Introduction to ICT

Introduction to Information and

Communication Technology

(ICT)

Objectives

1. Describe and differentiate functions of computer hardware

2. Distinguish different type of computer software

3. Explain different type of networks and its configurations

4. Identify data communication hardware, software and its channels

Intro

• A computer is a machine that, under a program’s direction, performs four basic operations: input, processing, output, and storage.

• A program is a list of instructions that tells a computer how perform the four operations.

Desktop– PC, Microcomputer

Notebook– Laptop

Workstation

Personal Digital Assistant– PDA, Handheld, Pocket PC

Types of Computers

How Computers “Think”

• Computers use algorithms to solve a problem.

• Algorithms are step-by-step procedures.

The Information Processing Cycle

• The computer performs the four basic operations (input, processing, output, and storage).

Input Processing Output Storage

Objective 1

• Describe and differentiate functions of computer hardware

– Input device– Processors - CPU– Output device– Storage

Computer System

• A collection of related computer components that are designed to work together.

• A system includes hardware and software.

Hardware Software

Hardware

• Hardware is the computer’s physical components.

• The components include:

– Input devices– Enable users to enter data into the computer for processing.

– Processing circuitry– Components located in the system’s case that transform data into information.

Hardware..

– Output devices– Peripherals that show the results of processing.

– Storage devices– Used to store all the programs and data that the computer uses.

– Communication Devices– Used to move data between computers

Input

• The first operation.

• The computer performs arithmetic or comparison operations on data.

• Electrical impulses representing words, numbers, images, or sounds.

Input• Input is any data entered into the

computer’s memory.

• Types of input include:– Data– Unorganized information (words,

numbers, images, or sounds) that the computer converts to meaningful information.

– Software– Programs transferred from storage devices to the computer’s memory.

– Commands– Instructions that tell the computer what to do.

– Responses– Prompts requiring user feedback.

Keyboard

Mouse– pointing device

Microphone–speech-recognition

Digital Cameras

Input Devices

Digital Cameras

Microphone

Touch Screen

Keyboard & Mouse

Wand ReaderStylus Pen

Input Devices: Giving Commands

• Input devices are types of hardware that enable you to get programs, data, commands, and responses into the computer’s memory.

Input: Transforming Data into Information

Command– A type of input that tells the program what to do.

Confirmation– A message that indicates if the command was or was not carried out.

Keyboard– Enables the user to input characters.

Input..

Pointing device– Enables the user to move an on–screen pointer.

Speech-recognition– A program that enables the computer to transcribe spoken words into text.

Processing

• The second operation.

• The computer performs arithmetic or comparison (logical) operations on the data.

• Performed at a very high speed.

Arithmetic

4 + 8 = 12

Logic728 > 546

Motherboard

Central Processing Unit– CPU

Random Access

Memory– RAM

Expansion Card

Processing Devices

Processing: Transforming Data into Information

Central processing unit (CPU)– The computer’s processing circuitry. It is also called a microprocessor.

Chip– A wafer of silicon that contains a complex electronic circuit.

Motherboard– The computer’s main circuit board.

Processing..Memory– Chips that store program

instructions. Random access memory (RAM) is the most important type.

Expansion slots– A receptacle designed to accept a plug-in expansion card.

Expansion card– Used to connect peripherals (input/output devices) to the motherboard.

CPU

• Components:-

Control unit– Coordinates and controls all parts of the computer system.

Arithmetic-Logic unit– Performs arithmetic or logical operations.

Primary storage – Store data from input devices, instructions in computer software and from ALU operation

Control unit

Direct & coordinate the actions of all other components

Primary storage unit (memory)

-Main memory serves as repository where data received, input devices, instructional computer software and arithmetic logic operations are brought together in this unit

Two types of memory :• Random Access memory (RAM)• Read only-memory (ROM)

•RAM• Allows data and instructions to be stored and

retrieved.• Two types: Static RAM & dynamic RAM

ROM

Only allows data & instruction to be retrieved

Two types of ROM:•Programmable read Only Memory(PROM)

Instructions and data entered by users or programmers & cannot be altered. •Erasable Programmable read Only Memory (EPROM)

Instruction and data entered can be altered and re-altered.

