Optical Disk

• Optical Disk :-

                                        Laser is used to read and write data on Optical Disk. To save data on disk laser beam creates small holes on disk. Optical drive laser beam able to read the holes on disk. The presence of holes indicates 1 and absent indicates 0. 

Optical technology work fast then a magnetic method. 

• Types of Optical Disk :-

1). CD :-

                

                      A CD ROM an acronym of " Compact Disc Read Only Memory " is a pre-pressed  compact disc that contains data accessible to, but not writable.

 CD ROM are popularly  used to distribute computer software, including video games and multimedia applications, through any data can be stored (up to the capacity limit of a disk.


2). DVD :-

                 DVD ROM stands for " Digital Versatile Disc Read only Memory " and refers to a drive that can read dvd discs. The advent of DVD ROM drives has made it easier for computers users to access large amounts of data as well as providing a medium for watching videos. DVDs can hold many times of the storage of a CD.

 So, Computer applications that required four or five CDs should be consolidated into a single disc. Video and commercial movies could be played on the computer as well. 

Hard Disk

• Hard Disk :-

 

                             Hard disk drive is a type of magnetic disk. It consisit round plates called platter. Data store on platter A head fix on plates to read and write data. Platters usually constructed of aluminum or glass which cannot be bent like floppy disc hence termed as hard disk. A hard disk drive normally has one head per platter with all heads mounted on common rack. The had disk spins the disk as 3600, 5400, and upto 7200 or even more RPM (rotation per minute).  We save a lot of data on hard disk. Hard disk is used in computers to save the important data. 

• Basic Hard Drive Components:

• Disk Platters
• Read/Write head
• Spindle motor
• Head actuator mechanism
• Logic Board
• Cable and Connectors
• Configuration items

• Sector in Hard Disk :-

                          Sector is a section of a tracks which stores a predetermined number of Bytes

Floppy Drive

•  Floppy Disk :-

                    Floppy disk is a data storage medium that is composed of a disk of thin, flexible (''floppy'') magnetic storage medium sealed in a square or rectangular plastic carrier lined with fabric that removes dust particles. Floppy disks are  read and written by a floppy disk drive.

• In average floppy disk memory is '' 1.44 MB '' 

Magnetic Disk

Dear Member,

     This is our first post related to Storage Devices Session...

In this post we tell you about the knowledge of Magnetic Disk and its importance...

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• Magnetic Disk :-

               A memory device, such as floppy disk, or a removable cartridge, that is covered with a magnetic coating on which digital information is stored in the form of microscopically small, magnetic needles. The disk surface is divided into concentric tracks (circles within circles). The thinner the tracks, the more storage. The data bits are recorded as tiny magnetic spots on the tracks. 

The smaller the spot, the more bits per inch and greater the storage. Tracks are further divided into sectors, which hold a block of data that is read or written at one time; for example, READ SECTOR 782, WRITE SECTOR 5448.

 In order to update the disk, one or more sectors are read into the computer, changed and written back to disk. The operating system figures out how to fit data into these fixed spaces.

Storage Devices

Dear Members,

           ''Output Devices session is now completed on IT School''

So, now the Session of Storage Devices will be start soon. 

• Storage Devices :-

A storage device is s hardware capable of storing information. There are two storage devices used in computer a primary storage device such as computer RAM and a secondary storage device such as a computer hard disk drive.

 

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Printer

Dear Member,

        ''This is our last post related to Output Devices Session''

In this post we give you brief knowledge about Printer its types & its uses...

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• Printer :-

                              A device that prints text or illustrations on paper. A computer printer is a computer peripheral device that produces a hard copy (permanent human readable text or graphics, usually on paper) from data stored in a computer connected  to it. A printer is used to print anything that you want, like pictures or documents or data. Printers are awesome devices that plugin where there is a USB slot, from there you can click print and the document is sent to the port where your document is printed onto the piece of paper. You can print images, documents, cards etc.

• Types of Printer :-

1). Impact printers

2).Non impact printers 

• Impact Printers :-

Impact printer produces text and images when tiny wire pins on print head strike the ink ribbon is physically contacting the paper.

