1. INTRODUCTION TO ICT

Definition:

ICT (information and communications technology - or technologies) is a term that includes any communication device or application, encompassing: radio, television, cellular phones, computer and network hardware and software, satellite systems and so on, as well as the various services and applications associated with them, such as videoconferencing and distance learning. ICTs are often spoken of in a particular context, such as ICTs in education, health care, or libraries.

Or

ICT stands for Information and Communication Technology and are defined as a set of technological tools and resources used to communicate, create, disseminate, store and manage information.

These tools include computers, the internet, broadcasting (radio and Television)

The importance of ICTs lies less in the technology itself than in its ability to create greater access to information and communication in undeserved populations. Many countries around the world have established organizations for the promotion of ICTs, because it is feared that unless less technologically advanced areas have a chance to catch up, the increasing technological advances in developed nations will only serve to exacerbate the already-existing economic gap between technological "have" and "have not" areas. Internationally, the United Nations actively promotes ICTs for Development (ICT4D) as a means of bridging the digital divide.

Digital divide is a term that refers to the gap between demographics and regions that have access to modern information and communications technology, and those that don't or have restricted access. This technology can include the telephone, television, personal computers and the Internet.

2. INTRODUCTION TO COMPUTERS

What is a computer?

A computer is a general-purpose electronic machine that receives / accepts, processes, stores and output data into meaningful information

A computer can also be defined as an electronic device operating under control of instructions stored in its own memory that can accept data, manipulate the data according to specified rules, produce results, and store the results for future use.

Characteristics of Computers.

Ø  Speed: The computers process data at an extremely fast rate, at millions or billions of instructions per second. A computer can perform a huge task in a few seconds that otherwise a normal human being may take days or even years to complete. The speed of a computer is calculated in MHz (Megahertz), that is, one million instructions per second.

Ø  Accuracy: Besides the efficiency, the computers are also very accurate. The level of accuracy depends on the instructions and the type of machines being used. A computer in other wards does not make any mistakes. For example a computer can accurately give the result of division of any two numbers up to 10 or more decimal places

Ø  Diligence: Computer, being a machine, does not suffer from the human traits of tiredness and lack of concentration. If four million calculations have to be performed, then the computer will perform the last, four-millionth calculation with the same accuracy and speed as the first calculation.

Ø  Reliability: Generally, reliability is the measurement of the performance of a computer, which is measured against some predetermined standard for operation without any failure.

Ø  Storage Capability: Computers can store large amounts of data and can recall the required information almost instantaneously i.e. data can be retrieved whenever required.

Ø  Versatility: Computers are quite versatile in nature. It can perform multiple tasks simultaneously with equal ease. For example, at one moment it can be used to draft a letter, another moment it can be used to play music and in between, one can print a document aswell.

Ø  Resource Sharing: In the initial stages of development, computers used to be isolated machines. With the tremendous growth in computer technologies, computers today have the capability to connect with each other. This has made the sharing of costly resources like printers possible. Apart from device sharing, data and information can also be shared among groups of computers, thus creating a large information and knowledge base.

2.1. uses of ICT in different sectors

Health

Nearly every area of health care uses computers whether you are visiting a family doctor for a regular check-up.

Ø  Hospitals and doctors use computers to maintain patients records.

Ø  Computers monitor patients" vital signs in the hospital room and at home.

Ø  Computers and computerized devices assist doctors, nurses and technicians with medical tests.

Ø  Doctors use the web and medical software to assist with researching and diagnosing health conditions.

Ø  Doctors use e-mail to correspond with patients.

Ø  Pharmacists use computers to file insurance claims.

Ø  Surgeons use computer-controlled devices to provide them with precession during operations such as for laser eye surgery and robot assist heart surgery.

Ø  Surgeons implant computerized devices, such as pace makers that allow patients to live longer.

Ø  Many websites provide up-to date medical fitness, nutrition or exercise information. These Websites also maintain lists of doctors and dentists to help you find the one that suits your need.

Ø  They have chart rooms so you can talk to others diagnosed with similar conditions.

Ø  Websites even allow you to order prescriptions online. An exciting development in health care is telemedicine, which is a form of long-distance health care.

Ø  Through telemedicine, Health care professionals in separate locations have live conferences on computers e.g. doctors at another location to discuss a bone X-ray live images of each doctor along with the X-ray are displayed on each doctor's computer.