Aritmetic Logic Unit

Performs all operation specified by the

control unit to include calculation and

logical operations

Intel Advanced Micro Devices (AMD)

Cyrix Motorola (Apple)

Pentium IV

Pentium MMX

Pentium III

Popular CPUs

Processor capabilities

Depends on:• Processing speed

Measured by cycle time required to execute typical

instruction e.g. million cycles per second (megahertz),

memory capacity.• Memory capacity

- The quantity of data and programs that can be stored in

the primary storage unit.

- Measured by kilobytes or megabytes (MB)

Output

• The third operation.

• The computer shows the results of the processing operation in a way people can understand.

• Data is processed into information.

Output Devices

• Output devices are peripheral devices that enable us to view or hear the computer’s processed data.

• Visual output– Text, graphics, and video.

• Audio output– Sounds, music, and synthesized speech.

MonitorPrinter

Speakers

Output Devices

Output: Displaying the Information

Monitors– Display processing results on a screen.Cathode ray tube– Monitor similar to

televisions.Flat-panel displays (LCD)– Monitor that

uses liquid crystal diodes.

Output..Speakers– Enable the user to hear the

results of sound processing.

Printers– Generate output on paper.Impact printers– Print heads strike a

ribbon to produce an image.

Nonimpact printers– Transfer the image to the paper.

• Inkjet printers• Laser printers

Storage

• The fourth operation.

• The computer saves the data or output so that it can be used again later.

Hard DriveRAM Memory

Memory vs. Storage

• Storage (secondary storage), also known as mass media or auxiliary storage, refers to the various media on which a computer system can store data.

• Storage devices hold programs and data in units called files.

• Files are stored in directories or folders.

• Memory is a temporary workplace where the computer transfers the contents of a file while it is being used.

Why is storage necessary?Storage:

• Retains data when the computer is turned off.

• Is cheaper than memory.

• Plays an important role during startup.

• Plays an input role when starting applications.

• Is needed for output.

• Devices can hold a large amount of data.

Storage Devices

Storage devices are:

• Hardware that is capable of retaining data when the electricity is turned off.

• Able to read (retrieve) data from a storage medium (disk/tape).

• Able to write (record) data to a storage medium.

Hard Drive

Floppy Disk Drive

Zip Drive

CD / DVD Drive

Jazz Drive

Tape Drive

Micro Drive

Storage Devices

Storage: Holding Programs and Data for Future Use

Storage media– Includes all types of storage media.Magnetic storage media– Uses

magnetically sensitive material.Optical storage media– Uses a laser

beam to scan pits etched into a disc.

Storage..

Writing– Recording data to a disk.

Reading– Playing back information on a disk.

Floppy disk– Removable storage medium.

CD ROM– Optical storage medium.

Types of Storage Technologies

• Sequential– Hardware that reads and writes data in a serial (one after the other) fashion.

• Random-Access– Hardware that reads and writes data without going through a sequence of locations.

• Magnetic– Hardware that uses disks or tapes that are coated with magnetic material.

• Optical– Hardware that uses laser beams to read data from plastic disks.

• Solid State– Devices that use nonvolatile memory chips to read and write data.