• Daisy Wheel Printer :-

                             A type of printer that produces letter quality type. A daisy wheel printer works on the same principle as a ball head typewriter. The daisy wheel is a disk made of plastic or metal on which characters stand out in relief along the outer edge. To print a character, the printer rotates the disk until the desired letter is facing the paper. Then a hammer strikers the disk, forcing the character to hit an ink ribbon, leaving an impression of the character on the paper. You can change the daisy wheel to print different fonts.

• Dot Matrix Printer :-

                             A type of printer that produces characters and illustrations by striking pins against an ink ribbon to print closely spaced sots in the appropriate shape. Dot matrix printers are relatively expensive and do not produce high quality output.

• Non impact Printers :-

Non impact printers are much quieter than impact printers as their printing heads do not strike the paper.

              Most non impact printers produce dot matrix patterns. Several different technologies have been used to provide a variety of printers.

        The main types of non impact printers are :-

• Thermal Printer
• Laser Printer
• Ink Jet Printer

1). Thermal Printers :-

                                  

                             A thermal printer uses heat to form an image onto a special kind of paper. This paper have a coating that changes to black color when exposed to heat over a period of time.

2). Laser Printers :-

                             A type of printer that utilizes a laser beam to produce a image on a drum. The light of the laser alters the electrical charge on the drum whenever it hits. The drum is then rolled through a reservoir of toner, which is picked up by the charged portion of the drum. Finally, the toner is transferred to the paper through a combination of heat and pressure. This is also the way copy machines work.

3). Ink Jet Printers :-

                                        Inkjet printers are the most common type o consumer printers. The inkjet technology works by spraying very fine drops of ink on a sheet of paper. These droplets are ''ionized'' which allows them to the directed by magnetic plates in the ink's path. As the paper is fed through the printer, the print head moves back and forth, spraying thousands of these small droplets on the page. 

Liquid Crystal Display (LCD)

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      In this lesson we will tell you about Liquid Crystal Display (LCD) also tell you how its work....

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• Liquid Crystal Display (LCD) :-

                          LCD is a short of Liquid Crystal Display, a type of display used in digital watches and many portable computers.

 

 LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric Current passed through the liquid causes the crystal to align so that light cannot pass through them.

                Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light.

Monitor

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      This is our first lesson related to Output Devices Session...

In this lesson we give you knowledge about the Monitor and its types.

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• Monitor :-

Monitor is an output device which used to display your data coming from the computer. It is just like a TV. The most important aspect of a monitor is its screen size. Like television, screen sizes are measured in diagonal inches, the distance from one corner to the opposite corner diagonally.

                             It can be any size like 14 inch 17 inch 21 inch etc. The resolution of a monitor indicates how densely packed the pixels are. In general, the more pixels (often expressed in dots per inch), the sharper the image. Most modern monitors can display 1024 by 768 pixels, the SVGA Standard. Some high end models can by 1200. With respect to color.

• Types of Monitor :-

There are many types of Monitor some are mentioned below :-

• Monochrome:-

Monochrome monitors actually display two colors, one for the background and one for the foreground. The colors can be black and white, green and black, or amber and black.

• Gray-scale :-

   A gray-scale monitor is a special type of monochrome monitor capable of displaying different shades of gray.

• Color Monitor :-

                        Color monitors can display anywhere from 16 to over 1 million different colors. Color monitors are sometimes called RGB monitors because they accept three seprate signals - -red, green, blue.

• CRT Monitors :-

                            

                                 Abbreviation of cathode ray tube, the technology used in most televisions and computer display screen. A CRT works by moving an electron beam back and forth across the back of the screen. Each time the beam makes a pass across the screen, it lights up phosphor dots on the inside of the glass tube, thereby illuminating the active portions of the screen. 

By drawing many such lines from top to the bottom of the screen, it creates an entire screen full of images.

Output Devices

Dear Members,

  Input Devices Lessons are completely shared on IT School...

Now the Session of Output Devices will be start soon. Here i want to tell you that we will discuss some important devices step by step in our upcoming lessons. So, Its easy for you to learn

So keep visiting IT School and learn free IT Education at no cost. If you like our blog don't forget to give a feedback.

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Touch pad

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           In this lesson you will learn about Touch Pad and its uses...

