Introduction to Operating Systems

1. Operating Systems Introduction to Operating Systems Prepared by: Dhason

2. Topic & Structure of the lesson • Basic functions of operating systems

3. Learning Outcomes • At the end of this lecture YOU should be able to: • - Discuss the functions of operating systems

4. Introduction • A computer system consists of : • - users, application programs, operating • systems and hardware • An operating system is the layer of software that manages all parts of the hardware and presents an interface that is easier to understand • An operating system shields programmers from hardware complexity

5. Introduction (cont.) • An operating system can be defined as : • - a program that acts as an intermediary • between a computer user and the computer • hardware • - a resource allocator • - a resource manager • - a control program

6. Basic Functions of an Operating System • Accepts commands from the user • Provides desired services to the user and user programs • Act as a system manager / resource manager • - controls hardware and software • - act as an interface between user and system • Manages resources of the computer effectively

7. Services of an Operating System • Services provided to users and programs: • Program Execution – loads a program in memory, runs and terminates the execution either normally or abnormally • Input-Output Operations – control input-output devices • File System Manipulation – allow reading, writing, deletion, creating of files

8. Services of an Operating System (cont.) • Communication – manage shared memory or • message passing for the exchange of • information between processes • Error Detection – take measures to correct errors • to ensure a consistent state

9. Services of an Operating System (cont.) B. Services to ensure efficient operation of the operating system: Resource allocation – CPU scheduling routines for memory, input output devices, file storage to decide the best method to utilize the CPU Accounting – which users are using what kind and how much resources. Usage statistics for performance improvement Protection – user, process and data protection

10. Quick Review Questions 1) State and explain one function of operating systems

11. Question and Answer Session Q & A