Introduction to ICT

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COMPUTERS IN THE HOME

Computers used for a variety of tasks:Looking up information and newsExchanging e-mailShopping and paying billsWatching TV and videosDownloading music and moviesOrganizing digital photographsPlaying gamesTelecommuting

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COMPUTERS IN THE HOME

ConvergenceThe computer has become the central part of

home entertainmentDual-mode mobile phones

Wireless networkingComputers can be used in nearly any location

Smart appliancesTraditional appliances with built-in computer or

communication technology Smart homes

Household tasks are monitored and controlled by a main computer in the house

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COMPUTERS IN THE HOME

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COMPUTERS IN EDUCATION

Many students today have access to computers either in a classroom or a computer lab

Colleges and universities are even more integratedWireless hotspots allow usage of personal

laptops to connect to the college networkSome colleges require a computer for

attendance Distance learning

Students participate from locations other than the traditional classroom setting using computers and Internet access

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COMPUTERS IN EDUCATION

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COMPUTERS ON THE JOB

Computers have become a universal on-the-job tool for decision-making, productivity, and communicationUsed by all types of employeesUse by service professionals is growingUsed extensively by the militaryEmployees in all lines of work need to

continually refresh their computer skills

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COMPUTERS ON THE JOB

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COMPUTERS ON THE GO

Computers are encountered in nearly every aspect of daily lifeATM transactionsPortable computers or mobile devicesM-commerce systemsGPS systems

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COMPUTERS ON THE GO

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WHAT IS A COMPUTER AND WHAT DOES IT DO?

Computer: A programmable, electronic device that accepts data, performs operations on that data, and stores the data or results as needed Computers follow instructions, called programs,

which determine the tasks the computer will perform

Basic operations Input: Entering data into the computer Processing: Performing operations on the data Output: Presenting the results Storage: Saving data, programs, or output for

future use Communications: Sending or receiving data

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WHAT IS A COMPUTER AND WHAT DOES IT DO?

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DATA VS. INFORMATION

Data Raw, unorganized factsCan be in the form of text, graphics, audio,

or video Information

Data that has been processed into a meaningful form

Information processingConverting data into information

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COMPUTERS THEN AND NOW

The history of computers is often referred to in terms of generations

Each new generation is characterized by a major technological development

Early computers (before 1946)Abacus, slide rule, mechanical

calculatorPunch Card Tabulating Machine

and Sorter

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COMPUTERS THEN AND NOW

First-generation computers (1946-1957) Enormous and powered by vacuum tubes Used a great deal of electricity, and

generated a lot of heat ENIAC and UNIVAC

Second-generation computers (1958-1963) Used transistors Computers were smaller, more powerful,

cheaper, more energy-efficient, and more reliable

Punch cards and magnetic tape were used to input and store data

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COMPUTERS THEN AND NOW

Third-generation computers (1964-1970)Used integrated circuits (ICs)Keyboards and monitors introduced

Fourth-generation computers (1971-present)Use microprocessors IBM PC, Apple MacintoshUse keyboards, mice, monitors, and printersUse magnetic disks, flash memory, and optical

disks for storageComputer networks, wireless technologies,

Internet introduced

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COMPUTERS THEN AND NOW

Fifth-generation (now and the future)May be based on artificial intelligence (AI)Likely use voice and touch inputMay be based on optical computers and

utilize nanotechnology( atomic, Molecular, Super molecular)

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COMPUTERS THEN AND NOW

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HARDWARE

Hardware: The physical parts of a computer Internal hardware

Located inside the main box (system unit) of the computer

External hardware Located outside the system unit Connect to the computer via a wired or wireless

connectionThere is hardware associated with all five

computer operations

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HARDWARE

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HARDWARE

Input devicesUsed to input data into the computerKeyboards, mice, scanners, cameras,

microphones, joysticks, touch pads, touch screens, fingerprint readers, etc.

Processing devicesPerform calculations and control computer’s

operationCentral processing unit (CPU) and memory,

microcontrollers Output devices

Present results to the userMonitors, printers, speakers, projectors, etc.

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HARDWARE

Storage devicesUsed to store data on or access data from

storage mediaHard drives, CD/DVD discs and drives, USB

flash drives, etc. Communications devices

Allow users to communicate with others and to electronically access remote information

Modems, network adapters, etc.