Tape Backup Unit

Floppy Drive Hard Drive Jaz Drive Zip Drive

Sequential – Magnetic Storage

Random-Access – Magnetic Storage

CD-ROM / DVD Drive

Magneto-Optic (MO) Drive

Sequential – Optical Storage

Magnetic – Optical Storage

Compact Flash MemoryFlash

Memory

Smart Card

Micro Drive

Memory

Stick

PC Card

Solid State Storage

Magnetic tapes

- Stored on reels or cartridge- Sequential access to the data stored- Usually used to backup data

Advantages:

1)     Huge storage capacity

2)     Fast transfer rate

3)     Relatively low cost compared to magnetic dicks

4)     High reliability

5)     Reusability

6)     Portability

Secondary storage devices and media

Magnetic disks

-Most widely used

-Called as “direct access storage devices” because data stored in magnetic disk can be access by computer system and immediately transferred to the primary storage unit.

-Permanent addresses assigned to all locations on a magnetic disk where data is stored

Secondary storage devices and media

Magnetic disks

Advantages:

1)     all as magnetic tapes

2)     direct access

3)  mounting and removing data is not needed

Disadvantages:

1)     more expensive

2)     less portable

3)   data are often loss through destructive read- in.

Secondary storage devices and media

Secondary storage devices and mediaOptical disks

-it has transparent, rigid optical reading devices.

-also known as laser disk

-usually can be read and retrieved but can’t be erased or modified. WORM-write once read many

-can store more data at a lower cost compared to magnetic disk

-disadvantage -slow retrieval.

-e.g. CD-ROM (400 to 600 MB of data)

Objective 2

• Distinguish different type of computer software

– Computer Language– System Software– Application Software

Programming language historyFirst generation- Machine language (0 and 1 )- Unique to a specific computer- Employs binary code - Slow tedious and error-prone. Second Generation-Symbolic (assembly) language -Utilize mnemonics codes and symbolic codes-Faster & fewer errors-e.g. ADD instruction – to add numbers

Programming language historyThird generation- Procedure-oriented languages or compiler Languages- Compilers needed to translate programs written in the languages into machine language program- Enables instructions to be expressed by algebraic or English-like statement- Simpler to learn and easier to use- Less efficient and slower compared to assembly language - e.g BASIC, FOTRAN, PASCAL & C

Programming language history

Fourth Generation- Problem oriented language- User friendly-even users with little previous computer knowledge can use- User just focus on “what” not “how” - Requires shorter time and cost and less error - e.g Structured query language (SQL), Excel, Lotus 

Software

• Software consists of the programs that give the computer’s hardware its step-by-step instructions.

• Software is created by programmers using a programming language.

Software..

• Programs contain units called files.

• Transferring a program into the computer’s memory is called loading.

• Once loaded into memory the program’s instructions are carried out or executed.

Application software

Types of Software

• System software– All programs that help the computer function properly.

• Application software– All the programs you use to perform a task such as writing a letter or browsing the World Wide Web.

System software

• System software is divided into two categories:The operating system:

Provides support for running application software.

Coordinates the various functions of the computer’s hardware.

System utilities:Are programs for optimizing computer

performance.

System Software

Types of Operating Systems

• Command-line interface– Users type instructions at the keyboard, one line at a time. Examples: MS-DOS, PC DOS, UNIX

• Graphical user interface (GUI)– Users choose items from menus by using a pointing device to click on icons which represent resources and commands. Examples: Windows, Mac OS

Command-Line Interface

Graphical User Interface (GUI)

Application Software

• Application software includes all programs that enable us to use the computer in a useful way.

• Custom software is developed for specific needs.

• Packaged software is produced for the mass market.

Software Suite

• A collection of full-featured standalone programs that usually share a common command structure and have similar interfaces.

MS WORD MS EXCEL MS POWERPOINT

MS ACCESS MS FRONT PAGE

Explain different type of networks and its configurations

• Types– LAN, WAN, VAN– Internet, Intranet, Extranet

• Configuration– Star, Ring, Bus, Client/Serve– Centralized vs Distributed

Objective 3

Data communication - Network

Service area

Local Area Network (LAN)Wide Area Network (WAN)

Network Topology

Star TopologyRing TopologyBus TopologyClient server topology

Architecture

Centralized networkDistributed network

NETWORK

Computer Networks

• A computer network consists of two or more computers linked together to exchange data and share resources.

