computer 1 lecture

8/8/2019 Computer 1 Lecture

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Computer 1Computer 1

(Introduction to Computer Concepts and Software)


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Unit 1: Computer BasicsUnit 1: Computer Basics

The Computer SystemA computer is a programmable machine. It allows the user tostore all sorts of information and then process thatinformation, or data, or carry out actions with theinformation, such as calculating numbers or organizing words.

Computer:A machine that can receive and storeinformation and change or process it.

Information:Knowledge that is communicated.

Data (pl.):The representation of information in a formalizedmanner suitable for communication, interpretation and

processing, generally by a computer system.Note: the termraw data refers to unprocessed information.


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Four Basic FunctionsFour Basic FunctionsAll computers perform four basic functions:

y The computer accepts input. Computer input is whatever is entered or fed into acomputer system. Input can be supplied by a person (such as by using a keyboard) or byanother computer or device (such as a diskette or CD-ROM). Some examples of inputinclude the words and symbols in a document, numbers for a calculation, instructions forcompleting a process, pictures, and so on.

y The computer performs useful operations, manipulating the data in many ways.Thismanipulation is called processing. Examples of processing include performing calculations,sorting lists of words or numbers, modifying documents and pictures according to userinstructions, and drawing graphs.A computer processes data in the CPU.Process:A

systematic series of actions a computer uses to manipulate data.y The computer stores data.A computer must store data so that it is available for

processing. Most computers have more than one location for storing data (the hard driveor C:\, and the floppy drive orA:\).The place where the computer stores the datadepends on how the data is being used.The computer puts the data in one place while itis waiting to be processed and another place when it is not needed for immediateprocessing.The storage of data in the computer is called online storage while the storageof data on computer tapes, diskettes or CD-ROMs is called offline storage.

y The computer produces output. Computer output is information that has beenproduced by a computer. Some examples of computer output include reports, documents,music, graphs, and pictures. Output can be in several different formats, such as paper,diskette, or on screen.

Note: A computer receives data as input, processes it, stores it and then produces output.


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Computer AdvantagesComputer Advantages

The use of computer gives us very real advantages. Thefollowing list of advantages is what makes a computer abetter tool than others for specific tasks.

Speed once data has been stored into a computer, the

computer cam process data into information much fasterthan any human being using any other tools.A computer cando billions of actions per second.

Accuracy if the computer has been given the correctinstructions (program), the information it will provide will betotally and consistently accurate.

Repeatability this is the computers capability of doing thesame task repeatedly. Quickly and without complaint.

Programmability computers have the advantage of beingprogrammable.


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Components of ComputerComponents of Computer

systemsystemComputers are made up of two parts: thehardware and the software.

Hardware:The physical equipment

required to create, use, manipulate and

store electronic data.

Software:The computerised instructions

that operate a computer, manipulate thedata and execute particular functions or

tasks.


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Hardware component ofHardware component of

computer systemcomputer systemAll computers require the following hardware

components:

Central processingunit (CPU):The chip orchips at the heart of a computer that enable it toprocess data.Also known as a processor.Thefaster the processor in a computer, the more quicklythe computer will perform operations.

Memory:An area within a computer system thatholdsdata waiting to be processed.The most

common type of memory that most users arefamiliar with is main memory or RAM (random-access memory).Random access memory(RAM):An area in the computer system unit thattemporarily holds a users data, operating systeminstructions and program instructions.


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computer systemcomputer system Storage device: The place where a computer puts

data.The area within a computer system where data canbe left on a longer term basis while it is not needed forprocessing.

Following are common storage devices:

Diskette.A small, removable, flexible mylar plastic disk

covered with a thin layer of a magnetisable substance, onto which digital data can be recorded and

stored.Also known as a floppy disk.

Hard drive:The storage area within the computer itself,where megabytes of space are available to store bits ofinformation.Also known as a hard disk.

Optical disk: A storage device that uses reflectingsurfaces and laser technology to read and write data on adisk.Also known as a laser disk.

Magnetic tape:A continuous plastic strip covered withmagnetic oxide; the tape is divided into parallel tracksonto which data may be recorded by selectivelymagnetising parts of the surface, or spots, in each of thetracks.The data can then be stored and reused.


