Devices by chamudi semini (book recommendations .TXT) 📕

the input output and storage devices

 

 

 

Devises

 

 

Chapters

Input devises

Key board

Pointing devises

Mouse

Touch screens

Joystick

Light pen

Imaging and video input devices

Digital camera

Web cam

Scanners

Flatbed Scanner

Bar code Reader

Magnetic Ink Character Reader [MICR]

Optical Character Recognition [OCR]

Optical Mark Recognition [OMR]

Automated Teller Machine [ATM]

Microphone

 

Output devices

Soft copy

Monitor/Screen

Cathode Ray Tube [CRT] monitor

Liquid Crystal Display [LCD]

Light Emitting Diode [LED]

Multimedia projector

Hard copy

Printers

Impact Printers

Dot matrix printer

Line printer

Daisy wheel printer

Non-impact printers

Laser printer

Bubble printer/Ink jet printer

Thermal printer

Plotter

Sounds

Speaker

Storage devices

Magnetic Media Deices

Hard disk

Floppy disk

Magnetic tape

Optical Media Devices

CD

DVD

Blu-Ray

Solid State Devices

USB Flash drive

Memory card

 

 

 

 

 

 

 

 

 

 

 

 

Input devices

What is an input device?

The device that helps us to access or enter data is an input devise.

 

Name some input devices?

Keyboard

Pointing devices

Imaging and video input devices

Scanners

Microphones

 

 

 

Keyboard

Keyboard is the most common and very popular input device which helps in inputting data to the computer. The layout of the keyboard is like that of traditional typewriter, although there are some additional keys provided for performing additional functions.

Keyboards are of two sizes 84 keys or 101/102 keys, but now keyboards with 104 keys or 108 keys are also available for Windows and Internet.

There are few types of keys. They are as followings,

Typing keys

Numeric keypad

Function keys

Control keys

Spatial purpose keys

 

Pointing devices

Mouse

Mouse is most popular pointing device. It is a very famous cursor-control device having a small palm size box with a round ball at its base which senses the movement of mouse and sends corresponding signals to CPU when the mouse buttons are pressed.

 

Generally it has two buttons called left and right button and a wheel is present between the buttons. Mouse can be used to control the position of cursor on screen, but it cannot be used to enter text into the computer.

Advantages

Easy to use

Not very expensive

Moves the curser faster than the arrow keys of the keyboard

 

 

Touch screen

A touch screen is a device which is used to point things by touching the screen.

Advantages

Easy to point

Easy in using

Effective

 

Joy stick

Joystick is also a pointing device which is used to move cursor position on a monitor screen. It is a stick having a spherical ball at its both lower and upper ends. The lower spherical ball moves in a socket. The joystick can be moved in all four directions.

The function of joystick is similar to that of a mouse. It is mainly used in Computer Aided Designing (CAD) and playing computer games.

 

Light pen

 

Light pen is a pointing device which is similar to a pen. It is used to select a displayed menu item or draw pictures on the monitor screen. It consists of a photocell and an optical system placed in a small tube. When the tip of a light pen is moved over the monitor screen and pen button is pressed, its photocell sensing element detects the screen location and sends the corresponding signal to the CPU.

 

Imaging and video input devices

Digital camera

 

 

 

 

 

 

A digital camera is a camera that encodes digital images and videos digitally and stores them for later reproduction. Most use small removable cards to record the photos on.

Web cam

 

 

 

A webcam is a video camera that feeds or streams its image in real time to or through a computer to computer network. When "captured" by the computer, the video stream may be saved, viewed or sent on to other networks via systems such as the internet, and email as an attachment. When sent to a remote location, the video stream may be saved, viewed or on sent there. Unlike an IP camera (which connects using Ethernet or Wi-Fi), a webcam is generally connected by a USB cable, or similar cable, or built into computer hardware, such as laptops.

 

 

Scanners

Flatbed scanner

Flatbed scanner is an input device which works more like a photocopy machine. It is used when some information is available on a paper and it is to be transferred to the hard disc of the computer for further manipulation. Scanner captures images from the source which are then converted into the digital form that can be stored on the disc. These images can be edited before they are printed.

 

Bar code reader

Bar Code Reader is a device used for reading bar coded data (data in form of light and dark lines). Bar coded data is generally used in labelling goods, numbering the books etc. It may be a hand held scanner or may be embedded in a stationary scanner. Bar Code Reader scans a bar code image, converts it into an alphanumeric value which is then fed to the computer to which bar code reader is connected.

Magnetic Ink Character Reader [MICR]

MICR input device is generally used in banks because of a large number of cheques to be processed every day. The bank's code number and cheque number are printed on the cheques with a special type of ink that contains particles of magnetic material that are machine readable. This reading process is called Magnetic Ink Character Recognition (MICR). The main advantages of MICR is that it is fast and less error prone.

Optical Character Reader [OCR]

OCR is an input device used to read a printed text. OCR scans text optically character by character, converts them into a machine readable code and stores the text on the system memory.

 

Optical Mark Recognition [OMR]

OMR is a special type of optical scanner used to recognize the type of mark made by pen or pencil. It is used where one out of a few alternatives is to be selected and marked. It is specially used for checking the answer sheets of examinations having multiple choice questions.