Types of Computer Networks

•LAN

•WAN

•VAN

Links computers within a building or group of buildings

• Uses direct cables, radio, or infrared signals

Local area network (LAN)

File Server

LAN

LAN

Node

Node

Node

Node

Print Server

Files

Printer

Wide Area Network• Links computers separated by a few

miles or thousands of miles

• Uses long-distance transmission media

• typically requires the use of:– gateways to connect different types of

LANs– bridges to connect same-type LANs

• WANs may use common carrier facilities, such as telephone lines, or they may use a Value Added Network (VAN).

LANLAN

Bridge

GatewayGateway

LAN

WAN

WAN

Reduced hardware costs

• Users share equipment

Connected people• People can work

together without being at the same location

• Groupware enables sharing of schedules and communications

Networking Synergies in a Nutshell

Shared applications• Users share software• File server enables all

users to work with the same application program

Building information

resources• Users create common

pools of data that can be accessed by employees

Internet, Intranet, Extranet

The Internet

• A world-spanning computer network.

The Internet• The Internet is a global, interconnected, computer

network in which every computer connected to it can exchange data with any other connected computer.

• It’s the first mass medium that involves computers and uses digitized data.

• It provides the potential for media convergence, the unification of all media.

• It’s transforming how we communicate, obtain information, learn, seek jobs, and maintain professional growth.

• Businesses find it an indispensable tool for their needs.

Electronic mail– (e-mail)

World Wide Web– (WWW)

File Transfer Protocol– (FTP)

Instant messaging

Electronic commerce– (e-commerce)

Internet Services

• Standards and software that make Internet resources, such as Web pages, files, and electronic mail available to users.

Intranets and Extranets

Intra..Extra• Intranet– An internal networking

system within a company.– They function like the Internet.– They are for internal use only and are not

available to those outside the company.• Firewall– Software used to screen

incoming data.• Extranet– An intranet that can be used

by outside sources who access it over the Internet.

Network Configuration

• Topology - Star, Ring, Bus, Client/Server

• Centralized/Decentralized

• Distributed data processing

Star Topology

• A network of IPUs with a large central computer (the host)

• The host computer has direct connections to smaller computers, typically desktop or laptop PCs.

• This topology is popular for mainframe computing.

• All communications must go through the host computer, except for local computing.

Server

Star Topology

Local Files

Local Files

Local Files

Local Files

Local Files

CentralFiles

Ring Topology• This configuration eliminates the

central site. All nodes in this configuration are of equal status (peers).

• Responsibility for managing communications is distributed among the nodes.

• Common resources that are shared by all nodes can be centralized and managed by a file server that is also a node.

Server

Ring Topology

Local Files

Local Files

Local Files

Local Files

Local Files

CentralFiles

Bus Topology

• The nodes are all connected to a common cable - the bus.

• Communications and file transfers between workstations are controlled by a server.

• It is generally less costly to install than a ring topology.

Server

Bus Topology

Node

Node

Node

Node

Local Files

Local FilesLocal Files

Local Files

Local FilesNode

Central Files

Print Server

Client-Server topology• This configuration distributes the

processing between the user’s (client’s) computer and the central file server.

• Both types of computers are part of the network, but each is assigned functions that it best performs.

• This approach reduces data communications traffic, thus reducing queues and increasing response time.

Server

Client-Server Topology

Client

Client

Client

Client

RecordSearchingCapabilities

Data ManipulationCapabilities

ClientData Manipulation

CapabilitiesData ManipulationCapabilities

Data ManipulationCapabilities

Data ManipulationCapabilities

Common Files

Centralized

VS Distributed

Centralized Network• Consists of a single central computer

processor/mainframe that is linked to one or more physically remote terminals and other communication devices

• All application processing done by central computer/mainframe

• Suitable for firms that have centralized organizational structure, homogeneous operations and low processing activities at remote sites.

