01-linux basics - operating system learning
1. Introduction to the operating system
1. Computer Principles
Most modern computers are based on the von Neumann structure. The core idea of this structure is to store the program and data in the computer, execute the first instruction of the program according to the first address of the stored program in the memory, and then process the data. calculate.
A computer should include five basic components: arithmetic unit, controller, storage, input and output devices.
The computer uses binary to represent instructions and data, puts the written program into the memory, and then starts the computer to work, without the intervention of the operator, it can automatically take out the instructions one by one and execute the instructions.
A computer is made up of software and hardware. The hardware is mainly composed of CPU, storage devices, and input and output devices. Software includes operating system, system software and application software.
2. What is the operating system
Operating system, English is operating system (referred to as OS). Wikipedia defines it as:
a group of interrelated system software programs that manage and control computer operations, use and run hardware and software resources, and provide public services to organize user interactions.
Simply put, an operating system is a program, slightly different from the ones we usually use, that helps us coordinate, manage, and control computer hardware and software.
A computer without an operating system is called "bare metal." The operating system runs on the bare metal, and any other software can only run with the support of the operating system.
The reason for the existence of the operating system is to make programming easier. If there is no operating system, a programmer who writes an application program needs to first write a program that can control computer hardware, and then write an application program based on this program. To write a program that controls computer hardware, one needs to understand the computer hardware. The working principle, and then call the corresponding instruction set to control it.
3. Classification of operating systems
Since the development of the operating system, there are many types, which can be divided according to different fields of application:
desktop operating system, server operating system, embedded operating system, mobile device operating system
3.1 Desktop Operating System
Usually the so-called desktop refers to the graphical operation page. Before the desktop operating system was born, the most famous operating system was DOS, but the operation interface of DOS was very unfriendly, it was just code. For this reason, Microsoft launched their first graphical interface operating system-windows 1.0, although There are only 256 colors, but it was attractive enough at the time, until today the three-legged situation of mac os, windows, and linux. Plus the current Huawei Hongmeng system! ! !
3.2 Embedded Operating System
Embedded system is a kind of "special computer system completely embedded in the controlled device and designed for specific applications", such as μClinux (embedded Linux), WinCE (Microsoft embedded, mobile computing platform), RTOS (embedded real-time operation systems, military aviation) or other operating systems. It is widely used in industry, military, aviation and other fields.
3.3 Server Operating System
Server operating systems generally refer to operating systems installed on large computers, such as Web servers, application servers, and database servers, which are the infrastructure platforms of enterprise IT systems.
Server operating systems are mainly divided into four genres: Unix, Linux, Windows Server and Netware.
3.4．mobile device operating system
Mobile devices are also known as cell phones. The operating system is mainly used on smartphones.
The operating systems currently used on mobile phones mainly include Android (Google), iOS (Apple), Symbian (Nokia), BlackBerry OS (Blackberry), windows mobile (Microsoft), Harmony (Huawei Hongmeng), etc.
