Obilor computer Literacy

7/28/2019 Obilor computer Literacy

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University of Ibadan, Ibadan

MacArthur Foundation Grant

ICT-Related Training Programme

Basic ComputerOperations


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Introduction to Computers


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WHAT IS A COMPUTER?

An electronic machine

Accept inputs(instructions and data)presented to it in aprescribed format frominput devices,

Carry out someoperations on the inputautomatically,

Supply the requiredresults (output) in aspecified format onoutput devices


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Characteristics of a Computer

system Speed

Large storage Capacity

Reliability

Automatic Diligence

Versatility

Electronic

Not a Substitute for Human Brain.


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Benefits of Computer to

Organizations

Dealing with increased volumes of

transaction

Better working conditions for staff

Better management of information

Better control over costs

Faster results


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Types of Digital computers

(based on processing power, size and

functions) Super Computers

Mainframe Computers

Mini Computers

Micro Computers


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SUPER COMPUTERS

Most powerful,

Most expensive,

Largest in size

The fastest. Used primarily for scientific applications in weather

forecasting, aircraft design, nuclear research, space

research, seismic analysis and task that require

mammoth data manipulation. An example of a supercomputer is Cray- 1

Supercomputer built by Cray Research Company.


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Mainframe

Process data at very high rates of speed

Very expensive (Millions of Naira)

Large (often filling an entire room) and

Designed for multiple users Serve as Servers for various company computers

Used in Banks, insurance companies, manufacturers,

mail-order companies, and airlines

Example of Mainframe computer is IBM 370 locatedat the University Computing Centre in the 1970s.


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Mini

Mini computers are smaller in size compare to main

frame computer

The cost is lower than that of Main-Frame

They possess most of the features found onmainframe computers, but on a more limited scale.

Used by medium size business organizations for

stock control and invoicing


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Micro Computers

Generally used in colleges and institute for teaching purpose.

Terribly limited in what they can do when compared to the largermodels discussed above because they can only be used by oneperson at a time,

Much slower than the larger computers,

Limited in storage capacity,

Excellent when used in small businesses, homes, and schoolclassrooms,

Comparatively inexpensive and easy to use

Often are connected to networks of other computers.

Price varies greatly depending on the capacity and features ofthe computer,

Make up the vast majority of computers.

Categorized into: desktop, Laptop, Notebook, Palmtop and PDA


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How computers Work

When a computer is asked to do a job, it handles the task in a very special way:

(1) It accepts the information from the user. This is called input.

(2) It stored the information until it is ready for use. The computer has memory chips, which are designed to holdinformation until it is needed.

(3) It processes the information. The computer has an electronic brain called the Central Processing Unit, whichis responsible for processing all data and instructions given to the computer.

(4) It then returns the processed information to the user. This is called output.

Every computer has special parts to do each of the jobs listed above

STORE

OUTPUTCOMPUTER

INPUT


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Components of a computer system


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Control Unit

Arithmetic &

Logic Unit

THE HARDWARE

SUBCOMPONENT

Central Processing Unit

A simple Computer Model

Input Unit Output Unit

Memory


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Input unit

The Input Unit consists of devices through which information tobe processed is passed on to the computer. Such devicestransform source information to be processed from humanreadable form into internal form which are transmitted to theCentral Processing Unit.

The most commonly used input devices are the keyboard andmice. There are lots of others such as: trackballs, touch pads,touch screens, pens, joy sticks, scanners, bar code readers,video and digital cameras, web cameras and microphones.


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Output Unit

The output unit consists of devices that change the internal form ofprocessed information (inform of electrical pulses) from the CPU intohuman readable or audible form. Common output devices include:

Printers Monitor Speakers

Headset Video output devices


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The Central Processing Unit (CPU)

The Central Processing Unit often referred to as the CPU ormicroprocessoris the brain of the computer. The CPU consistsof electronic circuits that interpret and execute instructions; itcommunicates with the input, output, and storage devices.

It is made up of the control unit and the arithmetic and logicunit.


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The Memory

Memory, or primary storage, works with the CPU to hold instructions and data in order to be processed.

Memory keeps the instructions and data temporary for whatever programs you happen to be using at themoment.

Memory is the first place data and instructions are placed after being input; processed information is placedin memory to be returned to an output device.

The size of your computer memory is one of the factors that determines how fast your computer will be

Memory is measured in Mega bytes (MB)


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Units of measurement for memory

and storage devices Memory is usually measured in Megabytes; a typical.

Storage is usually measured in Gigabytes.

Byte Byte 8 bits (amount of storage for a character)

Kilobyte KB Roughly 1,024 bytes

Megabyte MB Roughly 1,000,000 bytes

Gigabyte GB Roughly 1,000,000,000 bytes

Terabyte TB Roughly 1,000,000,000 bytes


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External Storage Devices

Provide a permanent form of storage.