 

Automated Teller Machine [ATM]

 

 

An ATM is a terminal specially designed for self-service banking.

A card reader: to capture the account information stored on the magnetic strips of the users' plastic cards.

A keypad: to allow the users to enter transaction information.

 

 

Microphones

 

Microphone is an input device to input sound that is then stored in digital form. The microphone is used for various applications like adding sound to a multimedia presentation or for mixing music.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Output devices

What is an output device?

An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system converts the electronically generated information into human-readable form.

Name some output devices?

Soft copy

Hard copy

Sounds

 

Soft copy

Monitor/Screen

Monitors, commonly called as Visual Display Unit (VDU), are the main output device of a computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form. The sharpness of the image depends upon the number of pixels.

Cathode Ray Tube [CRT]

The CRT display is made up of small picture elements called pixels. The smaller the pixels, the better the image clarity, or resolution. It takes more than one illuminated pixel to form whole character, such as the letter ‘e’ in the word help.

A finite number of characters can be displayed on a screen at once. The screen can be divided into a series of character boxes - fixed location on the screen where a standard character can be placed. Most screens are capable of displaying 80 characters of data horizontally and 25 lines vertically.

There are some disadvantages of CRT:

Large in Size

High power consumption

 

Liquid Crystal Display [LCD]

 

These use optical effects to convert sunlight or light from some other source into graphics patterns. Example is LCD (Liquid-Crystal Device)

 

Light Emitting Diode [LCD]

These devices convert electrical energy into light.

 

Multimedia projector

Multimedia Projector is a hardware device, with which an image, such as the computer screen, is projected onto a flat screen. Image data is sent to the video card, by computer, which is then translated into a video image and sent to the projector. A projector is often used in meetings or to make presentations, because they allow for a large image to be shown, with which the display is available for a large audience.

 

Hard copy

Printers

Printer is an output device, which is used to print information on paper.

Impact printers

The impact printers print the characters by striking them on the ribbon which is then pressed on the paper.

Characteristics of Impact Printers are the following:

Very low consumable costs

Very noisy

Useful for bulk printing due to low cost

There is physical contact with the paper to produce an image

Dot matrix printer

In the market one of the most popular printers is Dot Matrix Printer. These printers are popular because of their ease of printing and economical price. Each character printed is in form of pattern of dots and head consists of a Matrix of Pins of size which come out to form a character that is why it is called Dot Matrix Printer.

Advantages

Inexpensive

Widely Used

Other language characters can be printed

Disadvantages

Slow Speed

Poor Quality

 

Line printer

 

Line printers are the printers which print one line at a time.

 

Daisy wheel printer

Head is lying on a wheel and pins corresponding to characters are like petals of Daisy (flower name) that is why it is called Daisy Wheel Printer. These printers are generally used for word-processing in offices which require a few letters to be sent here and there with very nice quality.

Advantages

More reliable than DMP

Better quality

The fonts of character can be easily changed

Disadvantages

Slower than DMP

Noisy

More expensive than DMP

 

 

Non-impact printers

Non-impact printers print the characters without using ribbon. These printers print a complete page at a time so they are also called as Page Printers.

These printers are of two types

 

Laser printer

 

These are non-impact page printers. They use laser lights to produce the dots needed to form the characters to be printed on a page.

ADVANTAGES

Very high speed

Very high quality output

Give good graphics quality

Support many fonts and different character size

DISADVANTAGES

Expensive.

Cannot be used to produce multiple copies of a document in a single printing.

 

Bubble printer

Inkjet printers are non-impact character printers based on a relatively new technology. They print characters by spraying small drops of ink onto paper. Inkjet printers produce high quality output with presentable features.

They make less noise because no hammering is done and these have many styles of printing modes available. Colour printing is also possible. Some models of Inkjet printers can produce multiple copies of printing also.

ADVANTAGES

High quality printing

More reliable

DISADVANTAGES

Expensive as cost per page is high

Slow as compared to laser printer

 

Plotter

 

 

The plotter is a computer printer for printing vector graphics. In the past, plotters were used in applications such as computer-aided design, though they have generally been replaced with wide-format conventional printers. A plotter gives a hard copy of the output. It draws pictures on paper using a pen. Plotters are used to print designs of ships and machines, plans for buildings and so on.

 

Sound

Speaker

This is a output device which generates sound.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Storage devices

 

Magnetic media Disk

Hard discs

 

 

 

A hard disk drive (HDD) is a data storage device used for storing and retrieving digital information using rapidly rotating disks (platters) coated with magnetic material. An HDD retains its data even when powered off. Data is read in a random-access manner, meaning individual blocks of data can be stored or retrieved in any order rather than sequentially.

Floppy disk

 

 

 

 

A floppy disk, also called a diskette, is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles. Floppy disks are read and written by a floppy disk drive (FDD).

 

Magnetic tape

 

 

 

 

 

 

 

Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders. A device that stores computer data on magnetic tape is a tape drive

 

Optical media devices

CD

 

 

 

 

Compact disc (CD) is a digital optical disc data storage format. The format was originally developed to store and