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1. Introduction to ICT Operating System and Utility Programs Lecture 3

2. Recap Components of a computer Information processing cycle

3. Types of Software Two types of software A pplication software S ystem software Application software consists of programs that perform specific tasks for users, such as a word processing program, e-mail program, or Web browser.  System software  consists of the programs that control the operations of a computer and its devices . It is a layer between user and hardware.

4. System Software System software consists of the programs that control or maintain the operations of the computer and its devices . The two types of system software are operating systems and utility programs .

5. Operating Systems An  operating system  ( OS ) is a set of programs containing instructions that coordinate all the activities among computer hardware devices.

6. Operating Systems An OS can run from optical disk, flash memory, and can be installed on computer’s hard disk and from smart phones ROM. OS varies from computer to computer such as a mainframe does not use an OS designed for personal computers. The OS that a computer uses sometimes called the platform . A cross platform application is one that runs same on multiple OS.

7. Types of Operating System A device-dependent program is one that runs only on a specific type or make of computer or mobile device . Proprietary software is privately owned and limited to a specific vendor or computer or device model . device-independent operating systems that run on computers and mobile devices provided by a variety of manufacturers .

8. Operating Systems

9. Operating System Functions The process of starting or restarting a computer is called booting.

10. Operating System Functions The Kernel is the core of operating system that manages memory and devices, maintains the computer’s clock, starts applications, and assigns the computer’s resources, such as devices , programs, data, and information . The kernel is memory resident.

11. Operating System Functions-Starting

12. Operating System Functions-Starting A boot drive is the drive from which your computer starts. You can boot from a boot disk. A recovery disk contains a few system files that will start the computer.

13. Operating System Functions-Shut Down An operating system includes various shut down options Power off Sleep mode Hibernate

14. Operating System Functions-User Interface A user interface controls how you enter data and instructions and how information is displayed on the screen Graphical User Interface Command Line user interface

15. Graphical User I nterface With a graphical user interface (GUI), you interact with menus and visual images by touching, pointing, tapping , or clicking buttons and other objects to issue commands. Many current GUI operating systems incorporate features similar to those of a browser, such as links and navigation buttons. A graphical user interface designed for touch input sometimes is called a touch user interface . Some operating systems for desktops and laptops and many operating systems for mobile devices have a touch user interface.

16. Graphical User Interface

17. Command Line User Interface In a command-line interface , a user types commands (represented by short keywords or abbreviations) or presses special keys on the keyboard (such as function keys or key combinations) to enter data and instructions. When working with a command-line interface , the set of commands used to control actions is called the command language .

18. Operating System Functions-Managing Programs How an operating system handles programs directly affects your productivity Single user/Single Tasking : allows only one program or app to run at a time Single user/Multi tasking : allows a single user to use two or more programs or apps that reside in memory at the same time . When a computer is running multiple programs concurrently, one program is in the foreground and the others are in the background .

19. Foreground/Background apps

20. Operating System Functions-Managing Programs Pre-emptive Multitasking : operating system interrupts a program that is executing and passes control to another program. A multiuser operating system enables two or more users to run programs simultaneously . A  multiprocessing   operating system can support two or more CPUs running programs at the same time. It can serve as a fault-tolerant computer. Fault-tolerant computer continues to operate when one of its components fails, ensuring no data is lost.