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• Touch Pad:-

                             A touch pad (or track pad) is a pointing device featuring a tactile sensor, a specialized surface that can translate the motion and position of a user’s figure to a relative position on screen. 

They are a common feature of laptop computers and also used as a substitute for a computer mouse where desk space is scare. Touch pad’s vary in size. 

Joystick

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        In this lesson we will give you knowledge about the Joystick and its uses....

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• Joystick:-

A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Joysticks are often used to control video games, and usually have one or more push buttons whose state can also be read by the computer. 

Joysticks are also used for controlling machines such as cranes, trucks, under water unmanned vehicles, wheelchairs, surveillance cameras.

Track Ball

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        In this lesson we will increase your knowledge about the track ball and its uses....

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• Track Ball:-

                     

                              Trackball is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of a ball about two axes- like an  upside down mouse with an exposed protruding ball.

 The user rolls the ball with the thumb, fingers or a palm of the hand to move a cursor.

Scanner

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        This lessons will increase your knowledge and you will know about the Scanner and its uses..

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• Scanner:-

                      

                    It’s a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop (or flatbed) scanner where the document is placed on a glass window for scanning hand held scanners,

 where the device is moved by hand, have evolved from text scanning “wands” to 3d scanners used for industrial design, reverse engineering, test and measurement, orthodontics, gaming and other applications.

Mouse

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       Today we are going to share with you new lesson......

In this lesson we will give you knowledge about Mouse and its types & uses.

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• Mouse:-

   A device that controls the movement of the cursor or pointer on the screen. A mouse is a small object you can roll along a hard, flat surface. Its name is derived from its shape, which looks a bit like a mouse, its connecting wire that one can imagine to be the mouse’s tail, and the pointer on the display screen moves in the same direction.

Mice contain at least one buttons as many as three, which have different functions depending on what program is running. Some newer mice also include a scroll wheel for scrolling through long documents.

·        Types of Mouse:-

Mechanical:-

                        Has a rubber or metal ball on its underside that can roll in all directions, Mechanical sensors within the mouse detect the direction the ball is rolling and move the screen pointer accordingly.

Opto Mechanical:-

                        These mouse same as a mechanical mouse, but uses optical sensors to detect motion of the ball.

Optical:-

                        Uses a laser to detect the mouse movement. You must move the mouse along a special mat with a grid so that the optical mechanism has a frame of references. Optical mice have no mechanical moving parts. The respond more quickly and precisely than mechanical mice, but they are also more expensive.

Keyboard

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            Today we are going to share with you first lesson related to Input devices. In this post we will give you knowledge about Keyboard and its uses...

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• Keyboard:-

 

1.      

 The set of typewriter like keys that enables you to enter data into a computer. Computer keyboards are similar to electric typewriter keyboards but contain additional keys. The keys on computer keyboards as follows:-

1.       Alphanumeric keys

2.     Modifiers keys

3.     Navigation and typing keys

                               The standard layout of letters, numbers and punctuation is known as a QWERTY keyboard because the first six keys on the top row of letters spell QWERTY. The QWERTY keyboard was designed in the 1800s for mechanical typewriters and was actually designed to slow typists down to avoid jamming the keys. Another keyboard design, which has letters positioned for speed typing, is the Dvorak keyboard.

• Alphanumeric Keys:-

Alphanumeric, numeric and punctuation keys are used in the same fashion as a typewriter keyboard to enter their respective symbol into a word processing program. The Space bar is a horizontal row is the lower most rows, which is significantly wider than other keys. Its main purpose to enter the space between words during typing. It is large enough so that a thumb from either hand can use it easily.

• Modifiers:-

Modifiers keys are special keys that modify the normal action of another key, when the two are pressed in combination.

For Example:-

<Alt> + <F4> in the Microsoft windows will close the program in an active window. The most widely-used modifiers keys include the Control key, Shift key and the Alt key.

• Navigation and Typing Modes:-

Navigation keys include a variety of keys which move the cursor to different positions on the screen. Arrow keys are programmed to move the cursor in a specified direction. ‘Page Up’ and ‘Page down’ keys, scroll the page up and down. The Home key is used to return the cursor to the beginning of the line where the cursor is located; The End key puts the cursor at the end of the line. The tab key advances the cursor to the next tab stop.