SESSION 1

1

GRE-GRADUATE RECORD EXAMINATION; GMAT-The Graduate Management Admission Test; The SAT – Scholastic Aptitude Test.

3

Computer: An electronic machine that takes data, stores it, processes that data and produces information.

OR

Computer: can be defined as a machine which manipulates data according to a stored program executed within it.

OR

A computer: is a machine or device which accepts input data in one form and processes it to produce an output of information.

Data: are raw facts or elementary descriptions.

Processing data gives information.

Data are processed by the CPU, which uses logical operations to produce new data (output) from source data (input).

4

5

A computer responds to a specific set of instructions in a well-defined manner.

A computer can execute a pre-recorded list of instructions (a program).

Other Characteristics are

SPEED: In general, no human being can compete to solving the complex computation, faster than computer.

ACCURACY: Since Computer is programmed, so what ever input we give it gives result with accurately.

STORAGE: Computer can store mass storage of data with appropriate format.

DILIGENCE: Computer can work for hours without any break and creating error.

VERSATILITY: We can use computer to perform completely different type of work at the same time.

NO IQ: Computer does not work without instruction.

NO FEELING: Computer does not have emotions, knowledge, experience, feeling.

6

Computers can be classified by size and power.

Workstation

Powerful desktop computers designed for specialized tasks such as medical imaging. Such tasks require a lot of processing speed.

It is a single-user computer

They have the power to handle complex engineering applications.

They use the UNIX, or sometimes NT, operating system.

It is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.

7

Minicomputer

A multi-user computer: Smaller than mainframe but more powerful than Micro-computer.

computers that are capable of supporting from 10 to hundreds of users simultaneously.

These are large powerful machines typically serving a network of simple terminals.

For example of a minicomputer; Digital Alpha, Sun Ultra.

Very powerful and expensive

Used in medium scale organizations where it is too expensive to use mainframe computers

8

A picture of minicomputer

9

Figure

Source

2

Minico

F

ittel, 2002

m

pute

r

10

Mainframe

These are the very largest computers; they are million-dollar machines, which can occupy more than one room.

For example: IBM 370, S/390.

A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously like ATM Transactions.

They are

Large in size

Expensive due to high cost of production

High storage capacity and high processing speed

Used in organization to process a bulk of information

Generally used by large businesses to provide centralized storage, Processing and management for large amounts of data.

11

A picture of Mainframe computer.

12

Supercomputer

This is an extremely fast computer that can perform hundreds of millions of instructions per second.

It is a computer that leads the world in terms of accuracy, speed and precision.

Super computers are used in military and research institutions

Very accurate

High processing speed

Can tackle complex tasks such as breaking codes and modeling worldwide weather system.

An example of supercomputer: IBM Deep Blue

13

A picture of Supercomputer

14

Personal Computer (PC)

Is a small, relatively inexpensive computer designed for an individual user.

Classified by size and portability as follows

Desktop Computers

Laptops

Notebooks

Personal Digital Assistants(PDA) / Hand held / Palmtop.

Tablet Computers

Wearable Computers /smart watch

Cell Phones

All are based on the microprocessor technology that enables manufacturers to put an entire Central Processing Unit (CPU) on one chip.

15

Laptop Notebook

Palmtop (Hand held) Wearable computer

16

A computer (or software) on a network that is responsible for distributing resources to other computers such as files and disk space.

A server can be any computer but for a large network it is preferred to be a mainframe or supercomputer.

They can be in a position to respond to requests quickly and they have a lot of storage thus large amounts of files can be stored.

17

Factors that Impact a Computer’s Performance

You may be wondering why your computer is slow at times and there are other times when it is fast in processing.

This could be caused by a number of factors.

They include

The speed of the CPU

The higher the processor speed, the faster the computer.

The speed of the CPU is also known as the clock speed of the CPU.

It is measured in millions of cycles per second or megahertz (MHz).

If the Clock speed of the CPU is fast then definitely the performance of the computer will be affected positively, in other words the computer will carry out processing functions at a faster pace.

18

The size of the RAM (Random Access Memory)

The more memory you have (RAM), the faster the PC will appear to operate.

The RAM is referred to as the active part of the computer.

RAM has the capability of storing data that the computer is currently using, because of the fact that it is fast to retrieve data stored in the RAM.

A large RAM size will mean a faster computer performance and a smaller RAM size will result to slower computer performance.

The speed of the hard disk

Is the rate at which material and content can be read and written on it.

The hard disk speed of different hard disks is not consistent because they vary by manufacturer, drive type and the use of the hard disk.

It therefore means that the higher the speed of the hard disk the faster the performance of the computer and vice versa.

19

Hard disk space

The bigger the space on the hard disk will result to faster performance of the computer.

The smaller the space on the hard disk will result in a slower performance of the computer.

Multiple applications running on the computer

The more programs which are running at the same time, the slower each one will run.

Multi-tasking tends to slow down the performance of the computer because memory is used to support more than one applications compared to when one application has all the memory to itself.

