A Course on COMPUTER FUNDAMENTALSmahis.yolasite.com/resources/adm/Introduction.pdf · • A Computer follows a series of instructions that have been programmed into its memory by

1

Company Confidential

1

A Course on

COMPUTER FUNDAMENTALS

Prepared for: *Stars*

New Horizons Certified Professional Course

2

• Overview of Information Processing

• Unit I: Introduction to ComputersClassification of Computer Applications of Computers

• Unit II: Elements of Computer SystemsMemory UnitsInput DevicesOutput Devices

• Unit III: Introduction of Computer SoftwareComputer SecurityComputer Threats & Viruses

CONTENTS

3

Information Processing

• Data & Information

• IT

• Need for IT

• Need for Information

• Qualities for Information

• Generation of Information System(IS)

4

Information Processing

• Data:-

It’s a collection raw facts & figures

• Information:-

Information are the data which have been converted or organised into more useful form.

5

Need for Information

Need for information

• In Business

• In Decision making

In Business

1. As a document

2. As Transaction

3. As Directives

4. As Reports

5. As queries

6

Need for Information

In Decision Making

1. Define the problem

2. Analyze the problem

3. Develop Alternative Solution

4. Select the best solution

5. Convert decision into effective action

7

Qualities for Information

• Availability – information is collected in min. possible time.

• Timeliness – obtained more quickly

• Accuracy – Correct

• Completeness – More comprehensive

• Meaningful - Presented in designed way

8

Generation of IS

• Manual System

• Mechanical System

• EDP System

• MIS

• Decision Support Systems (DSS)

9

UNIT-1

• Introduction to Computers• Characteristics of Computers• History/Evolution• Generation Of Computers• Classification of computers• Applications of Computers

Overview

10

• Definition:

• Its an electronic Device that is used for information

Processing.

• A Computer follows a series of instructions that have

been programmed into its memory by the user

• Calculation Machine-It operates on data that is

presented to it by the user.

• A computer system includes a computer, peripheral devices,

and software

Introduction to Computers

11

Basically any computer is supposed to carry out following

functions

1. Accepting the data as input

2. Storing the data and instruction in its memory and retrieving

the same when required

3. Processing the data as per instruction to convert it into useful

information

4. Communicating the information as output.


12

• Memory is an area of a computer that holds data that is waiting to

be processed, stored, or output

• Storage is the area where data can be left on a permanent basis

• Computer output is the result produced by the computer

• An output device displays, prints or transmits the results of

processing


13

Computer

Performs computations and makes logical decisions

Millions / billions times faster than human beings

Computer programs

Sets of instructions for which computer processes

data

Hardware

Physical devices of computer system

Software

Programs that run on computers


14


Capabilities of

Computers

• Huge Data Storage

• Input and Output

• Processing

Characteristics of

Computers

• High Processing Speed

• Accuracy

• Reliability

• Versatility

• Diligence

15

Types of computers

• Analog – Simulate continuous, physical processes by measuring analogous electrical signals

• Digital – Represent data in the form of discrete numbers - Calculators

• Hybrid – Combine features of analog and digital computers

16

• History of Computer is actually history of men’s zeal for achieving the utmost satisfaction

• It is the history of counting, calculating, computing and data processing.

History Of Computers

17

• Before the 1500s, in Europe, calculations were made with an abacus Invented around 500BC, available in many cultures (China, Mesopotamia, Japan, Greece, Rome, etc.)

• In 1642, Blaise Pascal (French mathematician, physicist, philosopher) invented a mechanical calculator called the Pascaline

• In 1671, Gottfried von Leibniz (German mathematician, philosopher) extended the Pascaline to do multiplications, divisions, square roots: the Stepped Reckoner

None of these machines had memory, and they required human intervention at each step


18

• In 1822 Charles Babbage (English

mathematician, philosopher), sometimes

called the “father of computing” built the

Difference Engine

• Machine designed to automate the

computation (tabulation) of polynomial

functions (which are known to be good

approximations of many useful functions)

• Based on the “method of finite

difference”

• Implements some storage

• In 1833 Babbage designed the Analytical

Engine, but he died before he could build it

• It was built after his death, powered by

steam


19

Generations of Computers

Back to Index

Introduction To Computers

20

Generation of Computers

• First Generation (1946-59)

• Second Generation(1957-64)

• Third Generation(1965-70)

• Fourth Generation(1970-90)

• Fifth Generation(1990 till date)


21

Generation 1: Vacuum Tube Computers

Generation 2: Transistor Computers

Generation 3: Integrated Circuits

Generation 4: Microprocessors


22

First

Generation

Second

Gen.

Third

Gen.

Fourth Gen.

