一般而言，现代计算机系统是一个复杂的系统。它是由一个或者多个处理器，主存，硬盘，键盘，鼠标，显示器，打印机，网络接口及其他输入输出设备组成。
     
    操作系统位于计算机系统硬件与应用软件之间，本质也是一个软件。操作系统由操作系统的内核（运行于内核态，管理硬件资源）以及系统调用（运行于用户态，为应用程序员写的应用程序提供系统调用接口）两部分组成。操作系统是当代计算机软件系统的核心，是计算机系统的基础和支撑，它管理和控制着计算机系统中的所有软、硬件资源，可以说操作系统是计算机系统的灵魂。
    
     操作系统课程是计算机专业学生必须学习和掌握的基础课程, 是计算机应用人员深入了解和使用计算机的必备知识, 是进行系统软件开发的理论基础，也是计算机科学与技术专业的一门理论性和实践性并重的核心主干课程。

     本课程的目的是讲解现代计算机操作系统的基本原理、基本设计方法及实现技术，具有分析现行操作系统和设计、开发实际操作系统的基本能力。计算机系统自下而上可以粗略分为四个部分：硬件、操作系统、应用程序、用户。课程系统地介绍了现代操作系统的基本理论和最新技术，并具体分析了Windows和UNIX中的实现技术和方法。首先，课程概述了操作系统的定义、发展、功能、特征和类型； 其次分章节介绍了进程与线程、进程同步与通信、调度与死锁、存储管理、虚拟存储管理、设备管理和文件管理； 在课程中，穿插讲述Windows和UNIX两个常用操作系统的实现技术。每章后附有思考与练习题，并有对应思考与练习题的详细解答。本课程的面向对象是开设操作系统课程的相关专业的本科生，以及具有一些操作系统基本知识并想进一步了解操作系统内部编程的学生。

   学贵有疑，小疑则小进，大疑则大进。疑者，觉悟之机也，一番觉悟一番长进。 在课程的学习过程中，希望各位同学多思考，多提问，学有所获。

In general, modern computer systems are complex systems. It consists of one or more processors, master memory, hard disk, keyboard, mouse, display, printer, network interface and other input and output devices.

The operating system is located between computer system hardware and application software. It is also a software. The operating system consists of two parts: the operating system's kernel(running in the kernel state, managing hardware resources) and the system call(running in the user state, providing the system call interface for the application program written by the application programmer). The operating system is the core of the contemporary computer software system and is the foundation and support of the computer system. It manages and controls all the software and hardware resources in the computer system. It can be said that the operating system is the soul of the computer system.

The operating system course is a basic course that computer students must learn and master. It is a necessary knowledge for computer application personnel to understand and use computers in depth, and it is the theoretical basis for system software development. It is also a core backbone course that pays attention to theory and practice in computer science and technology.
       
The purpose of this course is to explain the basic principles, basic design methods and implementation techniques of modern computer operating systems. It has the basic ability to analyze current operating systems and design and develop actual operating systems. Computer systems can be roughly divided into four parts from the bottom up: hardware, operating systems, applications, and users. The course systematically introduces the basic theories and latest technologies of modern operating systems, and specifically analyzes the implementation techniques and methods in Windows and UNIX. First, the course outlines the definition, development, functionality, features, and types of operating systems; Secondly, the chapter introduces the process and thread, process synchronization and communication, scheduling and deadlock, storage management, virtual storage management, device management and file management; In the course, interspersed with implementation technologies for two commonly used operating systems, Windows and UNIX. Each chapter is followed by reflections and exercises, and there are detailed answers to corresponding reflections and exercises. This course is aimed at undergraduates in related majors who offer operating system courses, as well as students who have some basic knowledge of operating systems and want to learn more about operating system internal programming.
  
There are doubts about the value of learning, but small doubts and big doubts. Suspicion, the opportunity of awakening, a time of awakening and a time of progress. In the course of learning, I hope you can think more, ask more questions and learn more.