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2015-12-27 回答

computer is a computer device for high-speed computation, numerical calculations can be carried out, they can be logically calculated, also has a memory function. It is able to follow the program runs, automatic, high-speed processing of massive data, modern intelligent electronic devices. Hardware and software systems are composed of a computer does not install any software called bare metal. Can be divided into supercomputers, industrial control computers, network computers, personal computers, embedded computers five, more advanced computers have biological computer, photonic computers, quantum computers.

Computer inventor John von Neumann. Computer is one of the 20th century's most advanced science and technology invention for the production of human and social activities had a very important impact, and the rapid development of a strong vitality. Its applications extend from the initial military research applied to all areas of society, has become a huge computer industry, led the worldwide technological progress, which led to profound social change, the computer has been throughout the general schools, enterprises institutions, enter homes of ordinary people, become an indispensable tool in the information society.

Computer applications become increasingly common in China, after the reform and opening up, the number of Chinese computer users continue to rise, and constantly improve the level of application, especially the application of the Internet, communications, multimedia and other fields have achieved good results. From 1996 to 2009, the number of computer users increased from the original 6.3 million to 67.1 million units, the number of networked computers increased from 29,000 sets the stage rose to 59.4 million units. Internet users has reached 316 million, there are 670 million mobile wireless Internet users, mobile Internet users reached 117 million, the first in the world.

Calculation tools undergone evolution from simple to complex, from lower to higher different stages, for example,

ENIAC computer

For example, from "Jieshengjishi" in knots to count chips, abacus slide rule, mechanical computers. They play their historical role in different historical periods, but also inspired the development of computer and design ideas.

In 1889, American scientist Herman Hollerith developed electricity-based electric tabulating machine for storing calculations.

In 1930, American scientist Vannevar Bush made the world's first analog computer.

February 14, 1946, by the US military to customize the world's first computer "Electronic Numerical Integrator and Computer" (ENIAC Electronic Numerical And Calculator) come out at the University of Pennsylvania. ENIAC (Chinese name: Eni Ake) was an American Oberding weapons test site in order to meet the need to calculate the trajectory and developed into, this calculator uses the 17,840 tubes, the size of 80 feet × 8 feet and weigh up to 28t ( tonnes), power consumption is 170kW, the operation speed of 5,000 times per second adder, cost about $ 487,000. ENIAC advent of epoch-making significance, indicating the arrival of the computer age. After 60 years, computer technology at an alarming rate, there is no one technology can increase the cost performance of six orders of magnitude in 30 years.

1st generation: digital tube machine (1946- 1958)

Hardware, logic element is used vacuum tubes, the main memory using mercury delay lines

Tube digital computer

Cathode ray oscilloscope static memory, drum core; external memory uses a tape. Software uses a machine language, assembly language. Applications based on military and scientific computing.

It characterized by small, high power consumption and poor reliability. Slow (typically thousands to tens of thousands of times per second), the price is expensive, but for the future of computer development has laid a foundation.

2nd Generation: Transistors digital machine (1958- 1964)

OS hardware side, high-level language and compiler. Applications to scientific computing and transaction processing-based, and began to enter the field of industrial control. Features are smaller in size, lower power consumption, improved reliability, operation speed (typically 100,000 times per second, up to three million times), performance than the first generation of computers has greatly improved.

3rd generation: integrated digital machine (1964- 1970)

Hardware, logic components used in small-scale integrated circuits (MSI, SSI), main memory is still using core. Software as well as the emergence of time-sharing operating system architecture, large-scale process design methods. Feature is faster (typically millions of times per second to tens of millions of times), and the reliability has improved significantly, further price drops, product toward the universal, serialization and standardization. Applications began to enter the field of image processing text and graphics processing.

4th Generation: LSI Machine (1970-present)

Hardware, logic components using large-scale and ultra large scale integrated circuit (LSI and VLSI). The emergence of database management software systems, network management systems and object-oriented language. It characterized by 1971 the world's first microprocessor was born in Silicon Valley, creating a new era of the microcomputer. Applications from scientific computing, transaction management, process control gradually families.

Since the development of integrated technology, higher levels of integration of semiconductor chips, each chip can accommodate tens of thousands or even millions of transistors, and can be operational and controller are concentrated on a single chip, which appeared in the microprocessor, and you can use microprocessors and large-scale, ultra large scale integrated circuit assembled into a microcomputer, it is what we often say microcomputer or PC. Microcomputers small, cheap, easy to use, but its function and operation speed has reached or even exceeded the previous mainframe computers. On the other hand, the use of large-scale, VLSI fabrication of a variety of logic chips, has made the volume is not great, but the computing speed of up to one hundred million or even billions of times a supercomputer. Following our successful development operation in 1983 after a million times per second, this type of supercomputer Milky Way Ⅰ, and in 1993 successfully developed billions of operations per second Galaxy Ⅱ-purpose parallel supercomputers. This period also produced a new generation of programming languages and database management systems and network software.

With the physical element, the change of the device, not only the host computer through the upgrading of its external devices are constantly change. Such as external memory, from the initial development of the cathode ray tube display core, drum, and later developed into versatile disk, now appeared smaller, larger, faster CD-ROM