1, 1 generation: electronic tube digital machine (1946— 1958). In hardware, the logic element is vacuum tube, and the main memory is mercury delay line, cathode ray oscilloscope electrostatic memory, magnetic drum and magnetic core.
External storage uses magnetic tape. The software uses machine language and assembly language. The application fields are mainly military and scientific computing.
2. The second generation: transistor digital computer (1958— 1964)
The application fields of hardware operating system, high-level language and its compiler are mainly scientific calculation and transaction processing, and begin to enter the field of industrial control.
3. The third generation: integrated circuit digital computer (1964-1970)
In terms of hardware, small and medium-sized integrated circuits (MSI, SSI) are used as logic elements, and the magnetic core is still used as main memory. In terms of software, there are time-sharing operating systems and structured and large-scale programming methods.
4. The fourth generation: LSI (1970 to present)
In terms of hardware, logic elements are large-scale and very large-scale integrated circuits (LSI and VLSI). In software, database management system, network management system and object-oriented language have appeared. 197 1 year, the world's first microprocessor was born in silicon valley, which opened a new era of microcomputers. The application fields are gradually moving from scientific calculation, transaction management and process control to family.
Extended data
1, fast operation speed: the internal circuit of the computer can complete various arithmetic operations at high speed and accurately. At present, the operation speed of computer system has reached trillions of times per second, and the microcomputer can reach more than 100 million times per second, which can solve a large number of complex scientific calculation problems.
2. High calculation accuracy: the development of science and technology, especially the development of cutting-edge science and technology, requires very high calculation accuracy. The reason why the missile controlled by computer can accurately hit the intended target is inseparable from the accurate calculation of the computer.
3. Strong logical operation ability: The computer can not only carry out accurate calculation, but also have logical operation function, which can compare and judge information. The computer can save data, programs, intermediate results and final results, and automatically execute the next instruction according to the judgment result for users to call at any time.
4. Large storage capacity: The internal memory of a computer has memory characteristics and can store a large amount of information, including not only various data information, but also programs for processing these data.
5. High degree of automation: Because the computer has the ability of memory and logical judgment, people can put the pre-programmed program group into the computer memory, and under the control of the program, the computer can work continuously and automatically without manual intervention.
6. High cost performance: Almost every household will have a computer, which is becoming more and more popular. In the 2 1 century, computers will surely become one of the indispensable appliances in every family. Computers have developed rapidly, including desktops and notebooks.
Baidu encyclopedia-computer