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Review and history of architecture of computers.

The computer facilities are the most important component of process of calculations and data processing. The first adaptations for calculations were the calculating sticks which are used today in initial classes of many schools for training the account. Such adaptations were used by the dealers and accountants of that time.

Gradually from the elementary adaptations for the account difficult devices were used more and more: abacuses (scores), slide rule, mechanical arithmometer, and electronic computer. Naturally, the productivity and speed of the account of modern computers already surpass the possibilities of the most outstanding counter.

Early adaptations and devices for the account

When the people bothered to keep count by means of bending of fingers, they invented abacuses. The mankind learned to use the elementary calculating adaptations one thousand years ago. The necessity to define the quantity of subjects used in barter was the most demanded. The use of a weight equivalent of a changed subject that didn't demand exact recalculation of quantity of its components was one of the simplest decisions. For these purposes the elementary balance scales, one of the first devices for quantitative determination of weight were used.

Yupana (abacuses of monks) allegedly used numbers of Fibonacci. The principle of equivalence was widely used and in another, familiar for many, the elementary calculating devices of Abacuses or Scores. The quantity of counted-up subjects corresponded to number of the moved bones of this tool.

Beads were rather difficult adaptation for the account; they were applied in the practice of many religions. The believer as counted the number of the said prayers on the grains of beads, and after the pass of a cycle of beads he moved on a separate tail the special grains counters meaning number of counted circles.

Asterisks and gears were heart of mechanical devices for the account. With the invention of cogwheels there were also much more difficult devices of performance of calculations. The Anti Kiter mechanism found at the beginning of the XX century on the place of crash of the antique vessel approximately in the 65th year BC (on other sources in 80 or even to the 87th year BC) even was able to model the movement of planets. However, with antiquity leaving the skills of creation of such devices were forgotten; about one and a half thousand years ago people learned to create again similar mechanisms.

In 1623 Wilhelm Shikard created «Counting hours» — the first mechanical calculator which was able to carry out four arithmetic actions. The device was called «Counting hours» because the operation of the mechanism was based on use of asterisks and gears in real clocks. Practical use is the invention found in hands of friend Shikard, the philosopher and astronomer Johann Kepler.

It was followed by Blaise Pascal's machine («Pascal», 1642) and Gottfried Wilhelm Leibniz.

Approximately in 1820 Charles Xavier Thomas created the first successful, serially let out mechanical calculator – Thomas's Arithmometer which could put, read, multiply and divide. Generally it was based on Leibniz's work. The mechanical calculators considering decimal numbers were used to the 1970th.



Leibniz also described binary notation, the central component of all modern computers. However up to the 1940th, many subsequent developments (including Charles Babbage's machine and even ENIAC, 1945) were based on the decimal system which was more difficult in realization.

John Nipper noticed that multiplication and division of numbers can be executed by addition and subtraction, respectively, logarithms of these numbers. Real numbers can be presented by intervals of length on a ruler, and it laid down in the basis of calculations by means of a slide rule that allowed carrying out the multiplication and division much quicker. Slide rules were used by several generations of engineers and other professionals till to emergence of pocket calculators. Engineers of Apollo program sent the person on the Moon after the execution of all calculations on slide rules, many of which demanded accuracy in 3-4 signs.

For drawing up of the first logarithmic tables of Nipper needed the implementation of all sets of operations of multiplication, and at the same time he developed Nipper’s sticks.

Punched card system

In 1801 Joseph Mary Jakkar developed the weaving loom in which the embroidered pattern was defined by punched cards. A series of cards could be replaced, and change of a pattern didn't demand changes in mechanics of the machine. It was an important milestone in the history of programming.

In 1838 Charles Babbage passed over from the development of the differential machine to design of more difficult analytical machine which principles of programming directly went back to Jakkar's punched cards.

In 1890 the Bureau of Census of the USA used punched cards and mechanisms the sorting (tabulators) developed by Herman Hollerith to process the data flow of ten years' census transferred under the mandate according to the Constitution. The company Hollerith finally became IBM kernel. This corporation developed technology of punched cards in the powerful tool for business data processing and let out the extensive line of the specialized equipment for their record. By 1950 the IBM technology became ubiquitous in the industry and the government. The prevention printed on the majority of cards, «not to turn off, not to braid and not to tear» became the motto of a post-war era.

In many computer solutions the punched card were used to (and after) the end of the 1970th. For example, students of engineering and scientific specialties at many universities around the world could send their program teams in the local computer center in the form of a set of cards, one card for a program line, and then the turn for processing should wait, for compilation and implementation of the program. Subsequently after listing of any results noted by the identifier of the applicant, they were located in a final tray out of the computer center. In many cases these results included only error message listing in syntax of the program, demanding other cycle editing – compilation – execution.

The 1835-1900th: the first programmed machines

Defining feature of «the universal computer» is a programmability that allows the computer to emulate any other calculating system only replacement of the kept sequence of instructions.

In 1835 Charles Babbage described the analytical machine. In «analytical» the principles which have become fundamental to computer facilities are put:

1. automatic performance of operations

2. work on the program entered «under way»

3. need of the special device of memory for data storage (Babbage called it «warehouse»)

It was the project of the computer of general purpose with the application of punched cards as the carrier of entrance data and the program, and also the steam engine as a power source. Use of the gear wheel for performance of mathematical functions was one of key ideas.

The part differential of Babbage machine collected after his death by his son from parts found in laboratory.