Centralized NetworkBenefits:- Provide the concentrated computing power of

a large processor which can handle large volume of transactions and complex processing. Such processing can be done at relatively low application costs per transaction-providing economic of scale.

- Large processor can facilitate the use of and integrated databases- reduce data redundancy, simultaneous updating and better data documentation

Centralized NetworkDrawbacks:1. Difficult to design and costly to maintain2. Complicated and costly system software to move

application software in and out of their online library, to assign priorities to message and so on

3. Inflexible and unresponsive to remote users 4. Heavy transmission traffics can cause transaction

and inquiries to be delayed5. Centralized staff may not be attuned to the needs

and circumstances of remote users.6. Vulnerable to disaster-if the central processor fail,

entire network will shut down

Distributed Network• A computer network which processing

task, and possibly also the database management task has been distributed/divided to remote sites.

• User oriented architecture• Distributed network is useful when 1) large volumes of data need to be

processed at remote locations 2) managers or employees need very

fast access to data on a frequent basis

Distributed NetworkBenefits of distributed network:

1)  Responsiveness to user needs

- availability of hardware and software closer to users

- increase the speed of processing and timely report

2)  Optimal use of facilities

- overall processing work load can be shared among

remote processor

- can call help from central processor

3)  Reliability of network operations

- if a particular computer fails, the reminder computers can generally

handle the failed computer’s processing load

- Modularity and simplicity of processing facilities

Distributed NetworkDrawbacks:

1)      adequate controls and security are difficult to maintain

2)      no standardized protocols and equipments-

incompatibility

Identify data communication

• hardware • software and • its channels

Objective 4

Long-distance Transmission Media

Copper wireNamed T1.24 voice calls at a

time.1.544 Mbps of

computer data.

Fiber-optic cableMade of glass

strands.Transmits data using

pulses of light.Named T3.672 voice calls at a

time.43 Mbps of computer

data.

Cont..MicrowaveHigh-frequency radio waves.Travel in a straight line.Relay stations every 30 miles.

SatellitesMicrowave relay stations in space.Positioned in geosynchronous orbits.

Twisted Pair Copper Wire

Fiber Optics

SatellitesMicrowave

Types of Telephone Transmission Media

Multiplexing

• Multiplexing technology enables simultaneous, multi-use of transmission lines.

– Copper wire allows up to 24 simultaneous calls per wire.

– Fiber-optic cables permit up to 43,384 calls per strand.

Internal Modem External Modem

Modems

• Modems are devices that transform signals when sending and receiving transmissions.

• Two types:

– Internal modems– Fit into a computer’s expansion slot.

– External modems– Connect to a port outside the system box.

Asynchronous and Synchronous Communications

• Asynchronous communication is a method of networking where bits of data are sent and received one bit at a time; each byte contains a start and stop bit.

• Synchronous communication requires a synchronization signal which identifies units of data.

Integrated Services Digital Network (ISDN)

• ISDN is a standard that provides digital telephone and data service.

• Types of ISDNs:

– Basic Rate ISDN (BRI)– For home or small businesses; one or two 64 Kbps channels available.

– Primary Rate ISDN (PRI)– Designed for organizations; 23 channels at 64 Kbps available.

– Broadband ISDN (BISDN)– Requires fiber optic-cable; maximum bandwidth of 622 Mbps.

Digital Subscriber Line (DSL)• DSL uses copper wiring, but it is faster than

ISDN; its bandwidth can reach 1.5 Mbps.

• It requires a DSL modem, DSL phone line, and an ISP that provides DSL service.

• Asymmetric Digital Subscriber Line (ADSL) has faster downloading than uploading speeds; downloads at 1.5 Mbps; uploads at 256 Kbps.

Synchronous Optical Network (SONET)

• SONET requires fiber-optic cable to transfer data .

• It provides data transfer rates from 52 Mbps to 1 Gbps.

END