OS - Basics

What is an Operating System?

An operating system (OS) is system software that manages computer hardware and software resources, and provides common services for computer programs.

Components

• Kernel
• Process Management Module
• Memory(RAM) Management Modules
• File System
• Device Drivers
• User Interface

Goals

• Efficiency
• User Convenience
• Security and Protection
• Multitasking and Parallel Processing
• Reliability and Fault tolerance

Functions

1. Process Management: Creation, Scheduling, and termination of process
2. Memory Management: Allocation of memory to process in need for it, and freeing when no longer required. Implement Virtual memory, for using secondary storage as extended RAM
3. File systems management: Managing files on disk
4. Device Management: Abstract hardware devices, for use with software.
5. Security and Access Control: User authentication and protection against unauthorized entry
6. Networking
7. User Interface

The Kernel

Roles:

1. Process Management
2. Memory Management
3. Filesystems
4. Device Control
5. Networking

Classes of devices:

1. Character devices
2. Block devices
3. Network Interfaces