CS703 Handouts

Advance Operating System · Course - Code: CS703 · Chapter · Subject · Lectures Page

Introduction and Basic Concepts 01-03 Process and Threads 04-22 22-28 File Systems 29-34 Input / Output 35-38 Security 39-45

Presented by:

Mr. Farhan Zaidi MS Computer Science University of Southern California, USA

Reference Book 1:

Modern Operating Systems by Tanenbaum

Download Link:

Reference Book 2:

Operating Systems Concepts by Siberschatz, Galvin, Gagne

Download Link: · A World Class Education at Your Door Step · Lecture 1:

Course Objectives and Pre-requisites Introduction to what an operating system is? Issues involved in the design of an operating system Different types of operating systems

Course objectives

In depth treatment of topics from design perspective. Consider why things are done in a certain way instead of just how they are done. Consider design alternatives. Be able to tell the difference between a good design and a bad design. Also consider engineering tradeoffs involved in the design process. Practical aspects from a computer scientist‘s perspective.

These include:

1. A case study throughout the course of a real commercial operating system kernel. We will present Linux kernel for this purpose. We will also make comparisons to other operating systems e.g. Windows where applicable.
2. Hands on training as a programmer on using operating system services in relatively complex programs. I will assign 4 to 5 programming assignments for this purpose.

Research perspective

We will also look at some contemporary and classical research on operating system topics in the research literature. For this purpose, I will assign a few readings from the literature on operating systems.

Course Pre-requisites

C/C++ programming. This is an essential pre-requisite since without this; you won‘t be able to do the assignments. An undergraduate first course on data structures. This should include implementation of elementary data structures e.g. lists, stack, queues, trees etc. in a high level language like C or C++ etc. A first course on operating systems would be helpful but not strictly required since we will cover the basics of each topic before diving into the deeper stuff.

What is an operating system?

Top-down view Provides an extended or virtual machine abstraction to user programs Easier to program than the underlying hardware. All services are invoked and accomplished through system calls. Bottom-up view Acts as a resource manager of a complex system Resources consist of processors, memories, timers, disks, mice, keyboard, network interfaces, printers etc. OS manages allocation of these resources to user programs in an orderly and controlled manner

Resource multiplexing

OS multiplexes resources in two ways: In time, In space Time multiplexing involves different programs taking turns in using the resource. Example: CPU scheduling, printer sharing. Space multiplexing involves different program getting part of the resource possibly at the same time. Example: memory is divided into several running programs.

The major OS issues

Structure: how is the OS organized?

Sharing: how are resources shared across users?

Naming: how are resources named (by users or programs)?

Security: how is the integrity of the OS and its resources ensured?

Protection: how is one user/program protected from another?

Performance: how do we make it all go fast?

Reliability: what happens if something goes wrong (either with hardware or with program)?

Extensibility: can we add new features?

Communication: how do programs exchange information, including across a network?

More OS issues

Concurrency: how are parallel activates (computation and I/O created and controlled? Scale: what happens as demands or resources increase?

Persistence: how do you make data last longer than program executions? Distribution: how do multiple computers interact with each other?

Accounting: how do we keep track of resources usage, and perhaps charge for it?

Protection and security as an example

None OS from my program Your program from my program My program from my program Access by intruding individuals Access by intruding programs Denial of service Distributed denial of service Spoofing Spam Worms Viruses Stuff you download and run knowingly (bugs, Trojan horses) Stuff you download and run unknowingly (cookies, spyware)