Transcript
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
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