This means that the more applications that are running the slower the computer will perform.

Likewise if less or one application is running the performance of the computer will be faster.

20

Type of graphic card

When it comes to quality of pictures and animations graphic cards are the main factors.

So if a machine processes many graphics and it has a weak graphic card it will perform slower.

This means that the more powerful the graphic card is the faster the performance of the computer.

Spyware

These are illegal programs which come onto your computer usually while browsing or surfing through the Internet.

You can get rid of them by using ant-spyware programs or reformatting the computer.

21

There are two uses of computer, these are

General purpose computer is design to solve wide variety of problems. Examples of general purpose computer are

School computers

Hospital computers

Office computers

22

Special purpose computer is designed for particular job only to solve problem of restricted nature. Examples of special purpose computer are

Petroleum pumps

Traffic lights

Programmable pocket calculator

Weapons guidance system

23

Other uses of computer

Education: computers can significantly enhance performance in learning and teaching.

For example

Computer Aided Learning (CAL): Is the process of using information technology to help teaching and enhance the learning process.

The use of multimedia projector and PowerPoint presentations has improved the quality of teaching.

It has also helped the learning process.

Distance Learning: Many institutes are providing distance learning programs.

The institute provides the reading material and the student attends virtual classroom.

24

In virtual classroom, the teacher delivers lecture at his own workplace.

The student can attend the lecture at home by connecting to a network.

The student can also ask questions to the teacher.

Online Examination: The trend of online examination is becoming popular.

Different examination like GRE, GMAT and SAT are conducted online all over the world.

The questions are marked by computer.

It minimizes the chance of mistakes.

It also enables to announce the result in time.

25

Health and Medicine: computer technology is radically changing the tools of medicine.

For example

Patient History: Hospital management systems can store data about patients.

Computers are used to store data about patients, their diseases & symptoms, the medicines that are prescribed.

Patients Monitoring: Monitoring systems are installed in medical wards and Intensive care units to monitoring patients continuously.

These systems can monitor pulse, blood pressure and body temperature and can alert medical staff about any serious situations. e.t.c

26

Business: Businessmen use computers to interact with their customers anywhere in the world.

Computers also help them to reduce the overall cost of their business.

for example

Marketing: An organization can use computers for marketing their products.

Marketing applications provide information about the products to customers.

Computer is also used to manage distribution system, advertising and selling activities. It can also be used in deciding pricing strategies.

Stock Exchange: Many stock exchanges use computers to conduct bids.

The stockbrokers perform all trading activities electronically.

They connect with the computer where brokers match the buyers with sellers.

It reduces cost as no paper or special building is required to conduct these activities.

27

Recreation and Entertainment

For example;

In movies, computer generated graphics give freedom to designers so that special effects and even imaginary characters can play a part in making movies, videos, and commercials.

In sports, computers compile statistics, sell tickets, create training programs and diets for athletes, and suggest game plan strategies based on the competitor’s past performance.

28

The keyboard has the following keys

Enter or Return – Moves the cursor down one line and to the left margin. Enter also process commands such as choosing an option in a dialog (message) boxes and submitting a form

DEL or Delete – Deletes the character at cursor and/or characters to the right of the cursor and all highlighted (or selected) text

BKSP or Backspace – Deletes the character to the left of cursor and all highlighted text

Space Bar – Moves the cursor one space at a time to the right

Shift Key – Use the shift keys to type capital letters and to type the upper character on keys with two characters on them

29

Caps Lock – Locks the keyboard so it types capital letters (a light goes on when caps lock is on)

Tab – Moves the cursor five spaces to the right (number of spaces are usually adjustable). Tab moves to the next field in a form or table (Shift-Tab for previous field).

ESC or Escape – Cancels a menu or dialog box

Arrow Keys – Moves the cursor around document without changing text

Function Keys or F keys – Access commands by themselves or in combination with the three command keys; CTRL, SHIFT, and ALT

30

Command keys normally do nothing on their own but work in combination with other keys

Each piece of software uses the command keys differently though there is a move to standardize some functions

The Control key or Ctrl is often used to access commands

The Alternative key or Alt is often used to access menus

The Shift key is used to type CAPITAL LETTERS

31

The command keys are all used to move through documents and edit text faster and easier

Many computers have special keys designed specifically for the particular computer

Apple computers have the Apple keys and Macs have Command keys

Many older computers also have special keys used for a variety of different functions

Some laptop keys are left out because of space limitations and they usually have a special function key which allows other keys to double for the missing ones

32

Keyboard Shortcuts for Windows

CTRL+ESC: Open Start menu

ALT + Tab: Switch between open programs

ALT+F4: Quit program

Shift + Delete: Delete item permanently

Windows Program Key Combinations

CTRL+C: Copy

CTRL+X: Cut

CTRL+V: Paste

CTRL+Z: Undo

CTRL+B: Bold

CTRL+U: Underline

CTRL+I: Italize

33

General Keyboard-Only Commands

F1: Starts Windows Help

F5: Refreshing

F10: Activates menu bar options

Shift+F10: Opens a shortcut menu for the selected item (this is the same as right-clicking an object

CTRL+ESC: Opens the Start menu (use the arrow keys to select an item)

ALT + Tab: Switch to another running program (hold down the ALT key and then press the Tab key to view the task-switching window)

34

Basically there are two types of Typing, these are

Touch typing: This is a method of using the ‘home keys’, in which all the fingers on both hands are used, as well as the thumbs for the space bar while typing.

