Introduction to OS & Computer organization © Dr. Aiman Hanna Department of Computer Science Concordia University Montreal, Canada

2 Introduction to OS What is an OS? What is an OS? Software: Software: System software System software Application software Application software

3 Application Software System Software Hardware (a)End User View (b) Application Programmer View (c) OS Programmer View Application Software Application Software System Software System Software Hardware cut save print send malloc() fork() open() read-disk track-mouse start-printer Software/Hardware

4 Different Software/Hardware Interfaces Hardware Resources Trusted OS (Abstract Resources ) Software-Hardware Interface OS Interface System Software (More Abstract Resources ) API Application Software Human-Computer Interface

5 Introduction to OS Different Kinds of OS Different Kinds of OS Batch Batch Timesharing Timesharing Real-time Real-time Dedicated (Embedded) Dedicated (Embedded) Distributed Distributed Mobile Mobile …etc. …etc.

6 Basic Functions of OS Resource Abstraction Resource Abstraction Resource Sharing Resource Sharing Resource Isolation Resource Isolation

7 Advantages of Sharing Multiprogramming Multiprogramming Multitasking Multitasking

8 Computer Organization Von Neumann Architecture Von Neumann Architecture ALU ALU Control Unit Control Unit I/O Devices I/O Devices …. ….

9 Memory Organization IR, MDR, PC, … IR, MDR, PC, … Fetch cycle Fetch cycle Interrupt cycle Interrupt cycle

10 Where is this week coverage in the textbook? Chapter 1: Chapter 1: Sections 1.1, 1.3, 1.4, 1.6, 1.7, 1.8, 1.9, 1.11 & 1.13 Sections 1.1, 1.3, 1.4, 1.6, 1.7, 1.8, 1.9, 1.11 & 1.13  Permanently Skip: Sections 1.10 & 1.12  Note: Parts of these permanently skipped sections will actually be discussed in class and during lab times; however, you can still skip them when reading/studying for the course.