To define a computer, let us begin with the word ‘compute’ Which means to calculate. We all are familiar with calculations in our day-to-day life. We apply mathematical operations like addition, subtraction, multiplication and division and also many other formulae for calculations. Simple calculations take less time but complex calculations take much longer time. Another factor is accuracy in calculations. So man explored with the idea to develop a machine which can perform this type of arithmetic calculation faster and with full accuracy. This gave birth to a device or machine called computer.
a computer is an electronic device that accepts data, stores data, processes data and outputs results, based on a set of instructions called programme. These instructions tell the machine what to do.
Characteristics of computer: all computers irrespective of their size or type possess common characteristics namely
- Computation: they perform complex activities and arithmetic operations
- programmed: they are programmed to undertake complex, tedious and monotonous tasks
- power: they are very powerful devices
- speed: decalculate at very high speed without making mistakes. The more the power of the computer the more the speed. Supercomputers are faster than microcomputers.
- storage and retrieval of information: a computer can store large amount of data. Computers have main memory and auxiliary memory to aid storage of data. Retrieval of information rates is amazingly unique and fast.
- accuracy: computers have degree of accuracy which prevents false results. However there is room for human error which results in false results. Well wrong data is keyed in by operators it is accepted by the computer and processed. The results will also be wrong and this is called garbage in garbage out(GIGO)
- versatility: computers are extremely versatile. They are capable of performing all tasks provided they are reduced to series of logical steps. They are capable of communicating with one another, receiving and sending data in various forms, such as graphics, texts, sound, video. This ability has led to computer networks, Which is at the heart of the internet and the world wide web (www). Because of the capacity we can send emails and receive the answers within a short period
- automation: did demonstrate incredible automation if correctly programmed. They can complete tasks once initiated without error
- diligence: Computers process information diligently, loyally and obediently. They do not suffer boredom, stress or loss of concentration as human beings. They can perform the same operation with the same accuracy and speed.
A computer has four functions
- Accept data – input
- processes data – processing
- produces data – output
- stores results – storage
Input: input devices allow the computer to communicate with the user. All data is entered into the computer using an impute device like keyboard or mouse. These input devices accept data as originally planned.
Storage(memory): once data has been imputed to the computer using the keyboard or mouse it is sent to the main memory by the control unit(CU). Once the data is processed it is sent back today main memory which stores its temporarily before the next command is executed.
Processing: processing is the process of transforming data into information. It’s can’t involve grouping, sorting, grading and classifying. Processing is done by the central processing unit (CPU). The CPU which is the brain of the computer is made up of the arithmetic and logic unit (ALU), they control unit, main memory and register. They control units also send signal and commands to various parts of the computer system to prepare and accept data. The arithmetic and logic unit does all the arithmetic calculations and logic operations.
Output: The information (processed data) is sent to any secondary storage device such as hard disk, floppy disk, flash disk on the command of the control unit or sent to a printer or plotter for printing to get a hard copy. The action which takes place from the time that is imputed to the time the information is passed out is known as processing.
Parts of a computer: a computer is a system of many parts working together. The physical parts which you can see and touch are collectively called hardware. While software on the other hand refers to the instructions or programs that tell the hardware what to do. The main parts of a computer include the following
- System unit
- monitor
- keyboard
- printer
- speakers
- mouse
System unit: The system unit is the actual computer, everything else is called peripheral device. Your computer’s system unit probably has at least one floppy disk drive and one CD or DVD drive into which you can insert floppy disks and CDs. There’s another disk drive, called the hard disk inside the system unit. Everything that is currently in your computer is actually stored on that hard disk.
The system unit is the core of a computer system. Usually it is a rectangular box placed on or underneath your desk. Inside this box are many electronic components that process information. The most important of this component is the central processing unit (CPU), or microprocessor which acts as the brain of your computer. Another component is random access memory (RAM) Which temporarily stores information that the CPU uses while the computer is on. The information stored in RAM is erased when the computer is turned off. Almost every other part of your computer connects to the system unit using cables. The cables plug into specific ports (openings) typically on the back of the system unit. Hardware that is not part of the system unit is sometimes called a peripheral device. Some of the components of a system unit include motherboard, hard drive, floppy drive and CD drive, processors and RAM.
The floppy drive and CD drive are often referred to as removable drives, because you can’t remove whatever disk is currently in the drive and replace it with another. Your computers had discount store as much information as tens of thousands of floppy disks, So you don’t have to worry about running out of space on your hard disk anytime soon. As a rule you want to store everything you create or download on your hard disk. Use the floppy disks and CDs to send copies of files through the mail or to make backup copies of important items. The computer has one or more disk drives all devices that store information on a metal or plastic disk. The disk preserves the information even when your computer is turned off.