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HARDWARE

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SOFTWARE

Software: The programs or instructions used to tell the computer hardware what to doSystem software: Operating system starts up

the computer and controls its operation Without OS computer cannot function Boots the computer and launches programs at the

user’s direction Most use a GUI to interact with the user via

windows, icons, menus, buttons, etc. Windows, Mac OS, Linux, etc.

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SOFTWARE

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APPLICATION SOFTWARE

Application software: Performs specific tasks or applications Creating letters, budgets, etc. Managing inventory and customer databases Editing photographs Scheduling appointments Viewing Web pages Sending and receiving e-mail Recording / playing CDs/DVDs Designing homes Playing games

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SOFTWARE

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COMPUTER USERS AND PROFESSIONALS

Computer users (end users): People who use a computer to obtain information

Computer professionals include:ProgrammersSystems analystsSecurity specialists

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COMPUTERS TO FIT EVERY NEED

Six basic categories of computers:Embedded computersMobile devicesPersonal computersMidrange serversMainframe computersSupercomputers

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EMBEDDED COMPUTERS

Embedded computer: Embedded into a product and designed to perform specific tasks or functions for that product

Cannot be used as general-purpose computers

Often embedded into:Household appliancesThermostatsSewing machinesCars

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MOBILE DEVICES Mobile device: A very small

device with some type of built-in computing or Internet capability

Typically based on mobile phones

Typically have small screens and keyboards

Examples:Smart phonesHandheld gaming devicesPortable digital media players

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PERSONAL COMPUTERS (PCS)

Personal computer: A small computer designed to be used by one person at a timeAlso called a microcomputerRange in size from desktop computers to

UMPC’sCan use tower case, desktop caseCan be PC-compatible or MacintoshNot designed to be portable

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PORTABLE COMPUTERS

Notebook (laptop) computers Tablet computers: Can

be slate tablets or convertible tablets

Ultra-mobile PCs (UMPCs):Handheld computers

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THIN CLIENTS AND INTERNET APPLIANCES

Thin client or network computer (NC): Device designed to access a network for processing and data storageLower cost, increased security and easier

maintenanceLimited or no local storageNot able to function as a computer if network is

down Internet appliance: Specialized network

computer designed for Internet access and/or e-mail exchangeCan include Internet-enabled gaming consoles

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MIDRANGE SERVERS

Midrange server: A medium-sized computer used to host programs and data for a small networkUsers connect via a network with a

computer, thin client, or dumb terminalMay consist of a collection

of individual circuit boards called blades

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MAINFRAME COMPUTERS Mainframe computer: Powerful computer used

by several large organizations to manage large amounts of centralized data Standard choice for large organizations, hospitals,

universities, large businesses, banks, government offices

Located in climate-controlled data centers and connected to the rest of the company computers via a network

Larger, more expensive, and more powerful than midrange servers

Usually operate 24 hours a day Also called high-end servers or enterprise-class

servers

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MAINFRAME COMPUTERS

SUPERCOMPUTER

Supercomputer is a broad term for one of the fastest computer currently available.

Super computers were designed and built to work on extremely large jobs that could not be handled by no other types of computing systems.

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SUPERCOMPUTERS

Supercomputer: Fastest, most expensive, most powerful type of computerGenerally run one program at a time, as fast

as possibleCommonly built by connecting hundreds of

smaller computers, supercomputing clusterUsed for space exploration, missile guidance,

satellites, weather forecast, oil exploration, scientific research, complex Web sites, decision support systems, 3D applications, etc.

SUPERCOMPUTER (CONT’D)Supercomputers speed are measured in floating point operations per second (FLOPS) in units of megaflops (MFOPS) gigaflops (GFLOPS) teraflops (TFLOPS)

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SUPERCOMPUTERS

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COMPUTER NETWORKS AND THE INTERNET

Computer network: A collection of hardware and other devices that are connected together. Users can share hardware, software, and data Users can communicate with each other

Network servers: Manage resources on a network

Clients: Access resources through the network server

Computer networks exist in many sizes and types Home networks School and small business networks Large corporate The Internet

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COMPUTER NETWORKS AND THE INTERNET

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WHAT ARE THE INTERNET AND THE WORLD WIDE WEB? Internet: The largest and most well-known

computer network in the world Individuals connect to the Internet using an

Internet service provider (ISP) World Wide Web: One resource (a vast

collection of Web pages) available through the InternetWeb sites contain Web pages stored on Web

serversWeb pages viewed using a Web browser

(Internet Explorer, Chrome, Safari, Firefox, Opera, etc.)

