When did the fourth generation of computers come out in the last century?

The fourth generation of computers came out in the 1970s, that is, in 1971. The fourth generation of computers is composed of large-scale and very large-scale integrated circuits. It can calculate various large-scale data and help users solve more problems.

The fourth generation computer: large scale integrated circuit computer

The fourth generation electronic computer is characterized by large-scale and ultra-large Scale integrated circuits as basic electronic components.

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. ).

Features

The fourth generation computer refers to the use of large-scale integrated circuits (LSI) and very large-scale integrated circuits (VLSI) as the main electronic devices since 1970. computer. For example, the 80386 microprocessor can integrate approximately 320,000 transistors on a single chip with an area of ​​approximately 10mm × 10mm.

Another important branch of the fourth generation of computers is microprocessors and microcomputers developed based on large-scale and very large-scale integrated circuits.

Four stages

The first stage was from 1971 to 1973, with microprocessors including 4004, 4040 and 8008. In 1971, Intel developed the MCS4 microcomputer (CPU 4040, four-bit computer). Later, the MCS-8 model with 8008 as the core was launched.

The second stage is from 1973 to 1977, the development and improvement stage of microcomputers. Microprocessors include 8080, 8085, M6800, and Z80. The initial product is Intel's MCS-80 (CPU is 8080, eight-bit machine). Later, there were TRS-80 type (CPU is Z80) and APPLE-II type (CPU is 6502), which were once popular in the world in the early 1980s.

The third stage is from 1978 to 1983, the development stage of sixteen-bit microcomputers. Microprocessors include 8086, 8088, 80186, 80286, M68000, and Z8000. The representative product of microcomputer is IBM-PC (CPU is 8086). The pinnacle products of this stage were APPLE's Macintosh (1984) and IBM's PC/AT286 (1986) microcomputers.

The fourth stage is the development stage of 32-bit microcomputers starting in 1983. Microprocessors have successively launched 80386 and 80486. 386 and 486 microcomputers are initial products. In 1993, Intel introduced the Pentium or P5 (Chinese translation as "Pentium") microprocessor, which has a 64-bit internal data channel. The Pentium III (also known as P7) microprocessor has become a mainstream product, and the Pentium IV was launched in October 2000.

It can be seen that the performance of a microcomputer mainly depends on the performance of its core device - the microprocessor (CPU).

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