THEORY OF COMPUTER

A computer is an electronics device that manipulates data or information. It has the ability to store, retrieve, send email and browse the internet. You can also use computer to handle spreadsheet, accounting, database management, presentation, games and more.
The first electronic computer was called Electronic Numerical Integrator and Computer (ENIAC). It was developed in 1946. It took up 1,800 square feet and weighed 30 tons.

TYPES OF COMPUTERS
Computer is of many types, you use computer when you operate with the ATM machine to withdraw money, when you use calculators you are using a type of computer.

There are Desktop computers:- these computers are used in the schools, homes, offices or places of work, library and more. They can be small, medium, or large. They usually sit on the desk. Once a mouse, keyboard, monitor are connected to it, it becomes a desktop computer. It allows for upgrading of new wares.

Laptop computer:- this is another type of computer that you may be familiar with. They are portable and can be powered by a battery or AC. It is usually very to upgrade and it is sometimes called a notebook computer.

Tablet computers:- these use a touch sensitive screen for typing and navigation. They do not require keyboard or mouse and they are more portable. E.g. is an Ipad.

Mobile phones:- many mobile phones can do a lot of things that a computer can do such as browsing the internet or playing games. They are popularly called Smartphone.

Game consoles:-this is a specialized type of computer that is used for playing video games. Although they are not fully as a computer but they can have the ability to browse the internet.
Tv (Television):- some television now have computing abilities, they can be used to vies your facebook news feeds, watch streaming on the internet. Eg of such television is Netflix.

USES OF COMPUTER
Computer can be used in so many ways:-
In the office for recording or keeping of data.
At home for entertainment
Can be used for calculation
Can be used for movie editing and recording
Can be used in the military and security purposes
For weather forecasting
For playing games
For teaching or education
For browsing the internet
For publication or in the book press
Can be used in the banks for accounting
Used for surveying and measurement
Used in the medical field.
And so much more other areas that we cannot list here.
ATTRIBUTES OF COMPUTERS.

ACCURACY: -computers do not produce wrong result unless if wrong input was entered or there is virus interference.

SPEED: -computers are very fast machines in operation. They can work on large load of commands and produce result quickly.

VERSATILITY: -they are very versatile in nature, can work in any field and aspect of life.

EFFICIENT: -they are very organized machines; they are competence and produce result based on precision.

STORAGE: -computers have very large storage capacity for keeping of data for future reference.

COMPUTER IS MADE OF TWO PARTS.

THE HARDWARE AND THE SOFTWARE.
The Hardware is any part of the computer that has physical structure such as the monitor, keyboard, mouse, speaker and more. They can be seen, felt and touched.

The Software is any part of the computer than is made of set of instructions and commands that help the hardware to function. The software tells the hardware what to do. It is what guides the hardware and tells it how to accomplish a task. Some examples of software are Web browsers, games, word processor and more.

SOME OF THE COMPUTER HARDWARE COMPONENTS

Keyboard: - this is a computer hardware that is used to type in letter, numbers, symbols, sign etc into the computer.

Mouse: - this is another hardware that can be used to issue commands to the computer.

Joystick: - this is a hardware that is commonly found and used for playing computer games.

Microphone: - this is a hardware that can be used to record sound into the computer.

Scanner:- this can be used to capture images, documents and more into the computer.

Printer:- this is used to bring out the hardcopy of a document or image.

Monitor:- this is a hardware that helps to show data and processes of computer operation to the computer user.

Computer speaker: - this is a hardware that helps to produce sound out from a computer when you play music or watch videos.

Hard disk: - this is the primary storage device of the computer; it is where files and programs are saved.

Diskette: - this is another storage device that is small in capacity. It is removable and usually 1.44MB in capacity and 3.5 inches in size.

Ram: - this is a computer memory device that holds data temporally as the computer processes it. It is volatile in nature viz it looses its contents when the computer is turned off.

Rom: - this is another computer memory device that has more retentive capacity than the Ram. The Rom can hold data longer than the Ram.

Micro processor: - this is the brain of the computer. It processes instructions or commands and does the control and logical sequence and arithmetic.

CD-ROM DRIVE: - This device allows you to read data from a disk; it can also be us to write data into an empty disk for storage purposes.
There are more other computer hard wares that we may not list here.

SOME OF THE COMPUTER SOFTWARE COMPONENTS.
Three are two types of computer software:-

THE SYSTEM SOFTWARES AND
THE APPLICATION SIFTWARES

THE SYSTEM SOFTWARES: - The system software is the operating system software. It provides a user interface for users to manage files, start a program, and customize computer settings and more. E.g. Windows Operating System. Which has these as examples, Windows 95, 98, 2000, windows Xp, Vista, Windows Me and Windows 32 and more? They are the foundation of computer software.