The use of punched cards for the machine calculating and printing logarithmic tables with big accuracy (that is for the specialized machine) was his initial idea. Further these ideas were developed for the machine of general purpose – for his «analytical machine».

Before the Second World War mechanical and electric analog computers were considered as the most modern machines, and many considered that as future of computer facilities. Analog computers used advantages of that mathematical properties of the phenomena of small scale – the provision of wheels or electric tension and a current – are similar to mathematics of other physical phenomena, for example such as ballistic trajectories, inertia, a resonance, energy transfer, the inertia moment, etc. They modeled these and other physical phenomena values of electric tension and a current.

British «Colossus»

The British Colossus was used for breaking the German codes during the Second World War. «Colossus» became the first completely electronic computer. A large number of electro vacuum lamps were used, input of information was carried out from a punched tape. «Colossus» could be adjusted on performance of various operations of Boolean logic, but it wasn't full-turing machine. Besides Colossus Mk I, nine more Mk II models were collected. Information on existence of this machine was kept in a secret till 1970th Winston Churchill personally signed the order on car destruction on a part, not exceeding in the size of a human hand. Because of the privacy, «Colossus» isn't mentioned in many works on stories of computers.

American developments

In 1937 Claude Shannon showed that there is a compliance one - to - one between concepts of Boolean logic and some electronic schemes which received the name «logic gates» which are everywhere used now in digital computers. Working in MTI in the main work, it showed that electronic communications and switches could represent expression of Boolean algebra. So the work of A Symbolic Analysis of Relay and Switching Circuits was created on the basis for practical design of digital schemes.

ENIAC carried out ballistic calculations and consumed capacity in 160 kW. ENIAC (Electronic Numerical Integrator and Computer – the Electronic numerical integrator and the calculator) – the first large-scale electronic digital computer which could be reprogrammed for the solution of a full range of tasks, often known as the first electronic computer of general purpose, publicly proved applicability of electronics for large-scale calculations. It became the key moment in development of computers, first of all because of a huge gain in speed of calculations, but also and because of the appeared possibilities for miniaturization. Created under the direction of John Mochli and J. Presper Eckert, this machine was in 1000 of times quicker, than all other machines of that time. Development «ENIAC» lasted from 1943 to 1945. When this project was offered, many researchers were convinced that among thousand fragile electro vacuum lamps many would burn down so often that «ENIAC» too much time would stand idle under repair and by that, it would be almost useless. Nevertheless, by the real machine it was possible to carry out some thousand operations a second within several hours, before the next failure because of the burned-down lamp.

Having processed Eckert and Mochli's ideas, and also, having estimated the restrictions «ENIAC», John von Neumann wrote widely quoted report describing the project of the computer (EDVAC) in which both the program, and data were stored in uniform universal memory. Principles of creation of this machine became known under the name «von Neumann’s architecture» and formed a basis for development of the first rather flexible, universal digital computers.

The first generation of computers with von Neumann's architecture

In 1956 IBM sold for the first time the device for information storage on magnetic disks – RAMAC (Random Access Method of Accounting and Control). It used 50 metal disks in diameter 24 inches, on 100 paths from each party. The device stored to 5 MB of data and coasted for $10 000 for MB. (In 2006, similar devices of data storage – hard disks – cost about $0,001 for Mb.)

The 1950th – the beginning of the 1960th: second generation

The first Soviet serial semi-conductor Computer of the spring and Snow steel were produced from 1964 to 1972. Peak productivity of the Snow Computer made 300 000 operations in a second. Machines were made on the basis of transistors with clock frequency of 5 MHz. In total 39 Computers were produced.

It is considered that the best domestic COMPUTER of the 2nd generation BESM-6 was created in 1966. In architecture BESM-6 the principle of combination of performance of teams (to 14 single-address machine teams could be at different stages of performance) for the first time was widely used. Mechanisms of interruption, protection of memory and other innovative decisions allowed using BESM-6 in a multiprogramming mode and a mode of division of time. The COMPUTER had 128 KB of random access memory on ferrite cores and external memories on magnetic drums and a tape. BESM-6 worked with clock frequency of 10 MHz and records the productivity – about 1 million operations a second. In total 355 COMPUTERS were produced.

The 1960th and further: the third and subsequent generations

Integrated chips contain many hundreds millions transistors. The integrated scheme is a micro miniature chain of a certain functional purpose which by means of special technology takes place on very small silicon (or any another suitable on properties) a plate – a basis. The area of such scheme is 1-3 cm2, but on the functionality the integrated scheme is equivalent to hundreds and thousands transistor elements.

Rapid growth of use of computers began with so-called «the 3rd generation» computers. The beginning of the invention of integrated schemes independent from each other were invented by Nobel Prize winner Jack Kilby and Robert Noyce. Later it led to the microprocessor invention of Tad Hoff (Intel Company).

During the 1960th a certain overlapping of technologies of the 2nd and 3rd generations was observed. At the end of 1975, in Sperry Univac production of cars of the 2nd generation, such as UNIVAC 494 was preceded.

Emergence of microprocessors led to development of microcomputers – small inexpensive computers which the small companies or certain people could own. Microcomputers, representatives of the fourth generation, first of which appeared in the 1970th, became the universal phenomenon in the 1980th and later. Steve Wozniak, one of founders of Apple Computer, became known as the developer of the first mass home computer, and later – the first personal computer. Computers on the basis of microcomputer architecture with the possibilities added from their big colleagues, now dominate in the majority of segments of the market.

 


Date: 2015-12-24; view: 158


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