Security

Ø  Use of CCTV cameras to monitor supermarkets for shop lifters / thieves and to monitor crucial buildings like banks, parliament e. t. c.

Ø  Use of traffic camera to track traffic offenders.

Ø  Use of biometric devices like finger print scan, iris scan to keep records of right employees.

Ø  Mobile phones have tracking records used to track down rebels and suspected criminal.

Ø  Walkie talkies that are used in communication by armies and police.

Ø  Surveillance cameras that help in capturing criminals.

Computers are used by police and other security

2.2. Part of a computer system

User

Data and information

Data is a collection of unprocessed items, which can include text numbers, images audio and video.

Data is raw facts and figures by its self it doesn't provide anything meaningful.

Information: Is processed data. It has meaning and is useful to one or more people.

Information processing cycle

A computer processes input (data) into output (information). Most people refer to the series of input, process, output and storage activities as the information processing cycle.

Ø  Input: this is the first stage in the cycle. This stage involves collection of data from the outside or also from within the system. The commonly used input devices are keyboard, bar code readers, mouse, scanners e.t.c 

Ø  Processing: This is the stage where by the computer works on the data entered and makes it usable.

Ø  Output: this is the stage in which the processed information is now transmitted to the user. The output can be given inform of audio, video, text and graphics. Results can be viewed on the screen or printed on a physical medium.

Ø  Storage: after the data has been processed into information the results can be kept for future use.

How a computer represents data

The computer reads and stores data of all kinds in form of numbers.

Computers use the binary number system while humans normally use decimal number system. 

Binary number system

Ø  Has two distinct digits, 0 and 1

Ø  0 and 1 combine to make numbers.

Decimal number system

Ø  Contains ten distinct digits e.g 0 up to 9.

Ø  Digits combine to make larger numbers.

Digital data representation

The form in which information is conceived manipulated and recorded.

Bit (binary digit)

Ø  It is the smallest possible unit of data a computer can recognize or use.

Ø  In other words, it is the smallest unit of data representation.

0 (off, No) OR 1 (on, Yes).

Byte

Ø  The Smallest unit of data Storage.

Ø  A byte is 8 bits, about one character of data.

Ø  Half a byte is a nibble.

Bits and bytes

Ø  One bit is a single 0 or 1.

Ø  One byte consists of 8 bits.

Ø  One kilobyte consists of 1,024 bytes approximately 1000 bytes.

Ø  One megabyte is 1,024 kilobytes or approximately 1 million bytes.

Ø  One gigabyte is 1,024 megabytes or approximately 1 billion bytes One terabyte is 1,024 gigabytes or approximately 1 trillion bytes.

3. HARDWARE

These comprises of physical, electronic, electric and mechanical components of a computer that help it to process data. They can also be defined as parts / components of a computer that are tangible and occupy space.

These components include input devices, output devices, a system storage devices and communication devices.

Qn: What is the difference between Computer Hardware and Computer Peripherals?

Computer hardware refers to the physical components of a computer that can be touched.

Computer hardware includes the essential mechanical, magnetic, electronic, and electrical components making up acomputer system

While

A peripheral is a device attached to a host computer but not part of it whose primary functionality is to expand the host’s capabilities. A peripheral device is not part of the system's core architecture. The Illustration below shows the most common hardware.

Hardware that is not part of the system unit is sometimes called a peripheral device or device.

3.1. Output devices

This is any type of hardware component that conveys information one or more people.

Commonly used output devices include display devices, printers, speakers and headsets, fax machines and fax modems, multifunction peripheral data projectors e.t.c.

Output is data that has been processed into useful form. The computer processes input (data) into information (Output). 

The out put, which can be easily understood and used by human beings, are of the following two forms:

1.        Hard Copy: The physical form of output is known as hard copy. In general, it refers to the recorded information copied from a computer onto paper. Hard copy output is permanent and a relatively stable form of output. This type of output is also highly portable. Paper is one of the most widely used hard copy output media.

2.        Soft Copy: The electronic version of an output, which usually resides in computer memory and/or on disk, is known as soft copy. Unlike hard copy, soft copy is not a permanent form of output. It is transient (lasting for a short period of time) and is usually displayed on the screen. This kind of output is not tangible, that is, it cannot be touched. Soft copy output includes audio and visual form of output, which is generated using a computer

Following are few of the important output devices, which are used in Computer Systems:

Monitors

Monitor commonly called as Visual Display Unit (VDU) is the main output device of a computer. It forms images from tiny dots, called pixels,that are arranged in a rectangular form. The sharpness of the image depends upon the number of the pixels.