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input devices : the devices thatallow data and instructions to entera computer (such as a keyboard,mouse, scanner) Input:Anyresource required for thefunctioning of a process, in thecourse of which it will betransformed into one or moreoutputs.

output devices: the devices thatallow information to be represented

(that is, given out) to the user, suchas a display screen or printer)Output:The product of thetransformation of inputs by aprocess.


computer systemcomputer system


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Software Components ofSoftware Components of

ComputerSystemComputerSystem System Software is essentially the master controller for all

the activities that takes place within a computer. Operatingsystems are classified as system software.

Example: Microsoft Windows, Mac OS, Linux and Unix

Application Software is a set of computer programs thathelps a person carry out a task.

Example: Word processing software, ElectronicSpreadsheet, Presentation software, video/image editing andmany more.

Programming Language -

An artificial set of rules,vocabulary and syntax used to instruct the computer to

execute certain tasks. Computer program:A sequence ofinstructions that can be executed by a computer to carryout a process.


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Computer CategoriesComputer Categories

Categorizing computers is way of

grouping them according to criteria such

as usage, cost, size, and capability.

y Supercomputers

y Mainframe computers

y Minicomputers

y Workstations

y Microcomputers, or personal computers


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SupercomputerSupercomputer

Supercomputers are the most powerful

computers made, and physically they are

some of the largest.These systems are built

to process huge amounts of data, and thefastest supercomputer can perform more

than 1trillions calculations per second.


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MainframeMainframe

y Mainframe computers areused in large organizationslike insurance companies andbanks where many peopleneed frequent access to the

data, which is usuallyorganized into one or morehuge databases.

y Aside from the obviousdifferences in processing

speed, the major differencebetween minicomputers andmainframes is the number ofremote terminals serviced.


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MinicomputersMinicomputers

y First released in the 1960s,minicomputers got theirname because of their smallsize compared to other

computers of the day.y The capabilities of a

minicomputer aresomewhere betweenmainframes and personal

computers.T

he mostpowerful minicomputer canserve the input and outputneeds of hundreds of users ata time.


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WorkstationWorkstation

y Workstations are specialized, single-usercomputers with many of the features of apersonal computer but with the processingpower of a minicomputer. It typically uses

advanced processors and feature more RAMand storage capacity than personalcomputers.

y Workstations often have large, high-

resolution monitors and acceleratedgraphics-handling capabilities, in making themperfect for advanced design, modeling,animation, and video editing.


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MicrocomputerMicrocomputer

y This machine has taken fullest advantage of the use oflarge - scale integration on silicon chips.Themicroprocessors literally contain a computer on achip that can pass through the eye of a needle. It isgenerally made of semiconductors fabricated on

silicon chips.


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Personal computers come infourPersonal computers come infour

different physical sizes:different physical sizes:

y pocket PCs (palmtop)

y Lap top PCs (small ones are notebook PCs)

y desktop PCs

y tower PCs


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Personal computer systemPersonal computer system

equipments:equipments:y System unit.The system unit is the case that holdsthe main circuit boards, microprocessor, powersupply, and storage devices.

y Display Device. Most desktop computer use a

separate monitor as a display device, whereasnotebook computers use a flat panel LCD screenattached to the system unit.

y Keyboard. Most computers are equipped with akeyboard as the primary input device.

y Mouse.A mouse is an input device designed tomanipulate on-screen graphical objects and controls.

y Hard disk drive.A Hard disk drive can store billionsof characters of data. It is usually mounted inside thecomputers system unit.


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Personal computer systemPersonal computer system

equipments:equipments:y CD and DVD drive.A CD/DVD drive is a storage device that

uses laser technology to work data on computer or audio CDs.

y Floppy disk drive. Floppy disk drive is a storage device that readsand writes data on floppy disks.

y Sound card and speaker. Desktop computer have a rudimentarybuilt-in speaker thats mostly limited to playing beeps. A smallcircuit board, called a sound card, is required for high-quality music,narrator, and sound effects.

y Modem and Network card. Many personal computer systemsinclude a built-in modem that can be used to establish an internet

connection using a standard telephone line. A network card is usedto connect a computer to a network or cable internet connection.

y Printer. A computer printer is an output device that producescomputer generated test or graphical images on paper.


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Unit 2. Operating a PersonalUnit 2. Operating a Personal

ComputerComputery Windows

Windows is a graphical user interface

program or GUI (pronounced gooey)

which makes interacting with you computereasy. A GUI is an alternative to a command-

line interface, where text commands are

entered from the keyboard. Windows is

faster, more powerful, and gives you better

performance when doing several computer

things at the same time.