There are many commercial and public domain programs that are designed to teach this method.

Hunt and Peck- Involves using one or more finger on one or two hands to type.

Many people get along fine with this technique but speed can be a challenge.

35

Place one space between each word, after a punctuation mark and at the end of a sentence.

Always start a sentence with a capital letter.

Use capitals for names, addresses, provinces and countries, places, organizations, businesses, associations, schools, colleges, universities, days of the week, months, holidays, nationalities, ethnic groups and languages.

36

Take into consideration aspects like electrical safety, eyestrain, wrist strain, etc.

Even if one uses a computer for only for a few hours per week, improper computer use can affect health.

By following a few simple ideas, we can improve the working conditions and our own safety when using the computers.

The Main Areas of Concern

Eye strain

Back and wrist problems

Electrical safety

37

Eye Strain

Medical evidence now suggests that working with a video display unit (VDU) does not cause eye defects.

It can however lead to temporary impairments in vision, sore eyes or discomfort in the neck, shoulders and arms.

Staring at a screen for long hours is not good for your eyes.

Factors like poor background lighting, reflections on the screen caused by bright sunlight, flickering screens, sitting too close or too distant from the screen all contribute to eye problems.

38

Reducing Discomfort

Provided you have a modern monitor most of these problems can be reduced dramatically, if not eliminated.

Increase monitor size: Modern monitors have a screen size of 17″ – 19” (diagonal). This ensures that you can see the screen easily.

Many software packages allow you to zoom in on the text, magnifying the screen image and making it easier to read.

Special software, e.g. zoom text, allows you to magnify the screen image exceptionally large and is intended for users who are partially sighted.

39

Monitor position

Monitors should be adjustable, up, down left to right, to give the best reading position.

The monitor should be tilted slightly upwards so that you are looking down at the screen

Brightness and contrast

Adjust the brightness and contrast to minimize discomfort. Most software allows you to adjust the colors of the menus and text.

Customize colors to your own choice to minimize discomfort and make it easier to read.

40

In cases of laptops where the screen is smaller and often more difficult to adjust, if you are going to use a laptop for long periods where conditions allow at home or in the office, invest in a larger monitor to attach to your laptop.

Take regular breaks away from the computer.

A break of 5 minutes every hour gives your eyes a chance to adjust back to normal.

41

Back and Wrist Problems

One of the major problems arising when using a computer is the increase in the number of back problems and repetitive strain injury (RSI), which damages the wrists.

To avoid bad posture the computer should have the monitor at eye level.

Repetitive strain injury is caused by incorrect positioning of the hands when typing or using the mouse.

Use of the keyboard and the mouse over many years causes painful problems in the wrists.

Correct positioning of the hands above the keyboard rather than resting the wrists on the table can overcome this.

Careful positioning of the computer and the purchase of suitable chairs and desks can reduce many of these problems.

42

Bad Posture

Two major aspects can improve the potential risk: Designing a good work area for your computer, Sitting correctly

Buy one of the many products, trolleys or desks, where your computer fits onto shelves so taking up less room.

Ideally you want a desk with plenty of space for all of the computer equipment.

You need space for the mouse, the keyboard and paperwork, without the need for overly stretching to get to the equipment.

If you are copying text from paper, invest in a document holder which can be attached to the monitor, leaving your desk uncluttered but more importantly, saving you from looking up and down at the paper and then at the monitor.

43

Buy an ergonomically correct chair

The chair should swivel on castors, it should be adjustable, both up and down, and give back and side support so that you are positioned at the correct height for typing

This reduces back problems by correct positioning.

You should also have a footstool.

The position of the VDU is important in preventing discomfort.

Regulations on VDUs require that all VDUs have a swivel and tilt capability.

Most VDUs are mounted on some kind of pedestal.

44

Electrical Safety

Although the computer processor works at a very small current, power into the computer and its peripheral devices such as printers, monitors, are at normal household voltages.

Care should be taken when attaching power leads or changing over devices, which are often at the back of the computer and usually in difficult situations.

Take the same care as you would when working with any electrical appliance.

45

Use a computer parts to complete activities 1 through 4 listed below

Connect monitor and system unit together.

Connect keyboard.

Connect mouse

Connect computer to electrical power.

46

Computer is like other electronic equipment like Television or radio.

It has on/off button.

When switch on computer you just press the button and it will start automatic.

The process is called booting.

Turning off is different from other devices because you have to follow procedures.

47

After activity 1 continue with demonstration of switching on/off computer

Switch on computer

Switch off computer