What are the three stages and characteristics of software development?

The development of software has roughly gone through the following three stages:

1, the first stage (mid-1940s to mid-1950s).

From the first program on the first computer to the appearance of practical high-level programming language, it is the early stage of computer software development. At present, the field of computer application is relatively narrow, mainly scientific and engineering calculation, the processing object is numerical data, and the program is written in individual way with machine (or assembly) language. In the first stage, as long as we study scientific calculation programs and engineering calculation programs, service programs and libraries, people don't know enough about the importance of program-related documents and pay attention to the program itself.

2. The second stage (mid-1950s to late 1960s).

It is the second stage of software development from the appearance of high-level programming language to the proposal of software engineering. At this stage, the research object has increased concurrent programs, and focused on high-level programming languages, compilers, operating systems and various supporting software and application software. With the strengthening of computer system processing capacity, the working mode of design and programming is gradually moving towards cooperative mode.

3. The third stage (since software engineering was put forward in the late 1960s).

Because the development of large-scale software is an engineering task, it is not only inefficient, unreliable and difficult to complete the task by using a single or cooperative method, but also the need to write software with high efficiency and high quality can be met only by using an engineering method, so the concept of software engineering was put forward at the academic conference organized by the Atlantic Treaty Organization from 65438 to 0968. In the past 40 years, the work in the field of software has presented many new features.

Three stages of software development and their characteristics: programming program, system software, engineering software, reference program and instruction program, document, data programming language assembly and machine language advanced software language software working range programming.