WHAT IS A COMPUTER
Computer is an electronic device that executes the instructions given in a program and controls the operations that are expressible in numerical or logical terms.
Basically, a computer has four functions to perform
- Accepts data input
- Process data processing
- Produces Outputs
- Stores the output for further use
- The word computer has been derived from the Latin word computerae meaning 'to compute'.
- Charles Babbage is known as the father of computer.
WHAT MAKES A COMPUTER POWERFUL
The power computer can be judged in the following parameters
Speed : A computer can do billions of actions per second.
Reliability : A computer can be considered as highly reliable as failures are usually due to human error, one way or another.
Storage : A computer can store ample (More Than Enough) amount of data.
TYPES OF COMPUTER
There are different types of computer for different purposes. The types of computers are generally based on general performance levels.
Personal Computer or Micro Computer : Designed for personal use only. This type of computers can easily be moved from one place to the other. They have a personal storage area, input & output unit and a Central Processing Unit. Examples for microcomputer are desktop, laptop, mobile phone, tables, etc.
Mini Computer : A minicomputer is a type of computer that possesses most of the features and capabilities of a large computer but is smaller in physical size. A minicomputer fills the space between the mainframe and microcomputer, and is smaller than the former but larger than the latter.
Mainframe : Computers designed to be used in large firms and organisations where a lot of people have to work on the same database are called mainframe computers. They are almost equally as expensive as Supercomputers and are the fastest working computers at present. They are mostly used in Banks.
Super Computer : The computers which are used to process a huge amount of data at once are called Supercomputers. They are mostly used in scientific and engineering operations where the processing is complex. They are expensive and complicated to work. For example – The computers used by NASA to launch space shuttles.
COMPONENTS OF COMPUTER
Computers are made from various components that perform specific functions. Primarily, a computer system has the following components:-
(a) Inputs unit. An input is everything that we tell the computer. The input may be of various forms
Data. It is the raw facts given to the computer.
Programs. These are the sets of the instructions that direct the computer.
Commands. These are the special codes or keywords that the user inputs to perform a specific task. They may be selected by clicking on a command button.
Users Response. They are the users answer to the computer's question such as choosing OK, Yes or No or by typing in text.
The input is provided to the computer through various input devices such as keyboards, mouse, light pen, joy stick, magnetic ball, optical character leader (OCR), floppy disk drive, magnetic disc drive, Bar code reader, smart card reader, biometric sensors, touch screen, punched card reader, stylus and tablets, puck or microphone, digital camera, scanner, etc.
(b) Central Processing Unit (CPU) This unit processes the input whatever entered into the computer through the input devices. Processing is the manipulation of information inside the computer in a area called CPU. The CPU performs all the processing works of computer and controls all its parts and therefore also termed as the 'Brain of computer'. CPU is further classified into three components:-
Arithmetic Logic Unit (ALU)
- It is a part of the execution unit.
- It is a core component of all CPUs.
- It performs all arithmetic and logic operations.
- It consists of a number of small locations, termed as registers.
Control Unit (CU)
- It is the part of a CPU that directs its operation.
- It gives command to transfer data from input devices to memory and from memory to arithmetic logic unit.
- It transfers the results from memory to output unit.
(c) Memory Unit. It is also one of the most important parts of the computers. It stores data calculations and results into it and in case of needs, it sends the data in the form of output. The capacity of memory is measured in terms of byte, Kilobytes, megabytes and Gigabytes. There are two types of computer memory:-
Primary Memory. It holds the data received from input device. It holds the data being processed and intermediate results being generated. RAM is an example of computer's primary memory.
- RAM stands for Random Access Memory.
- All active programs and data are stored in RAM so that they are readily available and easily accessed by the CPU.
- It is also a volatile memory as the data stored in it get vanished by turning off the computer.
- It is also known as Temporary Memory.
- It is also called as Read and Write Memory.
Secondary Memory. Secondary Memory is known as permanent memory of the computer as the data stored in it remains forever.
ROM is an example of secondary Memory.
-ROM stands for Read only Memory.
- It is a non-volatile memory as it can keep its contents even without a power source.
- The data stored on ROM cannot be changed.
(d) Output Unit. An output is data that has been processed into useful forms, now called information.
Types of Output The output produced by a computer may be of two types
Hard copy. This output is printed on paper or other permanent media.
Soft Copy. This output is displayed on screen or by other non-permanent means.
Categories of output The output furnished by a computer may be categorized as follows:
Text Document. It includes reports, letters, etc.
Graphics. It includes charts, pictures, graphs, etc.
Multimedia. It includes a combination of texts, graphics, video, audio, etc.
The widely used means of output are printer and the computer screen.
-The output unit accepts the processed data (results) from CPU.
- It converts results from machine language into some simple language.
- It displays results to user.
- Virtual display unit (VDU), printer, plotter, floppy disc drive, magnetic disc drive, speaker, pen-drive are examples of output unit.
SOFTWARE
- It is a set of instructions that directs the computer to process information.
- Computer software can have various functions such as controlling hardware, performing, computations, communications with other software, human interaction, etc.
- Computer software cannot be touched or seen.
- It can be classified into three types
(i) System Software : It coordinates the operation of various hardware components of the computer eg. DOS, Windows 95, 98, ME, 2000, Unix, etc.
(ii) Application Software : It is a set of programs designed for specific uses or application eg.-MS Word, MS Excel, etc.
(iii) Utilities Software : Utility software are those that are very often requested by many application programs. it is used to debug the software errors, correct the data through the editor, sort data, etc. eg.-PKzip, Anti-Virus software, etc.
HARDWARE
- Hardware is any part of computer that can be seen by the eyes and felt by touching.
- The other external computer equipments are called peripherals.
- Printers, Modems, Scanners, etc, are the examples of hardware and software.
FIRMWARE
- Firmware is the technology which has the combination of both hardware and software.
- BIOS chip inside a computer is a typical example of firmware.
- This chip (hardware) is located on the motherboard and has the BIOS set up (software) stored in it.
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