What are the four eras that computers have gone through?

The four eras that computers have experienced are: 1. The first generation is the tube digital computer from 1946 to 1958; 2. The second generation is the transistor digital computer from 1958 to 1964; 3. The third generation The first generation is the integrated circuit digital computer from 1964 to 1970; the 4th generation is the large-scale integrated circuit computer from 1970 to the present.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

Computer, commonly known as computer, is a modern electronic computing machine used for high-speed calculations. It can perform numerical calculations, logical calculations, and also has storage and memory functions. It is a modern intelligent electronic device that can run according to the program and process massive data automatically and at high speed.

The evolution of calculation tools has gone through different stages from simple to complex, from low-level to advanced, such as from the knots in "knotting notes" to arithmetic chips, abacus slide rules, mechanical computers, etc. They played their respective historical roles in different historical periods, and also inspired the development ideas of modern electronic computers.

In 1889, American scientist Herman Hollery developed an electric tabulating machine based on electricity to store calculation data.

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

On February 14, 1946, the world's first electronic computer "Electronic Numerical And Calculator" (ENIAC Electronic Numerical And Calculator) customized by the U.S. military was launched at the University of Pennsylvania. ENIAC (Chinese name: ENIAC) was developed by the Auberdine Weapons Testing Site in the United States to meet the needs of calculating ballistics. This calculator uses 17,840 electron tubes, is 80 feet × 8 feet in size, and weighs 28t ( tons), the power consumption is 170kW, its computing speed is 5,000 addition operations per second, and the cost is approximately US$487,000. The advent of ENIAC has epoch-making significance, indicating the arrival of the electronic computer era. In the next 60 years or so, computer technology has developed at an alarming rate. The performance-price ratio of any technology can increase by 6 orders of magnitude in 30 years.

1st Generation: Vacuum Tube Digital Computer (1946-1958)

In terms of hardware, the logic components use vacuum tubes, and the main memory uses mercury delay lines and cathodes. Ray oscilloscope tube electrostatic memory, magnetic drum, magnetic core; external memory uses magnetic tape. The software uses machine language and assembly language. The application fields are mainly military and scientific computing.

The disadvantages are large size, high power consumption and poor reliability. The speed is slow (generally thousands to tens of thousands of times per second) and expensive, but it lays the foundation for future computer development.

2nd Generation: Transistor Digital Computer (1958-1964)

Software operating systems, high-level languages ​​and their compiler application fields are based on scientific computing and transactions Mainly processing, and began to enter the field of industrial control. It is characterized by reduced size, reduced energy consumption, improved reliability, increased computing speed (generally 100,000 operations per second, and can be as high as 3 million operations), and performance that is greatly improved compared to the first generation computers.

3rd Generation: Integrated Circuit Digital Computer (1964-1970)

In terms of hardware, the logic components use medium and small scale integrated circuits (MSI, SSI). Main memory still uses magnetic cores. In terms of software, time-sharing operating systems and structured and large-scale programming methods have emerged. It is characterized by faster speed (generally millions to tens of millions of times per second), reliability has been significantly improved, prices have further dropped, and products have become generalized, serialized and standardized. Application fields began to enter the fields of word processing and graphics and image processing.

4th Generation: Large Scale Integrated Circuit Computer (1970 to present)

In terms of hardware, logic components use large-scale and very large-scale integrated circuits (LSI and VLSI) . In terms of software, database management systems, network management systems and object-oriented languages ​​have emerged. In 1971, the world's first microprocessor was born in Silicon Valley, USA, ushering in a new era of microcomputers. The application fields are gradually moving from scientific computing, transaction management, and process control to the home.

Due to the development of integration technology, semiconductor chips are more integrated. Each chip can accommodate tens of thousands or even millions of transistors, and the arithmetic units and controllers can be concentrated on one chip, thus Microprocessors appeared, and microprocessors and large-scale and very large-scale integrated circuits can be assembled into microcomputers, which are what we often call microcomputers or PCs. Microcomputers are small, cheap, and easy to use, but their functions and computing speed have reached or even exceeded those of large computers in the past. On the other hand, various logic chips manufactured by large-scale and ultra-large-scale integrated circuits have been used to create supercomputers that are not very large in size but can operate at a speed of 100 million or even billions of operations. After our country successfully developed the Galaxy I supercomputer that can perform 100 million operations per second in 1983, it also successfully developed the Galaxy II general-purpose parallel supercomputer that can perform one billion operations per second in 1993. This period also produced a new generation of programming languages, database management systems, and network software.

With the changes in physical components and devices, not only the computer host has undergone upgrading, but its external devices are also constantly changing. For example, external memory has developed from the initial cathode ray display tube to magnetic cores and magnetic drums, and later to general-purpose magnetic disks. Nowadays, smaller, larger, and faster compact discs (CD-ROMs) have appeared. ).

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