What is Computer ? Input and Output Devices of Computer

What is Computer ?

Computer is an electronic data processing device that is designed to work with information. The term Computer is derived from the latin term "computare", this means to calculate or programmable machine. Charles Babbage, an English mechanical engineer and polymath, originated the concept of a programmable computer. Charles Babbage is called the "Grand Father" of the computer.  Modern computers have the ability to follow generalized sets of operations, called programs. Computer is increasingly becoming compulsory in nearly all fields of studies, not because of anything but its accuracy and versatility in processing data. The computer is now a very vital tool for efficiency improvement and precision of job or task execution.

A computer is an electronic device, operating under the control of instructions stored in its own memory. These instructions tell the machine what to do. The computer is capable of accepting data (input), processing data arithmetically and logically, producing output from the processing, and storing the results for the future use. Computer components are divided into two major categories namely 'hardware' and 'software'. Hardware is the machine itself and its connected devices such as monitor, keyboard, mouse etc. Software are the set of programs that make use of hardware for performing various functions. Most people see their computers as tools that help them do jobs, rather than complex electronic machines they have to pre-program. Today, most computer users rely on prewritten programs like Microsoft Word, Excel, Power Point, or download apps for their tablets and smartphones without caring much how they got there. 

Uses of Computers :

Computers are used extensively in scientific research to solve mathematical problems, investigate complicated data, or model systems. Computers are used to track inventories with bar codes and scanners, check the credit status of customers, and transfer funds electronically. People use computers in many ways that are business, automobiles, homes, education and entertain.
● Computer - “Commonly Operated Machine Particularly Used in Technical and Educational Research”

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Functional Units of Computer :

● Input Unit - This unit is used for entering data and programs into the computer system by the user for processing.
● Storage Unit - The storage unit is used for storing data & instructions before and after processing.
● Output Unit - The output unit is used for storing the result as output produced by the computer after processing.
● Processing - The task of performing operations like arithmetic and logical operations is called processing.CPU includes Arithmetic logic unit (ALU) and control unit (CU).

Computer’s Memory :

Computer’s memory can be classified into 2 types; primary memory & secondary memory.

1. Primary Memory :

Primary Memory can be classified as RAM & ROM.
■ RAM -
It is the place in a computer where
the operating system, application programs & the data in current use are kept temporarily so that they can be accessed by the computer’s processor.
RAM - Random Access Memory
■ ROM -
ROM also stores an initial program called the
"bootstrap loader" whose function is to start the operation of computer system once the power is turned on. ROM is a special type of memory which can only be read & contents of which are not lost even when the computer is switched off.
ROM - Read Only Memory

2. Secondary Memory :

RAM is volatile memory having a limited storage capacity. Auxiliary/secondary memory is storage other than the RAM.Secondary storage devices are 2 types, magnetic and optical.
Magnetic devices include hard disks.
Optical storage devices are CDs, Pen drive, DVDs, Zip drive etc.
■ Hard Disk -
The hard disk and the hard disk drive exist together as a unit and is a permanent part of the computer where data and programs are saved. These disks have storage capacities ranging from 1GB to 80 GB and more.

■ CD (Compact Disk) -
Compact Disk is portable disk having data storage capacity between "650-700 MB". It can hold large amount of information such as full-motion videos, music, & text etc
■ DVD (Digital Video Disk) -
Digital Video Disk is similar to a CD but has larger storage capacity & enormous clarity. It can store several Gigabytes of data. DVDs are primarily used to store movies, music, & can be played back on your television.

3. Cache Memory :

Cache memory, also called CPU cache is a high-speed storage mechanism that is a reserved section of main memory or an independent high-speed storage device. There are 2 types of caching commonly used in computer systems, there are
a. Memory caching
b. Disk caching

4. How Computer Memory Is Measured :

   ● Bit - All computers work on a binary numbering system, i.e. they process data in one's or zero's. This 1 or 0 level of storage is
called a bit.
  ● Byte - A byte consists of eight bits.
  ● Kilobyte - A kilobyte (KB) consists of 1024 bytes.
  ● Megabyte -A megabyte (MB) consists of 1024 kilobytes.
  ● Gigabyte - A gigabyte (GB) consists of 1024 megabytes.

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Input & Output Devices :

● Input Devices -

When unprocessed data is sent to the computer with the help of input devices, the data is processed and sent to output devices. The act of processing is mainly regulated by the CPU.
Some examples of input devices are -
  1. Digital camera
  2. Keyboard
  3. Joystick
  4. Real-time clock
  5. Touchscreen
  6. Trackball
  7. Microphone
  8. Digital video
  9. Mouse
10. Image scanner
11. Overlay keyboard
12. Graphics tablet
13. Light pen
14. Optical Character Reader (OCR)
15. Magnetic Ink Character Reader Recognition (MICR)
16. Bar code reader
17. Badge reader
18. Digitizer
19. Optical mark reader (OMR)
20. Modem

● Output Devices -

Output devices consists of hardware that transfer information from the computer CPU to the computer user.
Some examples of output devices are -
  1. Video card
  2. Projector
  3. Computer monitor
  5. Sound card
  6. Printer
  7. speaker
  8. Plotters
  9. Video Graphic Adapter
10. Laser printers