INTRODUCTION TO COMPUTER
Computer is an electronic device that accepts data; manipulate data, store data and change data into information.
Computer can also be defined as a programmed machine that manipulates symbols.

ACTIVITIES OF COMPUTER
The computer system is design to carry out only four activities.

Input operation
Output operation
Processing operation
Storage operation

Input operation
Input is incorporation or entering of data, command and instruction into the computer system.

Processing operation
It’s the manipulation of data to yield the desire result.

Storage operation
It’s the saving of information for future reference.

Output operation
It’s the bringing out of data/information processed by the computer system.

COMPONENT OF THE COMPUTER SYSTEM
Monitor
Keyboard
Mouse
System unit
CPU/processor
Hard disk
Disc drive
Memories
Main-board/motherboard
Signal cable
Power cable
Data cable
BIOS/ROM
CMOS
Co-processor
Cooling fan
Heat-sink
Power supply unit
Integrate peripherals
Floppy disk

USES OF COMPUTER
The use of computer cannot be over emphasized. They are used in all human Endeavors.
Some common uses of computer are:
Communication
Programming
Calculation
Education
Business
Research
Entertainment

CHARACTERISTICS OF COMPUTER
It has a large memory capability, which enables it to store much information.
GIGO: Garbage in, garbage out. I.e. what you give the computer is exactly what the computer will give you back
It works very fast etc.

Assignment
Write five (5) advantages and disadvantage of computer

COMPUTER AREA OF APPLICATION
Most computer teacher/text book miss-comprehends the uses of computer for computer area of application.
Computer area of application simply refers to as the places where computer are use, while the uses of computer simply means what the computer can be used for.
Some computer areas of application are:
Health sector
Aviation sector
Industrial sector
Banking sector
Educational sector etc.

CLASSIFICATION OF COMPUTER
Just as human being may be classified base on color, sex, age etc. computer can also be classified base on some facts:
Classification of computer base on mode or type
Classification of computer base on size
Classification of computer base on generation
Classification of computer base on made or manufacturers
Classification of computer base on purpose.

Classification of computer base on mode or type
This class of computer can be classified base on their mode or type e.g.

Analogue computer
This class of computer process data continuously and output information inform of graph, e.g. speedometers, analogue clock, thermometer etc.

Digital computer
This class of computer works on digit that is from 0s to 1s. Examples are PDA (personal digital assistance) calculator, traffic controller, fuel dispenser etc.

Hybrid computer
These types of computer combine the work of both digital and analogue computers. The digital part serves as regulator and performs logical operation, while the analogue serves as resolver of equations. E.g. the ECG monitor, it takes in an analogue signal that is the heartbeat of the patient and coverts it into the digital format after processing.

Classification of computer base on size
The class of computer can easily be classified base on their sizes e.g.
Micro computer
Mini computer
Mainframe computer
Super computer

Micro computer
As the name implies it’s the smallest type of digital computer, it’s a single user oriented computer e.g. Desktop computer, laptop computer and tower computer etc.

Mini computer
The mini computer is a small, multipurpose and multi task computer. It’s also a multi user oriented computer.
The main differences between microcomputers and minicomputer are:
The mini-computer has large memory capacity than the micro computer
It processes data faster than the minicomputer
It’s bigger than the micro computers

Mainframe computer
The mainframe computers are multi-user and multi-task oriented computer; they are bigger in size and expensive to obtain ECG monitor

Super computer
These are the biggest and most expensive type of digital computer; it is an improvement or enhancement on the mainframe computer.

Classification of computer base on generation
1st generation (1940-1956)
2nd generation (1956-1963)
3rd generation (1964-1970)
4th generation (1971-1989)
5th generation (1999-till date)

First (1st) Generation
This was between the periods of 1940-1956. That was the second (2nd) world war. This generation of computers uses a vacuum tube, it occupies a very large space, consumes lot of energy and it generates lot of heat.

Second (2nd) Generation
This generation was between the periods of 1956-1963. The generation uses transistor; they were small in size but fast in operation. It uses programming language in place of machine language. They were more reliable then the first generation.
Third (3rd) Generation
This generation was between the periods of 1964-1970. The generation uses integrated circuit (IC). It experiences increase in processing speed and accuracy. It leads to the development of operating system. They were smaller, less expensive and more reliable.

Fourth (4th) Generation
This was between the periods of 1971-1989. It leads to the introduction of microprocessor in 1971. They were very small in size with greater capacity and capability. It marks the beginning of microcomputers era; it leads to the greater advancement in the use computer.

Fifth (5th) Generation
This came in 1990s; they became very friendly due to the advancement in the software development. They were faster and more reliable. They possess artificial intelligent making them think like human beings.

