An operating system (OS) is software that manages computer hardware resources and provides common services for computer programs. The OS acts as an intermediary between users and the computer hardware. Modern computers consist of processors, memory, disks, printers, and input/output devices that all need to be managed by the OS. The main functions of an OS include providing a user interface, allowing users to run programs, managing hardware devices, organizing file storage, and allocating processor and memory resources. OSes also provide security, error handling, and accounting services. Common types of OSes include single-user and multi-user systems, as well as single-tasking and multi-tasking OSes. Utilities like backup software, antivirus

1. By…
Robin
singh

2. Defin
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Consis
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Typ
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User
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GUI
User
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CUI
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Contents

3. Operating System
• An Operating System is a program that acts
as an intermediary/interface between a user
of a computer and the computer hardware.
• Managing all these varied components
requires a layer of software – the
Operating System (OS).

4. A modern computer consists of
• One or more processors
• Main memory
• Disks
• Printers
• Various input/output devices.

5. • Control/execute user/application programs.
• Handling Input/output Operations
• Manipulation of file system
• Make the computer system convenient to use.
• Ease the solving of user problems.
• Use the computer hardware in an efficient manner.
• Error detection and handling
• Resource allocation
• Accounting
• Information and Resource protection
Operating System goals Or Service

6. Functions of Operating Systems
• Provide a user interface
• Run programs
• Manage hardware devices
• Organized file storage
• Processor Management
• Storage (Memory) Management
• Information Management
Major Function

7. Part Of Operate System
An Operating System has two part:-
1. Kernel
2. Shell
The kernel is responsible for interacting with hardware
and the shell is responsible for interacting with the user
Shell Command.com
Kernel IOS.SYS MSDOS.SYS
Hardware
User 1 User 2 User 3

8. Types of Operating Systems
 Single user/Single tasking OS
 One user works on the system
 Performs one task at a time
 MS-DOS and Palm OS
 Take up little space on disk
 Run on inexpensive computers
 Single user/Multitasking OS
 User performs many tasks at once
 Most common form of OS
 Windows XP and OS X
 Require expensive computers
 Tend to be complex
 Multi user/Multitasking OS
 Many users connect to one computer
 Each user has a unique session
 UNIX, Linux, and VMS
 Maintenance can be easy
 Requires a powerful computer

9. Types of Operating Systems
 Time Sharing operating system
 Time Shearing technic
 If the time elapses, CPU shift over to the next job waiting & the
previous Program is put to wait
 Interactive OS
 Interactive in nature
 Provide GUI interface
 Easy interaction
 Real-time operating system
 Very fast small OS
 Built into a device
 Respond quickly to user input
 MP3 players, Medical devices

10. Multi user/Multi tasking OS
User 1 User 2

11. Providing a User Interface
• User interface
– How a user interacts with a computer
– Require different skill sets

12. Providing a User Interface
• Graphical user interface (GUI)
– Most common interface
– Windows, OS X, Gnome, KDE
– Uses a mouse to control objects
– Uses a desktop metaphor
– Shortcuts open programs or documents
– Open documents have additional objects
– Task switching
– Dialog boxes allow directed input

13. Graphical User Interface

14. Providing a User Interface
• Command line interfaces
• Or
• Command User Interface
– Older interface
– DOS, Linux, UNIX
– User types commands at a prompt
– User must remember all commands
– Included in all GUIs

15. Command Line Interface
Command User Interface
&

16. Running Programs
• Many different applications supported
• System call
– Provides consistent access to OS features
• Share information between programs
– Copy and paste
– Object Linking and Embedding

17. Managing Hardware
• Programs need to access hardware
• Interrupts
– CPU is stopped
– Hardware device is accessed
• Device drivers control the hardware

18. Organizing Files and Folders
• Organized storage
• Long file names
• Folders can be created and nested
• All storage devices work consistently

19. Enhancing an OSUtilities
– Provide services not included with OS
– Goes beyond the four functions
– Firewall, anti-virus and compression
– Prices vary
 Backup software
 Archives files onto removable media
 Ensures data integrity
 Most OS include a backup package
 Many third party packages exist
 Anti-virus software
 Crucial utility
 Finds, blocks and removes viruses
 Must be updated regularly
 McAfee and Norton Anti-Virus
 Firewall
 Crucial utility
 Protects your computer from intrude
 Makes computer invisible to hackers
 Zone Labs is a home firewall
 Cisco sells hardware firewalls
 Intrusion detection
 Often part of a firewall package
 Announces attempts to breach security
 Snort is a Linux based package

20. Backup Software

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