Technology Vacuum

Tubes

Transistors Integrated

Circuits

(multiple

transistors)

Microchips

(millions of

transistors)

Size Filled Whole

Buildings

Filled half a

room

Smaller Tiny - Palm

Pilot is as

powerful as

old building

sized

computer


23

The ENIAC (Electronic Numerical Integrator and Computer) was unveiled in 1946: the first all-electronic, general-purpose digital computer

Generation 1 : ENIAC

24

The use of binary

In the 30s Claude Shannon (the father of “information theory”)

had proposed that the use of binary arithmetic and boolean

logic should be used with electronic circuits

The Von-Neumann architecture

CPU Memory

I/OSystem

25

Generation 2: IBM7094

26

Seymour Cray created the Cray Research CorporationCray-1: $8.8 million, 160 million instructions per seconds and 8 Mbytes of memory

Generation 3: Integrated Circuits

27

Improvements to IC technology made it

possible to integrate more and more

transistors in a single chip

SSI (Small Scale Integration): 10-100

MSI (Medium Scale Integration): 100-

1,000

LSI (Large Scale Integration): 1,000-

10,000

VLSI (Very Large Scale Integration):

>10,000

Microprocessors

Generation 4: VLSI

28

29

Classification of Computers

• Micro Computer (upto 12 MB)

• Mini Computer (4 MB – 20 MB)

• Super Mini (20 MB – 80 MB)

• Mainframe Computer (80 MB – 128 MB)

• Super Computers (256 MB onwards)

30

Computer fundamentals

Data Representation in Computers

31

Objectives

• Introduction (Bit, Byte, KB, MB, GB)

• The Decimal Number System

• The Binary Number System

32

Data Representation

• Data is stored in a computer in binary format as a series of 1s and 0s.

• Computers use standardized coding systems (such as ASCII) to determine what character or number is represented by what series of binary digits.

• Data is stored in a series of 8-bit combinations called a byte.

• Every letter, number, punctuation mark, or symbol has its own unique combination of ones and zeros.

33

Data Representation

On

Off

• A bit or binary digit has one of two values, zero or one

• A byte is the smallest addressable unit of memory (8 bits)

• ASCII provides for 256(or 28) characters

ASCII : American Standard Code for Information Interchange

34

Bits and Bytes

• 8 bits = 1 Byte (1 keyboard character)

• 1,024 bytes = 1 Kilobyte (1KB)

• 1,024 K = 1 Megabyte (MB)

• 1,024 MB = 1 Gigabyte (GB)

35

Elements of Computer System

Unit II: Elements of Computer

Processing System

Memory Units

Input Devices

Output Devices Back to Index

36

Learning Objectives

– Identify and discuss the basic components of a Digital Computer.

– Outline the role of the operating system and discuss how operating systems have evolved over time.

– Identify and briefly describe the functions of the two basic kinds of software.

37

Computer System Components

Math calculations

Access, decode,

coordinate

instructions

Hold program

instructions and

data

38

Hardware Components in Action

• Instruction phase

– Step 1: Fetch instruction

– Step 2: Decode instruction

• Execution phase

– Step 3: Execute the instruction

– Step 4: Store the results

39

Execution of an Instruction

40

Processing and Memory Devices

41

Processing Characteristics and

Functions

• Machine cycle time: Time to execute the instruction phase

• Clock speed: – Rate at which electronic pulses are produces.

– Measured in MHz

• Wordlength– Bit (Binary digiT): 0 or 1

– Unit for moving data

– Wordlength: The number of bits a CPU can process in a unit time

– 32-64 bit processors

42

Number of Bytes

43

Types of Memory (1)

• Random access memory (RAM)

– Volatile

– Extended Data Out (EDO) RAM

– Dynamic Ram (DRAM)

– Synchronous DRAM: • Faster transfer speed between memory and processor

44

Types of Memory (2)

Read-only memory (ROM)

– Non-volatile

– Permanent data and instructions from manufacturer

– Types

• PROM: Programmable

• EPROM: Erasable programmable

45

Basic Types of Memory Chips

46

Secondary Storage and Output Devices

47

Secondary Storage Access

Methods

• Sequential access

– Access in the same order it was written

– Ex: Need to access memory location 5. Then, you need to go through 1, 2, 3, and 4 first.

