Input Hardware

Hardware

The physical components that build the entire computer system is defined as hard ware. It includes input and output devices, CPU, and other electronic components like resistors, capacitors, integrated circuits (ICs) etc. The functions of hardware is to accept raw data as input, manipulate or process the data into valuable information, store the data and information for future use, and finally display the required information as output. But it is possible by using the software system. Basically there are three types of computer hardware. These are divided according to the working components of computer system. These are input hardware which are called input devices, processing hardware which are called processing components and out hardware which are output devices. Relationship between Hardware and software Software refers to the computer programs that are loaded into computer system and hardware refers to all the visible devices, which are assembled together to build a computer system. Hardware is physical part of computer and it is nothing unless it has software to control it. Software is a set of instruction that tells the hardware what to do and how to perform the requested actions.

Input hardware

Data , instructions and program that help to perform some processing on computer are called Input. Some devices that are used to accept such inputs to provide to the processing section are called input devices. Popular input devices are: keyboard, mouse scanner, digital camera etc.

Keyboard

Keyboard is a standard input device. It is a data entry platform of computer. The layout of keyboard is like traditional QWERTY typewriter, although some extra command and function keys are provided for internet, multimedia, operating system and software operation. Some types of standard keyboard: XT(Extended Technology): 83 keys AT( Advanced Technology): 101 keys Enhanced Technology: 103 keys In apple Macintosh, ADB (Apple Desktop Bus) keyboard is used. It is connected to Apple Desktop Bus.

Mouse

Mouse is a point and click input device with two or three buttons. The first mouse was built in 19968 by Douglas Engelbart at Stanford Research Institute. This mouse is bulky and made from wood piece with two gear wheels. The Douglas Englebart is known as inventor of Mouse. There are many technology applied in designing of mouse. The optical mouse is based on laser technologies. Scroll wheel mouse has facilities to scroll page upward and downward direction. Now a days we can get wireless mouse that works using electromagnetic wave like remote controller of TV system.

Scanner

Scanner is an input device which is used to enter pictures, graphs and other documents in computer and allow saving in different formats. It has main two components: Data capturing sub system: is used to illustrate image and convert into optical form. Image processing Subsystem: is used to convert optical image into digital. The resolution varies from 72 PPI (Pixel Per Inch) to 2400 PPI. Black and white color scanners are available in market in reasonable cost. Basically, we have four types of scanners i.e. flatbed scanner, sheet-fed scanner, hand held scanner and drum scanner.

Joystick

Joystick is also a pointing device which is mainly used for interaction with computer games. It consists of a lever, or stick, which is moved by the user and transmits these movements to the computer. It also normally has additional buttons or switches that are used in addition to the stick.

Joy pad

Joy pad is a device similar to joystick which is designed for gaming input. In many ways it is identical to joystick, with main difference being the use of multi-directional touch pad in the place of stick. It is most commonly used with games consoles, but also suitable for computers.

Touch screens

The touch screen is a modern and advance technology applied in wrist watch, camera, pager etc. it is a screen with touch sensitive points or program icons. When specific point or icon is touched by finger tips, related program or prompts are activated. There are three types of touch screen technology. These are capacitive screen, infrared screen and pressure screen. By touching and pressing on such screen user can give input to the system.

Light pen

Light pen is an input pointing device used to draw diagram on VDU (Visual Display Unit) directly. It is connected with VDU. The tip of pen contains light sensitive element, which are placed against the screen enabling to computer to identify the location of the pen on the screen. It is used in engineering drawing, architect design, circuit design and other several graphics and art works. It is also used as pointing device for menu displayed on VDU (Visual Display Unit) like a mouse.

Output Hardware

These are popular output devices. The result of processed data is called output. There are two types of output. Hard output which is the result printed on paper and soft output which is the result available as visual and audio form. There are different devices used to provide result to the user. These are called output devices. Popular output devices are printer, monitor, and plotter etc.

Monitor

Most popular and commonly used output device is monitor. It displays the character and graphic on screen. According to the technology used on the monitor, we have two types of monitor. CRT monitor: Common monitor that uses large vacuum tube called Cathode Ray Tube (CRT) and CRT monitor. It looks like a common TV screen. It is old type of monitor and big in size but cheaper in price.

LCD Monitor: A flat-panel monitor that uses special kind of liquid crystal to display the character and graphics are called Liquid Crystal Display (LCD) monitor. These are portable in size but expensive than CRT monitor. It consumes less power than CRT monitor.
CRT Monitor: Common monitor that uses large vacuum tube called Cathode Ray Tube. It looks like a common TV Screen. It is old type of monitor.

Printer

It is one of the most common hard output devices. It is used to print the result on the paper. Basically printers are divided into parts:

Impact printer: printer that prints the character like typewriters which characters are printed by physical striking over an inked ribbon. It is slow and poor quality printer. It is noisy printer but it is cheaper for operation.
Non-impact printer: Printer that prints the character using heat, light and ink spray technique. It is quite printer. It is faster than impact printer. Its quality is good but it is expensive than impact printer.