THE APPLICATION SIFTWARES: - the application softwares are created for specific purposes or another. They come in different purposes and functionalities eg. Microsoft word, Microsoft Excel (spreadsheet), Microsoft Access (database management), Oracle, Microsoft PowerPoint (presentation or persuasion), internet browser like internet explorer, Mozilla Firefox, games and more.

CLASSIFICATIONS OF COMPUTERS
There are some classifications of computers based on some categories. These classifications are meant to enhance your knowledge about computer existence and changes over the years.
We have four classifications of computer and they are:-

CLASSIFICATION BASED ON AGE
CLASSIFICATION BASED ON SIZE
CLASSIFICATION BASED ON PURPOSE
CLASSIFCTAION BASED ON MODE OF OPERATIOIN.
CLASSIFICATION BASED ON AGE.

First Generation computers: - these computers use Vacuum tubes to operate. They are the earliest of computers and they are usually large and produce a lot of heat, consume a lot of electricity. They are costly and can support thousands of users at a time.

Second Generation: - these computers use Transistors to operate. They share most of what the first generation has but the focus was on reduction in size of computers. The size was reduced and heat generation, electric consumption, size and cost were minimized but it was still powerful.

Third Generation computer: - these computers used Integrated Circuit with multiple transistors to perform.

Fourth Generation computers: - these computers used large-scale integration with silicon chips.

Fifth Generation computers: - these computers used microprocessor, a tiny processing unit called

CPU. They ushered in the era of microcomputers that catapulted computers into smaller sizes.

CLASIFICATION OF COMPUTER BASED ON SIZE.

Under this category, computers are classified based on their sizes.
We have:-

SUPER COMPUTERS: - these computers were very large, took up large space with very high electric consumption generated a lot of heat and they were costly. However, these computers were very powerful, they could support thousands of people at a time, and they have very fast processing speed and can perform millions of calculations at short time. They have very large storage capacity.

MAINFRAME COMPUTERS: -these computers followed the super computers and they were also large but smaller than super computers. They shared most of what can be attributed to super computers in smaller rate. They were cheaper than super computers.

MINI COMPUTERS: -they are powerful computers that have very large capacity and became easily accessed by companies and organizations of repute. They shared attributes of mainframe computers but consume lesser electricity and are cheaper than mainframe computers.

MICRO COMPUTERS: - these are what can be referred to as Personal computers. They are very smaller than the above computers and can be purchased by individuals and offices. They are commercialized and have limited speed and storage capacity. They are found in the offices and at homes and school. Usually kept on the desk and are also known as Desktop computers. They use micro processor.

LAPTOPS: - these are very portable computers that can be carried about. They are also known a s Notebook due to their small size. They have speed and storage capacity. They can process data at faster rate but they are costly and are hardly upgradable. They have their monitor fixed together with the system unit and they don’t generate much heat.

PDA, AND PHONES. These are very small devices that function as computers. They have most of what computer is known with and they are portable. Phones that have these capabilities are called Smartphone.

CLASSIFICATION BASED ON PURPOSE.
Some computers are built for specific purpose and as such are meant to solely for such purpose. E.g. are computers built for weather forecasting, computers built for space exploration, ATM Machine etc.

CLASSIFIFCATION BASED ON MODE OF OPERATION.
Some computers are categorize based on their mode of operation, how they perfom action or execute commands. We have:-

ANALOGUE COMPUTERS
DIGITAL COMPUTERS
HYBRID COMPUTERS.

Analogue Computers:- these use continuous variables (physical quantities) to process data. An example of such computers are WALL CLOCK that uses long hand and short hand to symbolize time, thermometer that use liquid quantity to show measures, rain gage, wind gage, car speedometer etc. they are more or less accurate in operation.

DIGITAL COMPUTERS: -these computers use discrete numbers; discrete numbers are identifiable or separate numbers that can be easily figured out e.g 1 and 0. Examples of Digital computer are wristwatch, laptops and phones. They are always fast in operation.

HYBRID COMPUTERS:-these computers have the capabilities of Analogue and Digital computers. They are fast and accurate in nature. Modern laptops and cars are good examples.

INPUT AND OUTPUT, INPUT DEVICE AND OUTPUT DEVICE.

SOME COMMON ERORS
There is difference between input and input device.

