Chapter 1: Operating System Overview

Chapter 1: Operating System Overview

Concept:An operating system is a system that controls and manages computer hardware and software resources and provides services to users and their applications in the most reasonable and efficient way possible.

Features:

· Concurrency:Enables multiple processes to run at the same time to maximize resource utilization and improve efficiency.

· Sharing

· Virtual

· Uncertainty:Caused by concurrency

Function:

· Process Management

· Storage Management

· File Management

· Device management

Service:

· Public services:

· Command control interface:

Command Line, GUI (graphical user interface), script (interpreted Execution Language, a combination of command lines), NUI (natural user interface)

· System services:

· System call:

Create, open, read, write, close, and delete

Category:

· Network operating systems: resource sharing and strong communication capabilities

· Distributed Operating System

· Parallel Operating System: multiple processor resources can be allocated at the same time

Running environment:

· Kernel mode and user mode:

· The operating system is in the inner state (privileged command)

· The user code is running in the user State (Access Control Command)

· The resources used by the kernel state can be used. The user State can only use limited resources, and the user State can enter the kernel state through system calls or traps.

· Interruptions and exceptions:

· Interrupt Processing asynchronous events

· Exceptions (faults, traps, and suspensions)

· System call

Architecture:

· Integral (Unstructured ):

· Layered:

· Microkernel (customer/Server ):

· Modular (Object-Oriented ):