INTRODUCTION TO COMPUTERS 1

Computer Tutorials for Beginners

Before we can fully grasp the idea and whole concept of ICT we must first fully understand the meaning of each word ICT.

ICT is an abbreviation of Information Communication Technology. In every career or job you choose, you will be someway somehow be affected by ICT because our World nowadays are made up of IT devices and stuffs.

The Effective use of ICT and devices can affect you positively or negatively. Whereas ICT and its tools help organizations, institutions, agencies, people positively, others to the other way round.

•INFORMATION

A message received and understood.

Knowledge acquired through study, experience or instruction.

A collection of facts from which conclusions may be drawn.

•COMMUNICATION

The activity of communicating; the activity of conveying information.

Something that is communicated by or to or between people or groups.

A connection allowing access between persons or places.

•TECHNOLOGY

The practical application of science to commerce or industry.

The discipline dealing with the art or science of applying scientific knowledge to practical problems.

DEFINITION OF ICT

•Information Communication and Technology is computing and communications facilities and

features that support everyday life.

•Information Communication Technology is the study of collection of facts which is communicated

between two entities which supports or aids in the creation and manipulation of Information and

Communication.

ICTs

ICTs are the technologies that communicates information. It facilitates the communication.

INFORMATION PROCESSING CYCLE

Information processing is any computer process that changes data into information.

Information processing cycle is defined as the series of input, process, output and storage activities

of the computer.

As the output of information processing may also be the input of a later process, the process is said
to be a cycle.

There are four stages in Information Processing Cycle

Input  ------------   Input Devices (keyboard, Mouse etc.)

Processing --------------- CPU(Central Processing Unit) also known as the brain of the Computer.

Output  ---------------  Output Devices (Monitor, Printer etc.)

TYPES OF COMPUTERS

Digital Computer is a computer which communicate or operate in binary mode. Eg;

•Super Computers - These are the most powerful computers, they are special, high-capacity

computers used by organizations, agencies.

•Mainframe Computers – They are large computers occupying wire and air-conditioned

rooms. They are capable of great processing speeds and data storage and can handle millions

of transactions at the same time.

•Mini Computers – These computers are sometimes referred to as mid-range computers because

they are desk-size and fall between the abilities of mainframe computers and

microcomputers. They are sometimes used as servers in organizations which connect  and

controls the activity of several minicomputers.

•Workstations – They are powerful single-user computers, they are used for tasks that require a

great deal of power such as product design and computer animations.

•Personal Computers (PCs)- They are more commonly known as personal computers. The Term

PC is applied to IBM users or compatible computers and are also desk size.

Analogue Computer is a computer which operate or communicate using physical quantity

received from continuous varying variables. Eg;

•Speedometer

•Thermometer

•Hydrometer

Hybrid Computers

A hybrid computer is a computer which combines both the features of digital and analogue computers. Eg; ATM, Money Counting Machine etc...

•Every Computer is a system.A system is a group of related or interconnected components in

an organized manner which accept input, processing the input into output to achieve a goal.

•There are basically three component of a system.

  Input   ------------> Processing  -----------> Output

PERSONAL COMPUTERS

Simply a computer is an electronic system which accept data as input, process that data and give out an information.

There are two type of personal computers

•Desktop PC

•Laptop 

Desktop Computers

They are computers as which is design to sit on top of a desk. They are small but heavy to

carry around. There are two major kinds

1.Desktop Computer; one which sits horizontally on the desk.

2.Tower Computer; one which stands vertically on the desk.

Laptop Computers

They may be either battery powered or AC-powered. As the name seeks to explain,these

computers are designed to rest on the lap of the user. They are open and a close as you

would open a book.

Computer Components

Any kind of computers consists of HARDWARE AND SOFTWARE.  

Hardware: Computer hardware is the collection of physical elements that constitutes

computer system. 

Computer hardware refers to the physical parts or components of a computer such as the

monitor, mouse, keyboard, computer data storage, hard drive disk (HDD), system unit

(graphic cards, sound cards, memory, motherboard and chips), etc. all of which are

physical objects that can be touched.

Input Devices  

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance. Input device Translate data from form that humans understand to

one that the computer can work with. Most common are keyboard and mouse .

Example of Input Devices:- 

1. Keyboard 2. Mouse (pointing device) 3. Microphone 4. Touch screen 

5. Scanner 6. Webcam 7. Touchpads 8. MIDI keyboard 9.  10. Graphics Tablets 

11. Cameras 12. Pen Input 13. Video Capture Hardware 14. Microphone 15. Trackballs 

16. Barcode reader 17. Digital camera 18. Joystick 19. Gamepad 20. Electronic

Whiteboard.

Note: The most common use keyboard is the QWERTY keyboard. Generally standard Keyboard has 104 keys.   

Central Processing Unit (CPU) :  A CPU is brain of a computer. It is responsible for all

functions and processes. Regarding computing power, the CPU is the most

important element of a computer system.   

The CPU is comprised of three main parts : 

* Arithmetic Logic Unit (ALU): Executes all arithmetic and logical operations.

Arithmetic calculations like as addition, subtraction, multiplication and division.