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To start windows:To start windows:

y Locate the power switch for any devicesconnected to your computer and turnthem on.

y Locate the power switch for yourcomputer and turn it on.

y If a message asks for your user ID and/orpassword, type them in, and then pressthe enter key on your computerskeyboard.

y Wait for the Windows desktop to appear.


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Windows DesktopWindows DesktopT

he windows desktop is your base of operations for usingyour computer. The desktop is divided into several areas:

y Icon. The main part of the desktop displays icons thatrepresent software, files and folders containing documents,graphics and other data.

y Taskbar. The taskbar contains the Start button, Quick start

bar, and Notification area.y Start button. The start button is used to display the start

menu, which lists all the programs installed on yourcomputer.

y Quick start bar. The quick start bar is always visible,making it s good place for icons that represent the programs

you frequently use.y Notification area. The notification area displays the

current time and status of programs, devices and internetconnections.

y Mouse pointer. The on-screen pointer (usually an arrow)that you use to select items and choose commands.


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TheThe UbuntuUbuntu DesktopDesktop

y Ubuntu(pronounced oo-boon-too) is aSouthAfrican ethical idealogy focusing onpeople's allegiances and relations with eachother.The word comes from the Zulu and

Xhosa languages.y Ubuntu 10.04, also known as the Lucid Lynx,

arrived onApril 29, 2010 and it is the 12threlease of the Ubuntu operating system.

y Ubuntu is an entirely open source systembuilt around the Linux kernel.

A kernel is an important part of any

operating system, providing the communication

bridge between hardware and software.


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GNOME desktopGNOME desktop

y One of the most popular desktop

environments which is used by default in

Ubuntu.


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Major components of theMajor components of the

GNOMEDesktopGNOMEDesktop

y Desktop

The desktop itself is behind all of the othercomponents on the desktop. You can place objectson the desktop to access your files and directories

quickly, or to start applications that you use often.

y Panels

The panels are the two bars that run along the topand bottom of the screen.A panel is a bar that sits onthe edge of your screen and contains various applets.These applets provide useful functions such asrunning programs, viewing the time, or accessing themain menu.


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Top PanelTop Panely T

his includes menu headings- Applications,Places, and System-followed by twoprogram icons.The Firefox web browser andthe next will open the Ubuntu help Center.On the right side of their panel is the

notification area, which is similar in functionto the system tray in Windows.On the far right of the panel is the sessionmenu, which provides menu options for

locking the computer logging out, restarting,or shutting down completely.


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Bottom PanelBottom Panel

y The bottom panel is used to display a list

of all programs or windows that are

currently open.


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Using the Application menuUsing the Application menu

There are three menu headers in the toppanel. Lets take a look at these in moredetail, starting with theApplications menu.

y Accessories

y Games

y

Graphicsy Internet

y Office

Open office.org Word Processor

Open office.org Spreadsheet

Open office.org Presentation

Open office.org Drawing (located under theGraphics sub-menu)

y Sound andVideo

y Ubuntu Software Center


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System MenuSystem Menu

y The System menucontains two importantsub-menus;

Preferences andAdministration.These allows you tomake modifications to

Ubuntus appearance,as well as the way itfunctions.


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System subSystem sub--menusmenus

y Preferences

Modify the appearance of the desktop and windows,assign a default printer, designate keyboard shortcuts,change the entries listed in the Applications menu,edit network connections, and change mouse settings,among other options.

y Administration

It contains programs you can use to monitor

computer performance, change disk partitions,activate third-party drivers, manage all installedprinters, and manage how your computer receivesupdates from Ubuntu.


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Browsing files on yourBrowsing files on your

computercomputer

Two ways to locate files on your computer:y Search for Files tool in the Applications menu,

under Accessories.

y You can also use the Places menu on the top panel.

Places

The Places menu holds a list of commonly usedfolders (such as Documents,Music,Downloads,and the Home Folder).

Home Folder

The home folder is where all users personal files arelocated.


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WorkspacesWorkspaces

y Workspaces allow you to manage whichwindows are on your screen. Every

workspace contains the same desktop,

the same panels, and the same menus.

However, you can run different

applications, and open different windows

in each workspace.The applications in

each workspace will remain there whenyou switch to other workspaces.