Classification of computer base on made or manufacturers
This class of computer can be classified base on their manufacturer examples:
HP computers
LG computers
DELL computers
SAMSUNG computers
PANASONIC computers
TOSHIBA computers
IBM computers

Classification of computer base on purpose
This class of computer can be classified base on their purpose, examples:
General purpose computer
Specific purpose computer

General purpose computer
General purpose computer are types of computer that are design for more than one purpose.

Specific purpose computer
Specific purpose computers are computer specially design for a particular purpose. E.g. fuel dispenser, calculator and wrist watch etc.

COMPUTER PACKAGES
Computer packages are software application program specially design or prepared to perform a certain tasks or job.
E.g.
Microsoft word/word perfect
Lotus 123 Microsoft excel
SPSS (statistical packages)
Card/shop/instant artist/Corel draw
Venture publisher/page maker/Microsoft publisher
Peachtree accounting
Pegasus etc.

WHAT IS INPUT?
Input is incorporation or entering of data, command and instructions into the computer systems.

Input-Devices
Input devices are those devices that are used to incorporate or execute command into the computer system e.g.
Keyboard
Mouse
Joystick
Microphone
Scanner
Digital camera etc.

Keyboard
Keyboard is an input device use to execute command and instruction into the computer system.

Parts of the keyboard
Alpha- numeric keys: – alpha keys are A-Z, numbers keys 0-9
Characters keys e.g.

Mouse
The mouse is an input device, that is use to control the pointer in the GUI and manipulated on-screen object, such as folders, files and icons

Functions of the Mouse
It is use for clicking object
It is use for highlighting text
It is use for drawing
It is use for double clicking (opening files and folders)
It is use for right clicking (demanding for option)

Microphone
Microphone is an input device which converts sound energy into electrical energy for the recording of sound (voice).

WHAT IS OUTPUT?
Output is the bringing out of the content of the computer system; through the means of the output devices.

Output Devices
Output device are devices that bring out the content of the work done on the computer system; e.g.
Monitor
Loudspeaker
Plotter
Printer

MONITOR
Monitor is a non-documented output device that displays the content of the computer system, known as the soft copy. Another name for the monitor is visual display unit (VDU).

Classification of Monitor
Monitor classified into two (2):
Classification of monitor base on color
Classification of monitor base on structure

Classification of Monitor Base on Color
Monochrome monitors
Color monitor

Monochrome Monitor
These type of monitors displays only two colors that is Black and White

Colored monitor
These types of monitors display more than two colors

Classification of Monitor Base on Structure
Top screen monitor
Flat screen monitors

PRINTER
A printer is a documented output device that expresses the coded character on a sheet of paper, otherwise known as hard copy.

Classification of Printers
Classification of printer base on color
Classification of printer base on type and characteristics.

Classification of Printer Base on Color
This class of printer can be classified base on print out color.
Monochrome printer
Color printers

Monochrome Printer
These types of printers print only two colors i.e. Black and White

Color Printer
These types of printer print color document or print out colors

Classification of Printer Base on type and Characteristics.
Impact printer
Non-impact printer

Impact Printer
Impact printers are those types of printers that their element touches paper during printing; e.g. cannon

Non-impact Printer
Non-impact printers are the type of printers that their element doesn’t touch paper during printing.
E.g.
Laser jet
Bubble jet
Ink jet
Desk jet etc.

WHAT IS COMPUTER STORAGE DEVICES?
Computer storage devices are device that are used to store data/information.

Types of Computer Storage Devices
Primary storage devices
Secondary storage devices

Primary Storage Devices
Primary storage devices are the main memories of the computer system. They are: Random Access Memory (RAM) and Read Only Memory (ROM)

Secondary Storage Devices
Secondary storage devices are device that store data permanently in the computer system. E.g.
Hard Disk
Diskette
USB Flash Drive
Compact Disk etc.

Hard Disk
The hard disk is the secondary storage device in the computer system where all data and information are stored. The greater the hard disk capacity, the more data or information it can store.

Diskette
It’s a removable disk that is also used for storing of data and information. It’s up to a dimension of 31/2 and 5.25 inches, the highest data it can store is 1.44 MB.

Flash Drive
The USB flash drive is also a removable disk that can store much more information than diskette. The greater the flash drives capacity, the more data and information it can store.

Compact Disc (CD)
The compact disc is also a storage device that was produce in 1990s in other to enhance the recording of data and information

Types/Uses of Compact Disc (CD)
Audio CD = for music/Audio
VCD: – for graphics
DVD: – for graphics but an improvement on VCD
CD-ROM: – for data and application.