There are two kinds of viewing screen used for monitors:

Ø  Cathode-Ray Tube (CRT). In the CRT, display is made up of small picture elements called pixels for short. The smaller the pixels, the better the image clarity or resolution. It takes more than one illuminated pixel to form whole character, such as the letter 'e' in the word help.

Ø  Flat-Panel Display MonitorThe flat-panel display refers to a class of video devices that have reduced volume, weight and power requirement compared to the CRT. You can hang them on walls or wear them on your wrists. Current uses for flat-panel displays include calculators, video games, monitors, laptop computer, graphics display.The flat-panel display are divided into two categories:

1.        Emissive Displays - The emissive displays are devices that convert electrical energy into light.

Example are plasma panel and LED (Light-Emitting Diodes).

2.        Non-Emissive Displays - The Non-emissive displays use optical effects to convert sunlight or light from some other source into graphics patterns. Example is LCD (Liquid-Crystal Device)

Printers.

A printer prints information and data from the computer onto a paper. The quality of a printer is determined by the clarity of a print it can produce, that is, its resolution.

Printers are divided into two basic categories: impact printers and non-impact printers. As their names specify, impact printers work by physically striking a head or needle against an ink ribbon to make a mark on the paper. This includes dot matrix printers, daisy wheel printers, and drum printers. In contrast, inkjet and laser printers are non-impact printers. They use techniques other than physically striking the page to transfer ink onto the page.

Factors considered before buying a printer

Ø  The number of pages per minute (ppm) the printer can print.

Ø  The memory size of the printer i.e. at least 2 MB Ø The price of the cartridge or tonner.

Ø  The availability of cartridge or tonner.

Ø  The price of the printer.

Ø  The purpose for which the printer is going to be put to use

Advantages of Hard copy over soft copy

Ø  A hard copy can easily be accessed by both the rich and poor readers.

Ø  It cannot easily be changed without tracing.

Ø  It can be read off-line namely without a computer.

Ø  It is cheaper compared to softcopy, which requires computer devices to be able to read the information / data.

Ø  Hard copies last longer if stored in a safe place compared to softcopy, which must be all the time changed with the technological developments taking place.

Speakers and headsets

An audio output device is a component of a computer that | produces music, speech, or other sounds such as beeps. Two commonly used audio output devices are speakers and headsets. Many personal computers users add stereo speakers to their computers to generate a high-quality sound.

Fax machines and Fax Modems

A fax machine is a device that transmits and receives documents over telephone lines. A fax modem is a modem that allows you to send (and sometime receive) electronic documents as faxes

Data projectors

These are devices that take the images from a computer screen and projects it onto a larger screen and projects it onto a larger screen so an audience of people can see the image clearly.

Qn1: Mention devices which can be classified as both input and also output computer hardware.

1.        Touch Screen - a touch-sensitive display device you touch words, pictures, numbers, letters, or locations identified on the screen.

2.        a floppy diskette drive - a device used for both reading and writing data to and from a floppy disk

3.        Optical Disk Writer - a device used for both reading and writing data to and from optical disks such as CDs, DVDs and Blu-ray disks

4.        a hard disk drive - a device used for both reading and writing data to and from a Hard disk

5.        USB flash drive - used for both reading and writing data to and from Flash disks

6.        Modem

3.2. Input devices

An input device is any hardware component that allows you to enter data or instructions into the computer Six widely used input devices are the keyboard, mouse, microphone, scanner, digital camera and PC video camera.

Mouse. Is a pointing device used to manipulate on screen objects. A mouse is a small hand held device used for pointing.

A mouse moves a pointer on the computer screen.

It acts like a finger, allowing you to press buttons and select objects

Using your mouse

Basic parts

A mouse typically has two buttons: a primary button (usually the left button) and a secondary button (usually the right button). The primary button is the one you will use most often. Most mice also include a scroll wheel between the buttons to help you scroll through documents and web pages more easily. On some mice, the scroll wheel can be pressed to act as a third button. Advanced mice might have additional buttons that can perform other functions.

Ø  Left Hand Button - Use to point and select 

Ø  Right Hand Button - To open menus, commands

Ø  Using the scroll wheel

Ø  If your mouse has a scroll wheel, you can use it to scroll through documents and web pages. To scroll down, roll the wheel backward (toward you). To scroll up, roll the wheel forward (away from you).