Provides large space capacity,

Provides reliability of stored information,

Convenience and

Economical.


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Floppy disk or FloppyHard disk (drive) or HD

A round plastic surface that is coated with magnetic film. They come in

31/2size.

They hold about 720k to 1440K of information. They are typically are

used to install new software, save, share, and/or copy files. Floppy

drives are given letters. Commonly the floppy is A, a 2nd floppy is B and

the hard drive is C.

A stack of round metal platters called disks encased in a metal air tight

shell. They commonly range in sizes from 1 to 250 gigabytes . The hard

drive's function is to store all the files, and software the computer will ever

use. Any file or software program used by RAM most likely will come from

the disk drive.

CD-ROM (Compact disk, read-only memory) DVD-ROM (digital video disk, read-only memory)

CD's function much like hard drive in that they store large amounts of

memory. What separates them is their mobility and optical storage

technology. Their storage capacity is also very limited compared to hard

drives. The can only hold up to approximately 700 MB of

information. The other big difference is that you have to have a special

drive to write to CD's. Otherwise they can only be read from.

DVD's are similar to CD in that they are written and read by laser. Hard

drives use magnetic currents store data. However CD's and DVD's use light

(laser) to write and read data on a disk. These long and short pits are then

stored or etched on the surface of the disk. They can only be read by laser

technology. The new DVD technology increased the amount of memory a

regular CD can hold. DVD's can range in sizes from 4.34GB

(1000MB=1GB) to 7.95GB.

FLASH DRIVEA small, portable flash memory card that plugs into a computers USB port and functions as a portable hard drive. USB flash d rives are touted as being

easy-to-use as they are small enough to be carried in a pocket and can plug into any computer with a USB drive. USB flash drives have less storage

capacity than an external hard drive, but they are smaller and more durable because they do not contain any internal moving parts. USB flash drives also

are called thumb drives, jump drives, pen drives, key drives, tokens, or simply USB drives. Flash drives come with varying amounts of storage capacity eg

128MB, 256, 4.5GB. Popular brand name drives, are Lexar, Sandisk, Kingston, PNY, Iomega and LG.


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Software Subcomponent

Consists of all programs that tell a computer

what to do.

Categorized into:

1. Application

2. System

3. Programming


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Application Software

Application software or package helps you accomplish specific tasks. You can use application software towrite letters, manage your finances, draw pictures, play games and much more.

TypesWord Processor

Spreadsheets

Database Management

Presentation Graphics

Communication Software

Internet BrowserAccounting Packages

Statistical Packages

Desktop Management

Graphic Packages

Games/Entertainment

Audit Packages

Tutorials


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System Software

The systems Software manage computer resources

and interact with both the user and application

programs. System software helps run the computer

hardware and computer system. It includes:

device drivers,

diagnostic tools,

operating systems,

servers,utilities,

windowing systems


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Programming Software

Programming software usually provides tools toassist a programmer in writing computer programs,and software using different programming languagesin a more convenient way. The tools include:

compilers,

debuggers,

interpreters,

linkers,

text editors


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Operating System

An operating system is a software component of acomputer system that is responsible for themanagement of various activities of the computer andthe sharing of computer resources.

The most important program that runs on your

computer. It manages all other programs on themachine

Every PC has to have one to run other applications orprograms. Its the first thing loaded.


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Some Basic Task of the OS

Recognizing input from

the keyboard or mouse,

Sending output to the

monitor,


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Some Basic Task of the OS

Keeping track of files and

directories on the disk,

and

Controlling peripheral

devices such as diskdrives and printers.


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Types of Operating System

Windows VistaWindows XP

Windows 2000

Windows NT

Windows 98Windows 95

Unix

Linux

Apple MacIntosh


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Starting the Computer

Use the front power button to switch on the computer. If it does notpower up, you should check to see that the rear power supply switch isset to the '1' position. The '0' position is OFF. If the computer still fails topower up, you should check and see that it's plugged into a workingoutlet and make sure that the power strip's (UPS) main power switch isin the ON position (if you have a power strip). Most power strips havean indicator lamp to let you know that they're on AND that the strip is

plugged into a working outlet. Assuming that your computer is in goodworking order, it will come on when you push the main power button.When it powers up, the 'power' light will be lit and the hard drive activitylight will be flashing/flickering. You will also hear the hard drives 'spinup' and you'll likely hear at least one fan turn on.

Now that the computer is on, you should see a 'desktop' with 1 or moreicons (little images that indicate what software/function they represent)and a background image (the background may also be a solid color ora pattern). This background image is called 'wallpaper'


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Shutting Down the Computer

To shut down Windows XP:

Click the Start button.

From the Start menu, choose Turn Off Computer. Click the Turn Off button.


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WORKING WITH WINDOWS

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