WHAT IS COMPUTER MEMORY?
Computer memory simply refers to the primary storage of the computer system.

Types of Computer Memory
ROM (Read Only Memory)
RAM (Random Access Memory)

ROM (Read Only Memory)
The Read Only Memory otherwise known as the BIOS is a non-volatile memory, in which power failure does not affect it content. It’s read only because it content is configured by the computer manufacturer.

RAM (Random Access Memory)
The Random Access Memory is the working space of the computer system. It’s a volatile memory because power failure affects it content.

DIVISION OF COMPUTERS
Software
Hardware

SOFTWARE
Software is a collection of program that allowed the computer system to perform a specific task or to stop a particular problem. It is a part of the computer that cannot be seen/touch

Types of Software
System Software
Application Software

System Software (Operating System)
System Software is a special program usually writing by the computer manufacturer to coordinate, monitor and oversee all the activities of the computer system. It also contributes to the proper control of the computer system, and enhances the proper performance of the system. Example
Windows
Linux
Unix
Mac Os etc.
Application Software
Application Software is a program design for end-user to perform a specific task or to stop particular problem. They are otherwise known as end-user application. E.g.
Microsoft office
Mavis beacon
Corel draw
VLC player etc.

HARDWARE
Computer hardware simply refers to the physical component of the computer system, that can be seen, touch/carry e.g.
Keyboard
Mouse
Monitor
System Unit
Hard Disk
Ram etc.

THE SYSTEM UNIT
The system unit is the main component of the computer system, which consists of the Motherboard, Power Supply Unit, Cooling Fans, Hard Disk Drives Disc Drive, Memory and other Expansion card etc.

Component of the System Unit
CPU
PSU (Power Supply Unit)
Cooling Fan
Mother Board
CMOS (Complementary Metal-Oxide Semi-Conductor)
Hard Disk
Memories
Disc drive
Cables etc
Central Processing Unit (CPU)
The Central Processing Unit is the heart and brain of the computer system that handle all the processing work.
Component of the CPU
Central Control Unit (CCU)
Arithmetic and Logical Unit (ALU)
Memory Unit (MU)

Central Control Unit (CCU)
It’s the traffic controller part of the central processing unit (CPU). All data, command/instruction flow in and out of the computer passes through the Central Control Unit.

Arithmetic and Logical Unit (ALU)
It’s the component of the CPU that handles the arithmetic and logic operation. A goog example of this operation is: Yes or No, I Accept or I don’t Accept.

POWER SUPPLY UNIT (PSU)
It’s the component of the system unit that regulates and distributes current to all other component in the system unit.

COOLING FAN
The cooling fan is the component of the system unit that keeps the system cool. It’s located very close to the power supply unit (PSU).

MOTHERBOARD
The mother board is the component of the system unit that enhances all other component together critically to the function of the computer system.

CMOS (Complementary Metal-Oxide Semi-Conductor)
The Complementary Metal-Oxide Semi-Conductors (CMOS) otherwise known as the system “battery” is the component of the system unit that retains the system set-up, Date & time when the system is not in use.

Hard Disk Drive
The hard disk drive is the storage location of the computer system that store data and information permanently. Whatever is store in the computer system is in the hard disk drive.

CABLE
Computer cables are insulated wires; use to connect different components of the computer system together.

Types of cables
Data cable
Power cable
Signal cable

Data cable
The data cable is use to connect the hard-disk drive, Disc drive to the motherboard. The cable transmits data only.

Power Cable
The power cable is use to connect the system unit and monitor to the electric socket. The cable transmits current only.

Signal Cable
The signal Cable (VGA) is use to connect the monitor with the system unit. The cable transmits signal only.

COMPUTER VIRUS
Computer viruses are sophisticated self replicating computer programs that automatically install themselves, without the users consent and cause havoc.

Types of Virus
Macro virus
Boot virus
Key loggers
Malware
Trojans horse etc.

COMPUTER MAINTENANCE
Computer maintenance is the way we can adopt to safeguard our computer system. The following are some of the ways to take proper care of our computer system.

1. Position the computer properly
2. Keep the computer in an appropriate environment.
3. Keep the computer in a safe and secured place to avoid theft
4. Avoid liquid and food particles dropping on the system
5. Use clean cloth or dust cleaner to clean the system.
6. Do not sit on any part of the system nor place heavy load on it.
7. Press the key on the keyboard gently when you are using it.
8. Use dust cover to cover the system when it is not in use.
9. Ensure that you put off the computer system properly after use.
10. Unplug the system when it’s not in use.
11. Repair or replace damaged parts of the computer.
12. Protect the computer from too much or low electric power by using uninterrupted power supply
13. Use a password to protect the computer to disallow unauthorized user where you