The first generation of software (1946- 1953)

The first generation of software is written in machine language, which is an instruction built into the computer circuit and consists of 0 and 1.

Second generation software (1954- 1964)

When the hardware becomes more powerful, more powerful software tools are needed to make the computer use more effectively. Assembly language has taken a big step in the right direction, but programmers still have to remember a lot of assembly instructions.

Third generation software (1965- 1970)

During this period, because transistors are replaced by integrated circuits, the operation speed of the processor is greatly improved, and the processor is in an idle state while waiting for the operator to prepare for the next operation. Therefore, it is necessary to write a program to make all computer resources under the control of the computer. This program is the operating system.

The fourth generation software (197 1- 1989)

In 1970s, structured programming technology appeared. Pascal and Modula-2 languages are formulated by using structured programming rules. Basic, a language designed for the third generation computer, has been upgraded to a structured version. In addition, a flexible and powerful C language appeared.

The fifth generation software (1990- present)

There are three famous events in the fifth generation software: the rise of Microsoft, which dominates the computer software industry, the emergence of object-oriented programming methods, and the popularization of the World Wide Web.

Extended data

According to different licensing methods, software can be roughly divided into several categories:

1, proprietary software:

This authorization usually does not allow users to copy, research, modify or distribute software at will. Violation of this authorization usually entails serious legal responsibility. Traditional commercial software companies will adopt this license, such as Microsoft's Windows and office software. The source code of proprietary software is usually regarded as private property by companies and is strictly protected.

2, free software:

This kind of authorization is just the opposite of proprietary software. It gives users the right to copy, research, modify and distribute the software, and provides the source code for users to use freely, with only a few other restrictions. Linux, Firefox and OpenOffice can all be representatives of this kind of software.

3.* * * Enjoy the software:

You can usually get and use the trial version for free, but there are restrictions on the function or use period. Developers will encourage users to pay for a fully functional commercial version. According to the authorization of the author of * * * software, users can get their copies free of charge from various channels, and can also spread them freely.

4. Free software:

You can get and copy it for free, but you can't modify it without providing the source code.

5, public * * * software:

Software whose original author has given up his rights, whose copyright has expired, or whose author is no longer elegant. There are no restrictions on use.