• Direct access

– Directly access the location

– Faster than sequential access

• Sequential access storage devices (SASD)

• Direct access storage devices (DASD)

48

Secondary Storage Devices (1)

• Magnetic tapes: Similar to audio tapes, SASD

• Magnetic discs: Hard disk, DASD

• RAID: Redundant array of independent inexpensive disks– Data stored more than once in one of the disks

– Even if one disk fails, data can still be retrieved

• SAN: Storage area network– Consist of many storage devices

• Optical discs, DASD– CD-ROM

49

Secondary Storage Devices (2)

• Magneto-optical discs

• Digital versatile discs (DVD): Up to 17 GB storage

• Memory cards

– Installed in a slot

– Portable

• Expandable storage: Removable disk cartridges

50

Types of Secondary Storage

51

Hard Disc

52

Storage Area Network

53

Digital Versatile Disc Player

54

Expandable Storage

55

Comparison of Secondary

Storage Devices

56

Input Devices

• Personal computer input devices– Keyboard– Mouse

• Voice-recognition devices– Microphone– Software to convert voice into bits

• Digital computer cameras– Record images and video

• Terminals– Connects to a powerful server for computations

• Scanning devices– Page– Handheld

• Touch-sensitive Screens

57

A PC Equipped with a Computer Camera

58

Output Devices

• Display Monitors

– Cathode Ray Tube (CRT)

– Wide

– Lights up pixels

• Liquid Crystal Displays (LCDs)

– Flat panel

• Printers and Plotters

– Speed measured in pages (page printed per minute)

• Music Devices

– MP3 Players

59

Laser Printer

60

Types of Computer Systems

61

• Unit III: Introduction of Computer Software

Classifying Softwares

Computer Security

62

Overview of Software

63

Overview of Software

• Computer programs: Sequences of instructions

• Documentation: Describe program functions

• Systems software: Coordinate the activities of the hardware

• Computer system platform:– Hardware configuration + systems software

• Application software: Programs that help users with certain tasks

64

Classifying Software

65

Systems Software

66

Operating Systems

• Perform common computer hardware functions

– Ex: Get input from keyboard

• Provide a user interface

– Command-based user interface (ms-dos)

– Graphical-user interface (windows)

• Provide a degree of hardware independence

– Application program interface

• Manage system memory

– Convert logical view to physical view

67

Operating Systems

• Manage processing tasks

– Allocate computer resources

– Multitasking (run more than once application at a time)

– Time-sharing (allow multiple access to a system)

• Provide networking capability

– Enable connection to the Internet

• Control access to system resources

– Authentication

• Manage files

– Access to files

68

Role of the Operating System

69

Application Program Interface

70

Workgroup Operating Systems

• Windows 2000 Server

• Unix

• Netware

• Red Hat Linux

• Mac OS X Server

71

Application Software

72

Sources of Software

73

Proprietary and Off-the-Shelf Software

74

Examples of Personal Productivity Software

75

Word Processing Program

76

Spreadsheet Program

77

Database Program

78

Computer Security

79

Physical Security and in

Computer Security

• There are many potential risks and threats. You can only defend against some of them, but not all.– Examples of risks: some real, some absurd…

• A heavy object falling from the sky as you walk down the street• Someone stealing your bag on the train• Someone entering your apartment when you are not there• Accidentally eating food that contains poison• Harmful bacteria transmitted by air to many people• and many others…

• Main questions:– What specifically do you want to protect against?– Which threats are most realistic and worth defending against?

80

• Locks and Keys– What you have– Used to lock secrets

• Fences– Used to defend boundaries

• But no protection if you are already inside

– Firewalls are computer fences

• Passwords– What you know– Used to prove that you really are who

you say you are

Physical Security and in

Computer Security

81

Level of Protection and Ease of Use

• Stronger protection means more difficult access

– Both for you and for anyone else

– E.g.: a bank vault vs. an old wooden door

vs.

82

Common Types of Physical and

Computer Threats (1/6)

• Spoofing

– Pretending to be someone you are not• E.g.: “Hi, I’m Bob.”, says Alice.

– “On the Internet nobody

knows you're a dog.”

Question: Is this a real threat for the

company’s business?

Answer:

83



• Tampering

– Manipulating objects that do not belong to you

– E.g.: opening and changing letters addressed not to you

– Shredding documents

Question: Is this a real threat for the company’s business?

Answer:

84



• Repudiation

– Refusing to admit what you have done

Question: Is this a real threat for the

company’s business?

Answer:

Which one of you zebras ate my lunch?

85



• Information disclosure

– Stealing a secret

• E.g.: via eavesdropping

– In the physical world we use keys to lock secrets and to protect property


Answer:

86



• Denial of service

– Preventing a business from working with its customers

– E.g.: preventing those who wait to have their turn; picket lines during strikes


Answer:

87



• Elevation of privilege

– Doing something without permission


Answer:

88

Security Principles (1/3)

• Security is as strong as the weakest link (in the chain)– Therefore, security can never be perfect.

• Defense in depth– Using multiple overlapping defenses– E.g.: a fence + a water trap + dogs + security guards

• Keep it simple– Complex things are very hard to analyze, and can lead

to problems.

89


• Minimize attack surface– E.g.: Fewer entry points into the house are easier to

defend.

• Secure by default– E.g.: door locks that lock without a key

• Least privilege– When you are allowed to do only what is absolutely

necessary for the job (but not more)– E.g.: giving someone only the key to your garage, but

not the keys to the house, the office, and the car

90


• Compartmentalize (to contain potential damage)

– E.g.: Submarines have sealed compartments that do not leak water, even if some of them get flooded.