Ø  Cord - plugs mouse into computer

Mouse operations Pointing

Pointing to an item on the screen means moving your mouse so the pointer appears to be touching the item.

When you point to something, a small box often appears that describes the item.

Ø  Clicking (single-clicking). To click an item, point to the item on the screen, and then press and release the primary button (usually the left button). Clicking is most often used to select (mark) an item or open a menu. This is sometimes called single-clicking or leftclicking.Right click to open a menu and to give more advanced instructions

Ø  Double-clicking. To double-click an item, point to the item on the screen, and then click twice quickly. If the two clicks are spaced too far apart, they might be interpreted as two individual clicks rather than as one double-click.Double-clicking is most often used to open items on your desktop. For example, you can start a program or open a folder by double-clicking its icon on the desktop.

Ø  Drag. You can move items around your screen by dragging them. To drag an object, point to the object on the screen, press and hold the primary button, move the object to a new location, and then release the primary button.Dragging (sometimes called dragging and dropping) is most often used to move files and folders to a different location and to move windows and icons around on your screen.

Tips for using your mouse safely.

Holding and moving your mouse properly can help you avoid soreness or injury to your wrists, hands, and arms, particularly if you use your computer for long periods of time. Here are some tips to help you avoid problems:

Ø  Place your mouse at elbow level. Your upper arms should fall relaxed at your sides.

Ø  Don't squeeze or grip your mouse tightly. Hold it lightly.

Ø  Move the mouse by pivoting your arm at your elbow. Avoid bending your wrist up, down, or to the sides.

Ø  Use a light touch when clicking a mouse button.

Ø  Keep your fingers relaxed. Don't allow them to hover just above the buttons.

Ø  When you don't need to use the mouse, don't hold it.

Ø  Take short breaks from computer use every 15 to 20 minutes 

Other pointing devices / variants of the mouse

The mouse is the most widely used pointing device today. Some users however, work with other pointing devices.

These include the following.

Ø  Track ball. A track ball is a stationary pointing device with a ball onto its top.

Ø  Touchpad. A touchpad is a small, flat, rectangular pointing device that is sensitive to pressure and motion. To move the pointer using a touchpad, slide your fingertip across the surface of a pad.

Ø  Joystick and wheel. A joy stick is a vertical lever mounted on a base. You move the lever in different directions to control the actions of the simulated vehicle or players Ø Wheel. Is a steering wheel-type input device.

Ø  Pointer stick. A pointer stick is a pressure-sensitive pointing device shaped like a. pencil eraser that is positioned between keys on a keyboard.

Ø  Light pen. A light pen is a handheld input device that can detect the presence of light.

Ø  Touch screen. A touch user's screen is a touch-sensitive display device. Users interact with these devices by touching areas of the screens require a lot of arm movements.

Keyboard

A keyboard is an input device that contains keys users press to enter data into a computer.

This is an input device comprising of alphabetical letters, numbers and other keys used to enter data into a computer. Many computer keyboards have got four sections.

Ø  Typing keys (Alphabetical key pad): Which include letters of the alphabet, numbers, punctuation marks, and other basic keys.

Ø  Numeric key pad: on the right side of the keyboard.

Ø  Functional Keys: which are labeled with the letter F followed by a number (Fl, F2 F12)

Ø Special keys on the keyboard

1.        Enter Key (Execute key). It is used to accept a command or execute a command. Or it is used to go to another line when typing,

2.        Back space key. It is used to erase / rub characters to the left side of the cursor.

3.        Space bar. It is the longest key on the keyboard and it is used to insert spaces between word and characters.

4.        Caps lock. It is used to turn capital letters into small letters and small letters into capital letters. When the caps lock is pressed a caps lock light on the top right corner is turned on to indicate that you are in capital letters to switch to small letters press the caps lock button again,

5.        Shift key. It is used to activate characters on top of the buttons, it can also turn in either small letters or capital letters dependin g on the keyboard case mode.

6.        Delete key. It is used to erase characters on the right side of the cursor.

7.        Fl: It is used as help.

8.        Esc (escape): it is used to cancel an application under taken.

Functions of the keyboard.

Its keys allow the user to type data in form of text.

It can be used to command the computer to perform an operation or task,

It is the major connector between the user and the computer,

Without it die user may not be put in the language the compute understands,

Other input devices

Scanner. This is a light-sensing input device that reads printed text and graphics and translates the results into a form a computer can process

Digital camera. It allows users to take pictures and store the photographed images digitally Instead of on traditional film.

