Transcript Operating Systems

Introduction to Information Technology
Lecture 13
Operating Systems
Dr. Ken Tsang 曾镜涛
Email: [email protected]
http://www.uic.edu.hk/~kentsang/IT/IT3.htm
Room E408 R9
With thanks to Dr. HP Guo
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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
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Computer = Hardware + Software
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Software
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Application software
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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
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Device drivers
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Utilities
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Programming software tools (compilers, debuggers, etc.)
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Computer System
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Who Creates Computer
Software?
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Programmers
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High-level language, easy for humans
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Low-level language, used by CPU
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
C++, Java, etc
Machine language
Compiler
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Translate high-level language into lowlevel language
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Compilation
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Operating Systems
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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
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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
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
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

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Increases in CPU performance made punched
card batch processing less efficient
Magnetic tape (as buffer) offered one way to
process decks faster
SPOOLing

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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
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
allow several executing programs to be in
memory concurrently
Timesharing system

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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
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First-generation computers
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Hardware: vacuum tubes and relays
Human operators
Second-generation Computers

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Hardware: transistors
Batch processing was introduced as a
means to keep the CPU busy
Monitors helped with the processing
spooling
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Evolution of Operating Systems
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Third-generation computers

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Hardware: integrated circuits
timesharing
Fourth-generation Computers

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Hardware: VLSI
Today’s multi-task, multi-user operating
systems
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Functions of an Operating System?
start the computer
provide a user interface
manage programs
administer
security
manage
memory
control a
network
provide file
management
and other
utilities
monitor
establish an
performance Internet
connection
schedule jobs
and configure
devices
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Start the Computer


What is booting?
Process of starting or restarting a computer
 Cold boot
Turning on
computer that has
been powered off
 Warm boot
Restarting
computer that is
powered on
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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 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 4. Results of POST
are compared with data in
CMOS chip
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
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desktop on screen
User Interface


What is a user interface?
Controls how you enter data and instructions and how
information displays on screen
command-line interface
menu-driven interface
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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
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Hierarchical Directories
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Windows File naming
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Four parts
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Drive
Path
File name
File type (extension)
C:\Windows\System\WinTrust.hlp
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Single User / Multitasking

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Working on two or
more programs that
reside in memory at
same time
Foreground contains
program you are using
Background contains
programs that are
running but are not in
use
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Memory Management
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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
Jobs
Adjusts schedule
based on
job’s priority
A job is operation
the processor manages
Receiving data
from input device
Sending
information
to output device
Processing
instructions
Transferring items
between storage
and memory
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Spooling
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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
Program that
tells operating system
how to communicate
with device
Also called driver
Device
Driver
With Plug and Play,
operating system
automatically configures
new devices as you install
them
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Types of Operating System
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Stand-Alone Operating Systems
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
Network Operating Systems
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works on a desktop computer, notebook
computer, or mobile computing device
designed specifically to support a network
Embedded Operating Systems
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Found on most mobile computers, PDAs, and
other small devices
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DOS (Disk Operating System)
Developed in
early 1980s
for personal
computers
Hardly used today
because it does
not offer GUI
D Used command-line
O
S
interface when first
developed, later
included menus
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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 Family
Windows 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

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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
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Available only for computers manufactured by
Apple
Macintosh operating
system has been
model for most GUIs
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UNIX
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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
Ken Thompson
Dennis Ritchie
Father of C
Turing Award
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Dennis:
A Professional Truck Driver
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Ken: A Chess Player
Belle: 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

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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)
Richard Stallman
Linus Torvalds
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Others
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Mac OS
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Network OS
NetWare
Designed for
client/server
networks
Windows
Server 2003
UNIX / Linux
Upgrade to Windows
2000 Server
Multi-purpose
operating system
Solaris
 Version of UNIX
developed by Sun
Microsystems
 Specifically for
e-commerce applications
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Embedded OS
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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

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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 Explorer
File 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.Sys
tems.pdf
http://www.uic.edu.hk/~davetowey/teaching
/CS/it1010/lectures/13.Glossary.pdf
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