Introduction to operating systems-introduction to a simple computer system

In the operating system, the first chapter is the introduction of the operating system. After drawing a picture of the first chapter, it is found that the introduction is mainly about the computer system. This article introduces the entire computer system.

In the hierarchy,

The most hierarchical and complex software. The operating system is a system software that provides management processor, memory, files, and devices. The functionality of the operating system determines its role: to manage resources, to provide convenient interfaces for users, and to expand hardware.

From the perspective of operating system development, the operating system has gone through the computer operating system, network operating system, distributed operating system, and embedded operating system. Currently, the mainstream operating systems include windows, linux, and unlx. among them, our team is most familiar with Windows and has the most linux applications. For example, the current Android operating system is tailored on the linux kernel. The unlx Operating System is currently the only operating system that can be installed and run on a microcomputer, workstation, or mainframe to a giant computer. From the perspective of hardware development, the batch processing operating system, time-based operating system, and real-time operating system are gradually formed.

To make it easier for users to use computer systems, the operating system provides two types of interfaces. They are: programmer interface and Operator Interface. Among them, the programmer interface refers to a group of system function calls, while the Operator Interface refers to a group of Operation Control commands. The Operation Control Command tells the operating system to control the execution steps of jobs, and the system call refers to the call of subprograms.

In computer software, the operating system is the main concern. In hardware, processors need to be concerned. Because the execution of the program must go through the processor. In assembly languages, we can operate on various registers directly. However, on the operating system platform, user programs cannot directly use certain commands. Therefore, how can we ensure that privileged and non-privileged commands can be correctly used? The two working states in the processor, visual and canonicalized, solve the problem of correct use. The PSW is used to determine whether the command should be executed in the visual state or in the canonicalized state.