Web cam. This is a video camera that displays it's output on a web page.

Joysticks. It is a pointing device with vertical lever for playing games.

Touch Screen. A touch screen is a special kind of input device that allows the direct selection of a menu item or the desired icon with the touch of finger. Essentially, it registers the input when a finger or other object is touched to the screen

Bar code reader. Bar code is a machine-readable code in the form of a pattern of parallel vertical lines of varying widths. It is commonly used for labeling goods that are available in super markets and numbering books in libraries. This code is sensed and read by a bar code reader using reflective light. The information recorded in bar code reader is then fed into the computer, which recognizes the information from the thickness and spacing of bars.

4. SOFTWARE

Software is a set of instructions that drive a computer to perform specific tasks.

These instructions tell the machine’s physical components what to do.

A set of instructions is often called a program.

When a computer is using a particular program, it is said to be running or executing the program.

4.1. Application oftware

It consists of programs that perform specific tasks to a user. Application software is used for a variety of reasons.

•      As a business tool.

•      To assist with graphics and multimedia projects

•      To support home, personal, and educational activities.

•      To facilitate communication

Most application software are available as packed software that can be purchased in a software shop or the web. Application software is available of forms. i.e. packages (off-shelf) custom, shareware, freeware and public domain.

Packaged software (off-shelf)

This is a mass produced, copy written retail software that meets the needs of wide variety of users not just a single user or company. Application software are available in general nature 

Custom software

These are software designed to meet the needs of a particular organization or user (consumer) and performs function specific for the business or industry. Sometimes the company cannot find package software that meets its requirement so it orders for a custom software

Shareware

This is a copy written software that it is distributed free for a trial period

To use a share ware program beyond that period you send the payment to the person or a company that developed that program

Free ware

This software is provided at no cost to a user by an individual or a company Public ware

Is an application software that is designed for the public.

Starting and interacting with an application software To use application software you must instruct the operating system to start the program

4.2. Types of software

Computer software is broadly divided into two categories namely:

•      System software

•      Application software System Software.

This consists of programs that control or manage the operation of the computer and its devices. System software serves as an interface between users, the application its software and the computer's hard ware. System software is computer software designed to operate the computer hardware and to provide maintain a platform for running application software. Examples of system software include;

•      The operating system

•      Utility Programs

•      Programming language

OPERATING SYSTEM

This is a set of programs containing instructions that co-ordinate all the activities among hardware resources.

•      In otherwords, an operating system is a computer’s master control program.

•      It provides a user with the tools (commands) that enable him/her interact with the computer.

•      It also acts as a primary controlling mechanism for the computers hardware.

•      Without an operating system, a user cannot run an application program on their computer. Classification of operating system Real-Time operating Systems:

•      Refers to multitasking operating system that aims at executing real-time applications.

•      A real time application is an application that responds to certain inputs extremely quickly.

•      Very fast and relatively small operating systems.

•      Built into a device, not loaded from a disk drive.

•      Used in MP3 players, Medical devices such as medical diagnostics equipment, life-support systems etc.       

Single-User/Single-Tasking Operating Systems:

•      Allows a single user to perform just one task at a time

•      Take up little space on disk

•      Run on inexpensive computers

•      Examples include; MS-DOS and Palm OS for palm handheld computers.

Single-User/Multi-Tasking Operating Systems:

•      Allows a single user to perform two or more functions at once.

•      Commonly used on personal computers.

•      Examples include; Microsoft Windows and MAC OS.

Multi-User/Multitasking Operating Systems:

•      Allows multiple users to use programs that are simultaneously running on a single network server.

•      Here, each user is given a user session on the server.

•      UNIX, Linux are examples.

•      Maintenance can be easy.

•      Requires a powerful computer.

FUNCTIONS OF OPERATING SYSTEM

•      The operating system manages the computer devices (Device manager)

•      It conducts the process of booting or starting the computer (starting a computer)

•      It acts as a file manager (file management):Operating systems often provide users with the capability of managing files, viewing graphics files, uninstalling programs, scanning disks.

•      It acts as an interface between the computer and the user(providing a User interface)

•      It provides the means for proper user of the resources like monitor, memory, input and output devices,

•      It interprets the program instructions one at a time (managing programs):

•      Some operating systems support only one running program at a time others support thousands of users running multiple programs.

•      It loads the user program into the memory.

•      It gives instruction to display the results on the monitor.