WEEK 1

COURSE INTRODUCTIONINTRODUCTION TO OPERATING SYSTEMS

OPERATING SYSTEM STRUCTURES

Operating SystemsCS3013 / CS502

Agenda

Course Introduction

Introduction to Operating System

Operating System Concepts

Operating System Structures

2

Course Information

Website http://nile.wpi.edu/~clee01/teaching/cs3013/

6:00-9:50pm class on Mondays 7 weeks for CS3013, 10 weeks for CS502

Office Hours TBD

Textbook Silberschatz, Galvin, and Gagne, Operating Systems

Concepts, Seventh Edition, John Wiley and Sons, 2005.

3

Why an Operating Systems Course?4

WPI CS requirement “Core area” for both undergrads and grads

Understanding of inner workings of “systems”

Combines CS concepts Algorithms, languages, data structures, hardware System design with tradeoffs

Better use of the computer

Prerequisites5

C/C++ Programming

Data Structures

Computer Organization

Unix/Linux user experience and access

Homework, Projects and Exams6

Homework Designed to get you ready for exam Review ideas taught in class

Projects 2 for CS3013 and 3 for CS502 Implementation in Unix environment

Exams 2 for CS3013 and 3 for CS502 Closed book, Closed notes

Grading7

Grading Homework – 10% Projects – 30% Exams – 60%

WPI Academic Honesty Policy http://www.wpi.edu/Pubs/Policies/Honesty/policy.html

Late Policy – 25% per day Contact Professor for extenuating circumstances

8

Questions?

Professor Background

Choong-Soo Lee PhD Candidate in Computer Science Department

Interest in Systems Area Operating Systems Network Performance Multimedia Performance

9

Student Background

Basic Information Name Class (freshman, sophomore, …) Major (CS, EE, …)

C ExperienceCS Courses TakenLinux ExperienceOperating System(s)

10

Agenda11

Objectives12

Identify operating systems

Explain the major OS issues

Describe the history of OS

Explain OS concepts

Identify services provided by OS

Describe different types of OS structures

Class Discussion13

What operating systems do you know?

What is an operating system?

What do you like/dislike about OS(es) you know?

Components of a Computer System14

Program Interface

User Programs

OS Interface

Operating System

Humans

Hardware Interface/Privileged Instructions

CPU/Memory/Disk/etc

Functions of Operating System15

Beautification Principle Hide the details of the physical machine and provide a

more pleasant virtual machine

Resource Principle Allocate resources to processes

Major OS Issues16

OS History17

Single program execution No OS Assembly or lower level language

Batch (Spooling) Introduced notion of interrupts

Multiprogramming Illusion of executing several programs simultaneously Introduced notion of process

Distributed and Network Operating SystemsSpecialized Operating Systems

OS History - Unix and Linux18

Unix Descendant of MULTICS First “C” version in 1973 Posix (1981) defines standard Unix system calls

Linux Open Source 1991, v.01 by Linus Torvalds for 80386 processor

Proper Unix process support

OS History – Linux19

1994, v1.0 Enhanced file system More devices, dynamic kernel modules

1995, v1.2 More hardware support

1996, v2.0 Multiple architectures, multiple processors Threads, memory management

Today, v2.6 0.64% by Net Applications 5.2 million source lines of code (according to

wikipedia)

OS History - Windows20

1988, v1 Win32 API

1990, v3.1 Server and Workstation versions

1996, v4 (Windows 95) Win95 Interface Graphics to Kernel

OS History - Windows21

2000, v5 (Windows 2000) Micro-kernel Multi-user (with terminal services) 4 versions

2005, Windows XP 4 versions: Home, Professional, Media Center, Tablet

2007, Windows Vista 5 versions: Ultimate, Home Premium, Home Basic,

Business, Enterprise

2009?, Windows 7

OS History - Windows22

Today 91.65% by Net Applications Aiming at robust, server market Intel x86 only Lines of code (according to wikipedia)

Windows NT 4.0 : 11-12 million Windows 2000 : more than 29 million Windows XP : 40 million Windows Vista Beta 2 : 50 million

Objectives23

Identify operating systems

Explain the major OS issues

Describe the history of OS

Explain OS concepts

Identify services provided by OS

Describe different types of OS structures

Agenda24

Operating System Concepts25

Processes

Memory Management

Input/Output

Files

System Calls

Process26

Program vs. Process Program : a set of data and code that manipulate it Process : a program in execution

States of a Process Running, Waiting, Ready, etc.

Process “Tree”

Memory Management27

One chunk of physical memory

Shared by all processes

32 bit architecture 232 bytes 4GB

Process 1

Process 2

Process 3Process 4

???

Input/Output28

OS manages resources including other devices

Significant fraction of codeWant to be simple to use

System Bus

CPUDisk

ControllerPrinter

ControllerMemory

Files29

Store data on diskDirectory “Tree”Working DirectoryProtection bitsAbstraction of I/O devicePipe

root

cs1101cs1101

classes jobs

microsoft cisco

System Calls30

Way processes communicate with OS

OS specific

POSIX (1980s) Portable Operating System Interface

Shells31

User’s interface to OS

Simple commands “cd”, “cat”, “top”

Modifiers ‘&’, ‘|’, ‘>’

Agenda32

Services Provided by OS33

User InterfaceProgram ExecutionI/O OperationsFile-system ManipulationCommunicationsError DetectionResource AllocationAccountingProtection and Security

User Interface34

Command Interpreter Included in the kernel, or

External Program Shells

bash, csh, tcsh, etc.

Provides some basic functionality

User Interface35

Graphical User Interface 1970s, Xerox PARC Research Facility

1980s, Popular by Apple Macintosh

Windows 1.0

Unix Desktop Environments

User Interface36

Graphical User Interface

Simple Systems37

Started small and grew, no hardware supportExample

MS-DOS, Embedded Systems

MS-DOS Drivers

ROM - BIOS Device Drivers

Resident System Programming

Application Programming

Simple Systems38

Example Linux

With Modules

Terminal Device Memory

Abstract layersCan only talk to lower layers

Layer NUser interface

.

.

.

Layer 1

Layered Systems39

Layer 0 Hardwar

e

Microkernel40

Minimal Functions in MicrokernelProvide communication facility between

applications and servicesExample

Mach Tru64 Unix, QNX

Kernel

User Process File ServerMemory Server

Virtual Machine41

Abstract the hardware of a single computer into several different execution environments

Example: IBM VM/370 VMWare

Hardware

Virtual Machine

Operating System Operating System Operating System

ProcessProcessProcess

Virtual Machine42

Example Java Virtual Machine

Hardware

Operating System

Java VM Process Process

Java OS

Java Program

Objectives43

Identify operating systems

Explain the major OS issues

Describe the history of OS

Explain OS concepts

Identify services provided by OS

Describe different types of OS structures