A wide variety of information is available through the Web

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ACCESSING A NETWORK OR THE INTERNET

Need a modem or network adapter Some networks require a username and password Internet connections can be:

Direct (always-on) connections Dial-up connections

Internet addresses are used to access resources on the Internet IP address: Numeric address that identifies computers

(207.46.197.32) Domain name: Text-based address that identifies computers

(microsoft.com) Uniform resource locator (URL): Identifies Web pages

(http://twitter.com/jobs/index.html) E-mail address: Identifies people for e-mail exchange

(jsmith@cengage.com)

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COMPUTERS AND SOCIETY

The vast improvements in technology over the past decade have had a distinct impact on daily life, both at home and at work

Many benefits of a computer-oriented society:Ability to design products before construction

leads to safer productsEarlier medical diagnosesDocuments e-mailed or faxed in momentsDownload information, music, programs,

movies, and more on demand

COMPUTERS AND SOCIETY

Computer-oriented society also has risks Computer viruses and malware Identity theft and phishing Privacy issues

Information Integrity Check your source, not all information on the

Internet is accurate.

(c) Yngvi Bjornsson 48CMPUT101 Introduction to Computing

DESIGNING COMPUTERS

All computers more or less based on the same basic design, the Von Neumann Architecture!

(c) Yngvi Bjornsson 49CMPUT101 Introduction to Computing

THE VON NEUMANN ARCHITECTURE

Model for designing and building computers, based on the following three characteristics:

1) The computer consists of four main sub-systems:

Memory ALU (Arithmetic/Logic Unit) Control Unit Input/Output System (I/O)

2) Program is stored in memory during execution.3) Program instructions are executed

sequentially.

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THE VON NEUMANN ARCHITECTURE

Memory

Processor (CPU)

Input-OutputControl Unit

ALUStore data and program

Execute program

Do arithmetic/logic operationsrequested by program

Communicate with"outside world", e.g. • Screen• Keyboard• Storage devices • ...

Bus

18th August, 2005 CS431 Course Presentation 51

BOOTING OF A COMPUTER

SYSTEM

WHY IS BOOTING REQUIRED ? Hardware doesn’t know where the operating

system resides and how to load it. Need a special program to do this job –

Bootstrap loader. E.g. BIOS – Basic Input Output System.

Bootstrap loader locates the kernel, loads it into main memory and starts its execution.

In some systems, a simple bootstrap loader fetches a more complex boot program from disk, which in turn loads the kernel.

CS431 Course Presentation 5318th August, 2005

HOW BOOT PROCESS OCCURS ? Reset event on CPU (power up, reboot)

causes instruction register to be loaded with a predefined memory location. It contains a jump instruction that transfers execution to the location of Bootstrap program.

This program is form of ROM, since RAM is in unknown state at system startup. ROM is convenient as it needs no initialization and can’t be affected by virus.

BIOS INTERACTION

CS431 Course Presentation 5518th August, 2005

TASKS PERFORMED AT BOOT UP Run diagnostics to determine the state of

machine. If diagnostics pass, booting continues.

Runs a Power-On Self Test (POST) to check the devices that the computer will rely on, are functioning.

BIOS goes through a preconfigured list of devices until it finds one that is bootable. If it finds no such device, an error is given and the boot process stops.

Initializes CPU registers, device controllers and contents of the main memory. After this, it loads the OS.

BIOS SETUP

BOOT PROCEDURE

TASKS PERFORMED AT BOOT UP (CONTD) On finding a bootable device, the BIOS

loads and executes its boot sector. In the case of a hard drive, this is referred to as the master boot record (MBR) and is often not OS specific.

The MBR code checks the partition table for an active partition. If one is found, the MBR code loads that partition's boot sector and executes it.

The boot sector is often operating system specific, however in most operating systems its main function is to load and execute a kernel, which continues startup.

CS431 Course Presentation 5918th August, 2005

BOOTING AND ROM System such as cellular phones, PDAs and

game consoles stores entire OS on ROM. Done only for small OS, simple supporting hardware, and rugged operation.

Changing bootstrap code would require changing ROM chips. EPROM – Erasable Programmable ROM.

Code execution in ROM is slower. Copied to RAM for faster execution.