Learning Objectives

OPERATING SYSTEM

Introduction

• Every desktop computer uses an operating system.
• The operating system forms a platform for other system software and application software
• The most popular operating systems in use today are:
• Windows from Microsoft
• Mac OS from Apple
• UNIX / LINUX

The structure of an operating system

There are three basic elements that make up the major design components of any operating system:

• User interface
• Kernel
• File management system

User interface

• A user interacts with the operating system through the user interface.
• The user interface is the part of the operating system that can be used to issue commands by either typing them at a command prompt or pointing and clicking the mouse on a graphical user interface (GUI).
• Older operating systems integrated the GUI into the kernel but the modern ones have the user interface separating the graphics subsystem from the kernel (like in Linux and Mac OSX).
• Many operating systems allow the user to install or create any user interface they desire.
• The X Window System in conjunction with GNOME or KDE is a commonly found setup on most Unix and Unix derivative systems.
• Graphical user interfaces evolve over time

Kernel

• This is the core of the operating system.
• The kernel is responsible for loading and operating programs or processes, and managing input and output.

Kernel cont.

• Kernel act as a bridge between applications and the actual data processing done at the hardware level

Resources

File management system

• The file management system is what the operating system uses to organize and manage files.
• A file is a collection of data.
• Virtually all of the information that a computer stores is in the form of a file.
• There are many types of files, including program files, data files, and text files.
• The way an operating system organizes information into files is called the file system.
• Most operating systems use a hierarchical file system, which organizes files into directories under a tree structure.
• The beginning of the directory system is called the root directory.