consumption and higher density than bipolar junction transistors, the MOSFET made it possible to build high-density integrated circuits. The next great advance in computing power came with the advent of the integrated circuit IC. Geoffrey W.A. Dummer presented the first public description of an integrated circuit at the Symposium on Progress in Quality Electronic Components in Washington DC, on the 7th of May 1952. Jack Kilby recorded his initial ideas concerning the integrated circuit in July 1958, successfully demonstrating the first working integrated example on the 12th of September 1958.

• 5. Microprocessors And Modern Hardware

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  The development of the MOS integrated circuit led to the invention of the microprocessor, and heralded an explosion in the commercial and personal use of computers. While the subject of exactly which device was the first microprocessor is contentious, it is largely undisputed that the first single-chip microprocessor was the Intel 4004. This chip was designed and realized by Federico Faggin with his silicon-gate MOS IC technology, along with Ted Hoff, Masatoshi Shima and Stanley Mazor at Intel. In the early 1970s, MOS IC technology enabled the integration of more than 10,000 transistors on a single chip. System on a Chip SoCs are complete computers on a microchip the size of a coin. They may or may not have integrated RAM and flash memory. If not integrated, the RAM is usually placed directly above or below the SoC. Since ENIAC in 1945, computers have advanced enormously, with modern SoCs being the size of a coin while also being hundreds of thousands of times more powerful than ENIAC. A general-purpose computer has four main components: the arithmetic logic unit ALU, the control unit, the memory, and the input and output devices.

• 6. Software Engineering And Programming Languages

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  Software is the part of a computer system that consists of the encoded information that determines the computer's operation. It includes computer programs, libraries and related non-executable data. When software is stored in hardware that cannot easily be modified, such as with BIOS ROM in an IBM PC compatible computer, it is sometimes called firmware. The defining feature of modern computers which distinguishes them from all other machines is that they can be programmed. That is to say that some type of instructions the program can be given to the computer, and it will process them. Modern computers based on the von Neumann architecture often have machine code in the form of an imperative programming language. In practical terms, a computer program may be just a few instructions or extend to many millions of instructions. Large computer programs consisting of several million instructions may take teams of programmers years to write. Bugs errors in computer programs are called bugs. They may be benign and not affect the usefulness of the program, or have only subtle effects. Admiral Grace Hopper, an American computer scientist and developer of the first compiler, is credited for having first used the term bugs in computing after a dead moth was found shorting a relay in the Harvard Mark II computer in September 1947.

• 7. Networking And Global Connectivity

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  Computers have been used to coordinate information between multiple physical locations since the 1950s. The U.S. military's SAGE system was the first large-scale example of such a system. It led to a number of special-purpose commercial systems such as Sabre. In the 1970s, computer engineers at research institutions throughout the United States began to link their computers together using telecommunications technology. The effort was funded by ARPA now DARPA, and the computer network that resulted was called the ARPANET. Logic gates are a common abstraction which can apply to most of the above digital or analog paradigms. The ability to store and execute lists of instructions allows computers to communicate across vast distances. Modern desktop computers contain many smaller computers that assist the main CPU in performing I/O. A 2016-era flat screen display contains its own computer circuitry. Computers power the Internet, which links billions of computers and users. Early computers were meant to be used only for calculations. Simple manual instruments like the abacus have aided people in doing calculations since ancient times. The speed, power, and versatility of computers have been increasing dramatically ever since then, with transistor counts increasing at a rapid pace.