Operating system and its functions

The goal of lecture
Examine the purpose and functions of operating systems.

Lesson plan
Architecture of Computer System
Operating System and its Functions
Common Operating Systems and Their Differences

Main terms of lesson

Architecture of Computer System

-An Operating system(OS) is a program that manages the computer hardware.
-It also provides a basis for Application Programs and acts as an intermediary between computer User and computer Hardware

System Software, Application Software and Driver Programs
System Software- Performs essential operation tasks
Operating system
Utility programs
Application Software - Performs specific tasks for users
Business application
Communications application
Multimedia application
Entertainment and educational software
Driver Programs (Device Driver)
small program that allows a specific input or output device to communicate with the rest of the computer system

3 type of programs
user / application programs
programs used by the users to perform a task
system programs
an interface between user and computer
driver programs
communicate I/O devices with computer

Operating System
a collection of programs which control the resources of a computer system
written in low-level languages (i.e. machine-dependent)
an interface between the users and the hardware
when the computer is on, OS will first load into the main memory

Operating
System
Device configuration
Controls peripheral devices connected
to the computer
File management
Transfers files between main memory and secondary storage, manages file folders, allocates the secondary storage space, and provides file protection and recovery
Memory management
Allocates the use of random access memory (RAM) to requesting processes
Interface platform
Allows the computer to run other applications
Basic functions of the operating system

Functions of Operating system
Process Management
Memory Management
File Management
Security management
Command Interpreter

1.Process management
By process management OS manages many kinds of activities :-
All process from start to shut down
Creation and deletion of user and system processes.

2. Memory Management
The major activities of an operating regard to memory-management are:-
Decide which process are loaded into memory when memory space becomes available.
Allocate and deallocate memory space as needed.

3.File Management
The file management system allows the user to perform such tasks:-
Creating files and directories
Renaming files
Coping and moving files
Deleting files

4.Security Management
By security management OS manages many tasks such as:-
Alert messages
Dialogue boxes
Firewall
Passwords

5.Command Interpreter
A command interpreter is an interface between system and the user. There are two types of user interface:-
Command line
Graphical user interface

Contd……
With a command line user interface the user interact with the OS by typing command to perform specific tasks
With a graphical user interface the user interacts with the OS by using a mouse to access windows icons and menus

Other function of Operating System
best use of the computer resources
provide a background for user’s programs to execute
display and deal with errors when it happens
control the selection and operation of the peripherals
act as a communication link between users
system protection

Common Operating Systems and Their Differences
Network Operating System
UNIX / Linux / MS Windows2000 Server
Desktop Operating System
MS Windows 9X/Me / Mac OS / DOS
Mobile Operating System
Palm OS and Pocket PC

Examples
Common operating systems
WINDOW
used in IBM compatible microcomputers
UNIX
multi-user, multi-tasking OS used in minicomputers and microcomputers
VAX/VMS
used in DEC’s VAX series of minicomputers

DOS interface

Disk Operating System (DOS)
a part of operating system to control disk operation
2 parts
small system data
keep track of key information of the disk
data area
where data file is stored

Different Types of Operating System

Some Examples of Operating System

SIW
Human-computer interaction.
The user interface, as a means of human-computer interaction. Interface Usability.
Types of interfaces: a command line interface, text-based, graphical user interface.
Physical and mental characteristics of the user. Stages of development of the user interface.