• Minimize the window of vulnerability

– E.g.: not leaving your front door open for too long without watching it

• Be conservative in what you accept (as valid)

– You do not have to take anything that you do not want.

91

Computer Threats/Virus

92

What is a Computer Virus

• A kind of software programs

– produced by unknown people and harmful to the

computers

• Some varieties of these software are the

– Viruses, Worms and Trojan horses

93

What is a Computer Virus

• The term “Virus" is often used in common

– to describe all kinds of malware (malicious software)

94

Damages done by Viruses

• Sometimes display unwanted messages

• Some tend to destroy programs or data

• Clog computer memory and hence sometimes result in

system crashes

• Format hard disks, Damage programs, Delete files

Viruses

95

Damages done by Viruses

• Simply replicate themselves

• Presents text, video, or audio messages making the user

know their presence

96

Virus spreading methods

• A viruses can copy itself and infect a computer

– without permission or knowledge of the user

• attaches itself to other software programs or

data files

97


• Spreads from computer to computer when the host is

taken to the uninfected computer

– over a network such as over the Internet or carrying it on a

removable medium - a floppy disk, CD, or USB drive

98


• Many viruses are existed in the Internet today and new

ones are discovered every day.

– spread via downloaded software and data files, and email

attachments, etc

99


• Some old viruses are installed themselves into

the disk boot sector

– runs when the user boot the computer from the disk

100


• Some viruses spread through instant messaging

– A virus, in an infected machine, may send a web-address-link as

a message to other contacting machines

– Thinking the link is from a friend (a trusted source), the recipient

may sometimes follow the link to the websit.

101

How Viruses are borne

• Unlike biological viruses, computer viruses do not simply

evolve by themselves

– deliberately created by programmers, or by people who use virus

creation software

102


• Viruses are written as

– to attack the products of specific companies,

– to distribute political messages,

– and financial gain from identity theft,

103


• Some virus writers

– consider their creations to be works of art

– See virus writing as a creative hobby

Releasing computer viruses is a crime in most jurisdictions

104

Viruses can avoid detection

• To avoid detection by users, viruses employ different

deception methods

– They do not make themselves to

• change the date of last modified

• increase file sizes

• damage the files

105

Viruses can avoid detection

– They kill the tasks associated with antivirus software

before it can detect them

106

How Antivirus software works?

• Detect using a list of virus signature definitions

– comparing the files stored on fixed or removable drives (hard

drives, floppy drives), against a database of known virus

"signatures".

• Use a heuristic algorithm to find viruses based on common

behaviors

– Examin the content heuristics of the computer's memory (its RAM,

and boot sectors)

107

How Antivirus software works?

• Some anti-virus programs gives you a real time

protection

– Examin files as they are being opened, downloaded, copied,

accessed, and transmitted etc.

• They need regular updates

– in order to gain knowledge about the latest threats

108

Damage prevention & data

recovering

• Take regular backups (including OS) on different media,

unconnected to the system (most of the time)

• Use backups on optical media like CD and DVD (read-

only), as they can no longer be affected by viruses. • `

• Use an OS on a bootable, to start the computer if the

installed OS become unusable.

How to prevent damages caused by viruses?

109

Keep your computer Virus free

• Install reliable anti-virus software

– the most important step you can take towards keeping your computer

clean of viruses.

• Update your anti-virus software regularly

– variations of viruses and new ones can be slipped if your software is

not current.

• Get immediate protection

– Configure your anti-virus software to boot automatically on start-up

and run at all times.

110


• Don't automatically open attachments

– Ensure that you examine and scan email and other attachments

before they run as they might contain viruses.

• Scan all incoming email attachments

– Do not open any email attached files if the subject line is

questionable, unexpected or the source (address) is unknown,

suspicious or untrustworthy.

• Delete chain emails and junk email

– Do not forward or reply to any of them, they clogs up the network

– Some viruses can replicate themselves and spread through email as

a chain

111


• Be careful when downloading files from the Internet

– Ensure that the source is a legitimate and reputable one

– save all downloads to one folder and test them with your own

anti-virus software before use.

• Always scan new files for viruses before you use them

112


• Backup your files on a regular basis.

• If your computer is on a network, make sure you have

security steps in place to prevent unauthorized users

putting files on your computer.

• Take care using USB flash cards, CDs, zip and floppy

disks

– The more computers flash cards, CDs, zip cards and floppies

have been used on, the better the chance of a virus infecting

them – clean them before use.

Documents

A Course on COMPUTER FUNDAMENTALSmahis.yolasite.com/resources/adm/Introduction.pdf · • A Computer follows a series of instructions that have been programmed into its memory by