Most operating systems support the following types of system components:

Process Management

Main-Memory Management

I/O System Management

File Management

Protection System

Networking (Distributed Systems)

Command-Interpreter System

Operating-System Services

Additional operating-system functions exist not for helping the user, but rather for ensuring efficient system operation.

System Calls

System Programs

System Structure - Simple Approach

System Structure - Layered Approach

Virtual Machines

Advantages and Disadvantages of Virtual Machines

System Design Goals

Mechanisms and Policies

System Implementation