INPUT: -An input can be a command, instruction, data entered into the computer through various input devices. E.g. A sound which entered into the computer through a microphone is an input, alphabets and numbers, signs and symbols, pictures and videos, commands and instructions, waves etc are inputs types of inputs that can be entered into a computer through various input devices. Inputs are soft in nature.

INPUT DEVICE: -an input device is a hardware that helps to enter inputs into the computer. Eg. Are scanners that scan images into the computer, microphone that conveys sounds into the computer, keyboard that helps type data into the computer, mouse that help issue instruction or commands into the computer, joysticks, trackball, game pads etc. these are common input devices. Input devices are commonly hard in nature.
There is difference between output and output device.

OUTPUT:-an output can be a finished result of a computer processing operation. They are the end result of (IPC) Information PROCESSING Circle. Examples of some outputs are sounds produces by a speaker, alphabets or data on the screen produced by the monitor, printed copy of a book produced by the printer etc. an output is produced through an output device and they can be both soft and hard in nature.

OUTPUT DEVICE:-this can be a computer device that help to produce the finished result of (IPC). Eg, the printer that prints, the speaker that produces sounds, the monitor that shows data on the screen. Output devices are commonly hard in nature.

COMMON ABBREVIATIONS.

CPU:Central Processing Unit
SU:-System Unit
VDU:-Visual Display Unit
GUI:-Graphical User Interface
PC:-Personal Computer(s)
CD:-Compact Disc. Etc.
USB:-Universal Serial Bus

PARTS OF THE CPU

The CPU is made up of three parts:-

The Control Unit:-this part of the CPU controls the functions of the computer, the utility programs and accepts new computer application during installation.

ALU (Arithmetic Logic Unit):-this part takes care of the calculations of math, statistical and logical sequences of the CPU.
Bank of Register:-the bank of Register records commands that will be executed next and sort records in order.

COMPUTER MONITOR

A computer monitor is the Visual Display Unit (VDU). This is an electronic device that transmits information from the computer to the screen thereby acting as an interface that connects the computer with its users. It resembles a Television set. The Monitor is not the computer but the display unit.

TYPES OF MONITORS

There are two types of monitor:-

CRT (Cthode Ray Tube). This uses streams of high-energy electrons to form image on a florescent tube or screen. It is like the Television screen.

ADVANTAGES

CRT is reliable and cost effective (cheap)

DISADVANTAGES

Normally large, produce heat through radiation, consumes electricity.

LCD (Liquid Crystal Display or Diode):-this uses layers of monochrome colors of pixels arranged schematically to form images. Eg, plasma monitors.

ADVANTAGE

Consumes little electricity, light weight, does not occupy much space, can be used with battery or plugged to AC, produce good images at straight view.

DISADVANTAGES

Very costly, poor images at side view.

However, monitors can be equally categorized into
Monochrome (black and white)
Colored (multiple colours).

THE COMPUTER MOUSE

This is a handheld input device that resembles a mouse (rat). It is a hardware that can issue commands, point to an object on the screen or select and drag items.
A mouse has varied number of buttons on it. Some would have two buttons while some would have three buttons. The two buttons are the left and the right buttons. The left button is used to select object while the right button is used to initiate option. Then the third button (middle) is called the scroll button, it is used to scroll and move the pointer up and down the computer screen.
Under the mouse, we find the mouse eye. The mouse eye is a ball fitted under the mouse and it rolls around when the mouse is moved in order to direct the pointer on the screen. So the mouse eye directs the mouse pointer.
The mouse can be differentiated by the type of cord it uses. Some mice (especially old one) use serial cord which is connected to a serial ports on the computer while some mice use USB (Universal Serial Bus) which are connected to a USB port of a computer.

TYPES OF MOUSE

We have Mechanical mouse and Optical Mouse.
The mechanical mouse uses the mouse eye which is under the mouse to control the movement of the pointer on the screen. It is an old form of mouse, it requires a mouse pad to function very well, it is relatively cheaper but it lacks beauty and modern style of technology. Most of mechanical mouse use the serial cord and most of them do not have he scroll button.

OPTICAL MOUSE

The Optical mouse is an modern type of mouse that uses a light beams which is under the mouse to control the movements of he pointer . The light beam replaces the mouse eye. Optical mouse is more sensitive, It is more convenient to use. It normally uses the USB cord and has a scroll button for moving up and down the screen.
It is relatively costlier than mechanical mouse but it does not require a mouse pad to perform well.
A mouse pad is a smooth material that are placed under the mouse to achieve smoothness and also to protect the mouse eye from possible damage on a rough surface.

^Good stuff!

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