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Lecture 13

Operating Systems

Introduction to Information Technology

With thanks to Dr. HP Guo

Dr. Ken Tsang 曾镜涛Email: kentsang@uic.edu.hkhttp://www.uic.edu.hk/~kentsang/IT/IT3.htmRoom E408 R9

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Outline Software Basics What is an Operating System History of Operating Systems Booting the Computer Functions of Operating Systems Types of Operating Systems Utility Programs in Windows XP

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The Computer Level Hierarchy

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Software Basics Computer = Hardware + Software Software

Application software Address users' specific needs in the real world word processing, music software, image editing, games,

database programs, inventory control systems, etc.

System software Operating system Device drivers Utilities Programming software tools (compilers, debuggers, etc.)

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Computer System

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Who Creates Computer Software?

Programmers High-level language, easy for humans

C++, Java, etc Low-level language, used by CPU

Machine language Compiler

Translate high-level language into low-level language

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Compilation

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Operating Systems A set of programs containing instructions

that maintain and manage the computer resources, such as CPU, memory and input/output devices

Provide an interface through which the user can interact with the computer

The core of a computer’s system software

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History of Operating Systems Batch processing

Professional operators (humans!) combined decks of cards into batches, or bundles, with the appropriate instructions allowing them to be processed with minimal intervention

A program called a resident monitor allowed programs to be processed without human interaction

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History of Operating Systems Resident Monitors

Monitors were the precursors of modern day operating systems

The monitor started the job, gave control of the computer to the job, and when the job was done, the monitor resumed control of the machine

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Spooling Increases in CPU performance made

punched card batch processing less efficient Magnetic tape (as buffer) offered one way to

process decks faster SPOOLing

Simultaneous Peripheral Operation Online Allows I/O and CPU computations to occur in

parallel the simplest form of multiprogramming Spooling example: print spooling

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History of Operating Systems Multiprogramming Systems

allow several executing programs to be in memory concurrently

Timesharing system permits many users to share the same

CPU the CPU switches between user

sessions very quickly, giving each user a small slice of processor time

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Evolution of Operating Systems First-generation computers

Hardware: vacuum tubes and relays Human operators

Second-generation Computers Hardware: transistors Batch processing was introduced as

a means to keep the CPU busy Monitors helped with the processing spooling

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Third-generation computers Hardware: integrated circuits timesharing

Fourth-generation Computers Hardware: VLSI Today’s multi-task, multi-user

operating systems

Evolution of Operating Systems

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Functions of an Operating System?

monitor performance

provide a user interface

provide file management and other utilities

establish an Internet connection

control a network

administer security

start the computer manage programs

schedule jobs and configure devices

manage memory

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Start the Computer What is booting?

Cold boot Turning on computer that has been powered off

Warm boot Restarting computer that is powered on

Process of starting or restarting a computer

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Dual-Boot Dual-Boot permits two or more

operating systems to be installed on one computer

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How does a personal computer boot up?

Step 1. Power supply sends signal to components in system unit

Step 4. Results of POST are compared with data in CMOS chip

Step 2. Processor accesses BIOS to start computer

Step 3. BIOS runs tests, called the POST, to check components such as mouse, keyboard, and adapter cards

Step 5. BIOS looks for system files in floppy disk drive or CD/DVD drive, and then hard disk

Step 6. Kernel (core) of operating system loads into RAM

Step 7. Operating system loads configuration information and displays desktop on screen

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User Interface What is a user interface?

command-line interfacemenu-driven interface

Controls how you enter data and instructions and how information displays on screen

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GUI Graphical User Interface

User interacts with menus and visual images such as icons and buttons

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File System Hierarchical Directories

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Windows File naming Four parts

Drive Path File name File type (extension)