Inkjet Printers

Inkjet printers are non-impact printers which print text and images by spraying tiny droplets of liquid on the paper. They are the most popular printers for home use. Currently, most inkjet printers use either thermal inkjet. The inkjet head designs also divided into two main groups: fixed-head and disposable head.

Advantages of inkjet printers

Low cost.
High quality of output, capable of printing fine and smooth details.
Capable of printing in different color, good for printing pictures.
Easy to use.
Reasonably fast.
Quieter than dot matrix printer.

Disadvantages of inkjet printers

Print head is less durable.
Expensive replacement ink cartridges.
Not good for high volume printing.
Printing speed is not as fast as laser printers.

Laser printers

laser printers are non-impact printers which can print text and images in high speed and high quality resolution. Unlike inkjet printers, laser printer use toner (Black or color powder) instead of liquid inks. A laser printer consists of these major components: drum cartridge, rotating mirror, toner cartridge and roller.

Advantages of laser printers

High resolution
High print speed
Good for high volume printing

Disadvantages of laser printers

More expensive than inkjet printers
The cost of tone replacement and drum replacement is high
Warm up time needed to print

Dot-matrix printer

Dot-matrix printer is an impact printer that produces text and graphics when tiny wire pins on the print head strike the ink ribbon. The print head runs back and forth on the paper like a typewriter. When the ink ribbon presses on the paper, it creates dot that form text and images. Higher number of pins means that printer prints more dots per character, thus resulting in higher print quality. Dot-matrix printers were very popular and the most common type of printer for personal computer.

Advantages of dot matrix printer

Can print on carbon copies
Low printing cost per page
Can be used on continuous form paper
Reliable, durable

Disadvantages of dot matrix printer

Noisy
Limited print quality
Low printing speed
Limited colors printing

Plotter

A popular output device that prints engineering drawing charts and graphics are plotters. It prints high quality drawing and graphics.

There are two types of plotters.

Drum plotters
Flat bed plotters

MoDem

The full form of MoDem is Modulator Demodulator. It is an input as well as output device. It converts analog signals i.e. signals from wave and the cable to digital signal i.e. signal used by the computer to process data and vice-versa.

Processing Hardware

Basically processing hardware is the Central Processing Unit (CPU) of computer system. CPU is the central processing unit of the computer. It process data according to our instructions. Processing is a procedure that transforms raw data into meaningful information.

Memory unit

It is a part of CPU where all the given instructions, data and the results are stored during processing period. By using the unique address we can identify the locations of memory. There are different types of memory among them the popular are RAM (random Access Memory), ROM (Read Only Memory). Memory refers to the electronic holding place for instructions and data where the computers microprocessors can reach quickly. Computers need memory to store data and process them. We can represent the memory to store the data and process them. We can represent the memory using different units like 8 Bits = 1 byte (One Character) 1024 Byte= 1 Kilo Byte (KB) 1024 KB= 1 Mega Byte (MB) 1024 MB= 1 GB (Giga Byte) 1024 GB= 1 TB (Tera Byte)

Types of Memory

Basically we have two types of memory used on computer system. These are primary memory which is known as main memory or internal memory or simply memory and the secondary memory which is known as auxiliary memory or backup storage or external memory. Besides these two memories we have internal processor memories like cache memory, register, virtual memory etc.

Primary memory

The CPU contains the basic instructions needed to operate the computer, but it doesn't have the capability to store entire programs or data permanently. The CPU contains registers, but these are small areas that can hold only few bytes of data at a time. However, the CPU needs to have millions of bytes of space to hold programs and the data being manipulated.

Physically, memory consists of chips either on the motherboard or on a small circuit board attached to the motherboard. There are two types of memory:

Permanent/ Non-volatile Memory: Memory that store data permanently.Example: ROM
Temporary/Volatile Memory: Memory that will become empty after turned off the computer system.Example: RAM

RAM (Random Access Memory)

By memory, we generally mean RAM which is volatile in nature. It is a high speed memory that holds programs and data only when use. It requires constant supply of power. It is also called Read/Write Memory or volatile memory. The most important factor affecting the speed and power of a computer is the amount of RAM it has. The more RAM in a computer, the more it can do. The measuring unit of memory is byte, which is the amount of memory required to store a single character. RAM has the ability to access each byte of data directly, so it is named Random Access Memory. There are two types of RAM: SRAM (Static RAM) and DRAM (Dynamic RAM).

ROM (Read Only Memory)

These are non-volatile chips always holding the same data. Data in them can't be changed, that is, the contents in ROM cannot be written or erased by the user; these are 'hard-wired' or done only once by the manufacturer, hence they called Read Only Memory or sometime called permanent. Generally, ROM contains system programs for handling the operating system. There are different types of ROM: Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), and Electrically Erasable Programmable Read Only Memory (EEPROM).

Secondary Memory

These are used to store large volume of data permanently for the future use. These are non-volatile in nature. These are less expensive, so most computers have a large amount of secondary storage. However, they don't operate as fast as primary memory such as RAM. Secondary storage devices are often referred as back-up memory or external memory or additional memory. There are two types of secondary memory. They are:

Magnetic storage
Magnetic tape

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