The development of system software, the concept of system software

Refers to the system that controls and coordinates computers and peripheral devices, supports the development and operation of application software, and is a collection of various programs without user intervention.

The main function is to schedule, monitor and maintain the computer system; Responsible for managing the various independent pieces of hardware in a computer system so that they can work in harmony.

The main characteristics of the system software are: it has strong interaction with the computer hardware system, can schedule and manage shared resources, and can solve the coordination problems in the processing of concurrent operations.

The types of system software are as follows:

1. Operating system.

The operating system is the underlying system software, which is the first expansion of the hardware system functions, and is also the basis for other system software and application software to run on the computer.

The operating system provides an interface between man and machine, and has five management functions: storage management, processor management, device management, file management and process management.

2. Language processing programs.

In order for people to use computers to solve practical problems, they must first write programs. A programming language is a language used to write programs, and it is a channel for exchanging information between humans and computers.

The programming language is an important part of the software system, and the corresponding various language processing programs belong to the system software. Programming languages generally divide into three categories: machine language, assembly language, and high-level language.

3. Database management system.

With the development of computer applications in information processing, information retrieval and various management systems, it is required to process a large amount of certain data, establish and retrieve a large number of **. If these data and ** are organized according to certain rules. It can make these data and ** more processed and retrieved more quickly, and more convenient for users to use, so the database appeared.

4. Service procedures.

Service programs include programs, computer hardware initialization programs, and test troubleshooting programs, which are mainly used for application services of computer equipment itself. For example, memory checking, optimization management, disk formatting, error checking, disc writing, network connection, etc. are all part of the service program. <>

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

1. The first stage (mid-40s to mid-50s of the 20th century).

From the first program on the first computer to the advent of practical high-level programming languages, it was the early days of computer software development. At this stage, the field of computer application is relatively narrow, mainly scientific and engineering computing, the object of processing is numerical data, and the program is written in machine (or assembly) language in an individual way. In the first stage, as long as scientific computing programs and engineering calculation programs, service programs and program libraries are studied, the importance of program-related documents is not well understood, and the focus is on the program itself.

2. The second stage (mid-50s to late 60s of the 20th century).

From the advent of high-level programming languages to the introduction of software engineering, it was the second stage of software development. At this stage, the research object is increased to concurrent programs, and the research focuses on high-level programming languages, compilers, operating systems, and various supporting and application software. As the ability of computer systems to process chanting and meditation has been strengthened, the way of working in designing and programming has gradually moved towards a cooperative approach.

3. The third stage (since the software engineering was proposed in the late 60s of the 20th century).

Because the development of large-scale software is an engineering task, the use of individual or cooperative methods is not only inefficient, poor reliability, and difficult to complete the task, only the use of engineering methods can meet the needs of high-efficiency and high-quality software preparation, so in 1968 in the Onishi Masui Convention organization of the academic conference proposed the concept of software engineering. Over the past 40 years, work in the field of software has taken on many new features.

The three periods of software development and their characteristics: programming programs, system software, engineering software, referred to program programs and manuals, documents, data, programming language assembly and machine language high-level language software language scope of work programming.