C:\Windows\System\WinTrust.hlp

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Single User / Multitasking

Foreground contains program you are using

Background contains programs that are running but are not in use

Working on two or more programs that reside in memory at same time

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Memory Management Optimizing use of random access memory (RAM) With virtual memory (VM), portion of hard disk is

allocated to function as RAM This process is called paging When an OS spends much of its time paging, instead

of executing application software, it is said to be thrashing

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Scheduling Job

Transferring items Transferring items between storage between storage

and memoryand memory

Sending Sending information information

to output deviceto output device

Processing Processing instructionsinstructions

Receiving data Receiving data from input devicefrom input device

Adjusts schedule based on job’s priority

A A jobjob is operation is operation the processor managesthe processor manages

Jobs

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Spooling Sending print jobs to buffer instead of

directly to printer Print jobs line up in queue Addresses the “slow-I/O vs fast-CPU”

problem

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Device Driver

Device Device DriverDriver

Program that Program that tells operating system tells operating system how to communicate how to communicate

with devicewith device

With With Plug and PlayPlug and Play, , operating system operating system

automatically configures automatically configures new devices as you install new devices as you install

themthem Also called Also called driverdriver

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Types of Operating System Stand-Alone Operating Systems

works on a desktop computer, notebook computer, or mobile computing device

Network Operating Systems designed specifically to support a network

Embedded Operating Systems Found on most mobile computers, PDAs,

and other small devices

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DOS (Disk Operating System)

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Developed in early 1980s for personal computers

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Used command-line interface when first

developed, later included menusSHardly used today

because it does not offer GUI

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DOS: Dirty Operating System

Tim Paterson

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Windows

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More Windows

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And More Windows

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Coming soon: Windows Vista (Longhorn)

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Windows FamilyWindows Version Year Released

Windows 3.x 1990

Windows NT 3.1 1993

Windows 95 1995

Windows NT Workstation 4.0 1996

Windows 98 1998

Windows Millennium Edition 2000

Windows 2000 Professional 2000

Windows XP 2001

Windows XP SP2 2004

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Windows XP Microsoft’s fastest, most reliable Windows

operating system Five editions:

Home Edition, Professional Edition, Tablet PC Edition,Media Center Edition,and 64-bit Edition

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Mac OS X Available only for computers manufactured

by Apple

Macintosh operating system has been model for most GUIs

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UNIX Used by power users because of its

flexibility and power Most versions

offer GUI Both a stand-alone

and a network operating system

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Unix: 1969

Dennis Ritchie

Ken Thompson

Father of C

Turing Award

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Dennis:A Professional Truck Driver

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Ken: A Chess PlayerBelle: ACM chess tournament Championship in 80, 81, 82, 86

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BSD Unix: 1977'It's very simple – you read the protocol and write the code.'"

• BSD Unix

• vi

• BSD TCP/IP

• Co-founder of Sun

• Sparc Microprocessor

• NFS(Network File System)

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Linux Popular, free, multitasking

UNIX-type operating system Open-source software code is available to

public Both a stand-alone

and a network operating system

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GNU & Linux (1991)

Linus Torvalds Richard Stallman

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Others

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Mac OS

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Network OSNetWareNetWare

Designed for Designed for client/server client/server

networksnetworks

Windows Windows Server 2003Server 2003

Upgrade to Windows Upgrade to Windows 2000 Server2000 Server

UNIX / LinuxUNIX / Linux

Multi-purposeMulti-purposeoperating systemoperating system

SolarisSolaris Version of UNIX Version of UNIX developed by Sun developed by Sun

MicrosystemsMicrosystems

Specifically for Specifically for e-commerce applicationse-commerce applications

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Embedded OS What are two operating systems for PDAs? Windows Mobile for Pocket PC Palm OS for Palm, Visor, and CLIE

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Symbian OS Open-source, multitasking operating system

designed for smart phones Make telephone calls,

save appointments, browse Web, send and receive e-mail and faxes, and more

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Utility Program System software that performs

maintenance-type tasks Also called utility

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Windows ExplorerFile Manager

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System Information

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Windows Registry A central record of all the

settings and information relating to Windows and the software and hardware you have installed on your computer

Use Regedit to change it

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Registry Editor

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Summary Software Basics What is an Operating System History of Operating Systems Booting the Computer Functions of Operating Systems Types of Operating Systems Utility Programs in Windows XP

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The pdf slides and glossary are here:

http://www.uic.edu.hk/~davetowey/teaching/CS/it1010/lectures/13.Operating.Systems.pdf http://www.uic.edu.hk/~davetowey/teaching/CS/it1010/lectures/2x2_13.Operating.Systems.pdf http://www.uic.edu.hk/~davetowey/teaching/CS/it1010/lectures/13.Glossary.pdf