Logical operation like compare numbers, letters, or special characters .

* Control Unit (CU):  controls and co-ordinates computer components. 

1. Read the code for the next instruction to be executed.

 2. Increment the program counter so it points to the next instruction.

 3. Read whatever data the instruction requires from cells in memory.

 4. Provide the necessary data to an ALU or register. 

5. If the instruction requires an ALU or specialized hardware to complete, instruct the

hardware to perform the requested operation. 

* Registers :Stores the data that is to be executed next, "very fast storage area".  

Primary Memory:- 

1. RAM: Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis, so that it can be promptly

accessed by the processor as and when needed. It is volatile in nature, which means

that data will be erased once supply to the storage device is turned off. RAM stores

data randomly and the processor accesses these data randomly from the RAM

storage. RAM is considered "random access" because you can access any memory cell

directly if you know the row and column that intersect at that cell.

 2. ROM (Read Only Memory): ROM is a permanent form of storage. ROM stays

active regardless of whether power supply to it is turned on or off. ROM devices do

not allow data stored on them to be modified.  

Secondary Memory:-  Stores data and programs permanently  :its retained after the

power is turned off. 

1. Hard drive (HD): A hard disk is part of a unit, often called a "disk drive," "hard

drive," or "hard disk drive," that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces.

2. Optical Disk: an optical disc drive (ODD) is a disk drive that uses laser light as part 

of the process of reading or writing data to or from optical discs. Some drives

can only read from discs, but recent drives are commonly both readers and recorders,

also called burners or writers.

Compact discs, DVDs, and Blu-ray discs are common types of optical media which can 

be read and recorded by such drives. Optical drive is the generic name; drives are 

usually described as "CD" "DVD", or "Bluray", followed by "drive", "writer", etc. There 

are three main types of optical media: CD, DVD, and Blu-ray disc. CDs can store up to 

700 megabytes (MB) of data and DVDs can store up to 8.4 GB of data. Blu-ray discs, 

which are the newest type of optical media, can store up to 50 GB of data. This 

storage capacity is a clear advantage over the floppy disk storage media (a magnetic 

media), which only has a capacity of 1.44 MB. 

3. Flash Disk A storage module made of flash memory chips. A Flash disks have no

mechanical platters or access arms, but the term "disk" is used because the data are

accessed as if they were on a hard drive. The disk storage structure is emulated. 

COMPARISON BETWEEN RAM AND HARD DISK DRIVE

Key Differences

• All data you stored on hard disk are permanently saved during usage and after shutdown. While RAM keeps memory until system is running. All the memory will be erased automatically after your system switched off.
• Currently, RAM are available from 256MB to 8GB (recently announced by Seagate). While hard disk size starts where RAM size ends. 10GB to 8TB size hard disk are available in the market.
• RAM is just a chip containing some circuits. Hard disk is almost a machine having multiple parts like platters, plastic disc, magnate, writer & reader bar.
• If you are running short of hard disk space, you can use external hard disk for your data storage. There is no option for external removable RAM.
• Whenever we perform some task, memory first comes from RAM instead of hard disk. Hard disk is a secondary mean for circulation of memory.
• RAM works faster than hard drive. Basic purpose of RAM is to fast the performance of system. If you have low RAM, your system speed will be low. Main purpose of hard disk is to store information. If you have low capacity hard disk there will be less impact on your system speed.

Output devices : An output device is any piece of computer hardware equipment used 

to communicate the results of data processing carried out by an information processing 

system (such as a computer) which converts the electronically generated information

into human readable form. 

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Exmple on Output Devices: 

1. Monitor 2. LCD Projection Panels 3. Printers (all types) 

4. Computer Output Microfilm (COM) 5. Plotters 6. Speaker(s) 7. Projector   

Note Basic types of monitors are
A.Cathode Ray Tube (CRT).
B. Liquid Crystal Displays(LCD). C.light-emitting diode (LED). Printer types: 1-Laser Printer. 2-Ink Jet Printer. 3.Dot Matrix Printer   

 Software 

Software is a generic term for organized collections of computer data and

instructions, often broken into two major categories: system software that provides

the basic non task-specific functions of the computer, and application software which

is used by users to accomplish specific tasks.   

Software Types

A. System software is responsible for controlling, integrating, and

managing the individual hardware components of a computer system so that other

software and the users of the system see it as a functional unit without having to be

concerned with the low-level details such as transferring data from memory to disk,

or rendering text onto a display.

 Generally, system software consists of an operating system and some fundamental

utilities such as disk formatters, file managers, display managers, text editors, user

authentication (login) and management tools, and networking and device control

software. 

 B. Application software is used to accomplish specific tasks other than just running

the computer system.

Application software may consist of a single program, such as an image viewer; a

small collection of programs (often called a software package) that work closely

together to accomplish a task, such as a spreadsheet or text processing system; a

larger collection (often called a software suite) of related but independent programs

and packages that have a common user interface or shared data format, such as

Microsoft Office, which consists of closely integrated word processor, spreadsheet,

database, etc.; or a software system, such as a database management system, which

is a collection of fundamental programs that may provide some service to a variety of

other independent applications.