Basics of Information Technology Part-2

The Shift key is pressed in common with other keys to produce upper case letters and the upper symbols shown on the keys The Control key is pressed in combination with other keys to initiate commands as specified by the software Ah The Alternate key is also used in combination with the keys to initiate commands Baclapar The Backspace is used to delete a character to the left of the cursor , moving the cursor hack one position . The cursor is the flushing indicator on the screen that shows where the nee character will be inserted The Enter key moves the cursor to the beginning of the med line . For instance it is used at the end of a paragraph Numeric keys : The numeric keys serve one of the two purposes , depending on the status of the Num Lock key . When the computer is in the Num Lock mode , these keys can be used to enter numeric data and mathematical symbols ( / for ” divided by ” for ” multiplied by ” , for subtraction and + fer ” addition ” ) . In the Num Lock mode , the status light under ” Num Lock ” key lights up When the computer is not in the Num Lock mode , the numeric keys can be used to move the cursor and perform other functions , as given below In some programs , the End key moves the cursor to the bottom PE right corner of the screen , End This key moves the cursor down one line . 3 Pen The Page Down key advances one full screen while the curse stays at the same place.

This key moves the cursor one character to the left This key moves the cursor one character to the right In some programs , the Home key moves the cursor to the top left corner of the screen Home This key moves the cursor one line up The Page Up key backs up to the previous screen while the cursor stays at the same place 9 PgUp 0 Ins The Insert key , when toggled off . causes keyed characters to override / affix with the existing characters . The Delete key deletes a character , space , or selected text . Del Extended keyboards include additional keys that duplicate the cursor movement functions of the numeric keys . Users who enter a lot of numeric data can leave their computers in the Num Lock mode and use these additional keys to control the cursor The Arrow keys , to the left of the numeric keys , move the cursor position , just as the numeric keys 2,4.6 . and 8 do when they are not in the Num Lock mode . Just above the Arrow keys are six keys — Insert , Delete , Home , End , Page Up , and Page Down — which duplicate functions of the numeric keys 0. decimal point ( Del ) , 7.1.9 , and 3 At the top of the keyboard , to the right of the function keys , are keys that perform additional tasks , as mentioned below : The Print Screen key causes the current screen display to be taken a copy of information or image on the screen Print Screen.

The Scroll Lock key causes lines of exigen cursor – to move . When the computer is in the Sello mode , the status light under Scroll Lock op The Pause key cause the screen to pause when informam appearing on the screen too ft to read Function Keyne These keys are at the top of a computer keyboard labeled F2 , F3 , F4 , F5 , 76 , F7 , F8 , P9 , FIO , F11 and Piz . The functionary easy way to give certain commands to the computer , which are wally operated by keyboard commands . They have different functions in differta program . These functions are particularly important in an application program Pointing devices : Pointing devices control the position of the curse pointer on the screen . They include the following : Mouse • Trackball Pointing Stick • Touch pad Touch Screen • Light pen • Digitizing / Graphic tablet • Pen – based system A brief description is given as under Mouse : A mouse is an input device that looks a little bit like a a ball on its underside that is rolled on a flat surface or mouse – pad . The role movement causes a corresponding cursor movement on the screen . It enal us to reposition the curser for pointer ) on the screen where ever we want also has buttons on its top which communicate certain commands to computer while pressed . In particular , button is often used to click on an in icon represents a computer activity or command ) to invoke the command Trackball : The trackball is a movable ball , on top of a stationary deved that is rotated with fingers or palm of the hand . Its popularity surged with advent of laptop computers where traveling users found themselves with a flat surface to roll the traditional mouse . It looks like the mouse turned up down and likewise , has additional buttons whose functions vary depending the software , Pointing Stick : A pointing stick is a pointing device that looks like a per eraser protruding from the keyboard between the G , H , and B keys . We me the pointing stick with our forefinger while using the thumb to press but located in front of the space bar . Another device like a Pointing stick is Joystick , It is a pointing device that consists of a vertical handle like.

gearshif lever mounted on a base with one of a buttons is basically used to video games and in some computer – aided desses Touch pad : The touch pad is a small flat surface which weder finger , asing the same movements as we would with me . As we move the finger , the cursor follows the movement . We click by tapping the fingsson the pad’s surface or by pressmg bution positioned close by the pad Touch pads are now common on the portabile computers apps ) . Touch Screen : A touch screen is a video display screen that is somstime to rocerve input from simply touching our fingers onto it is covered a plastic layer , behind which are invisible beams of frared Lught . Wely touch the provided buttons or menus and get the information on the display screen accordingly Light Pen : The light pen is a light sensitive stylus or police device connected by a wire to the computer terminal . The user brings the pes to a desired point on the display screen and presses the pen bon which identifies that screen location to the computer Engineers , graphic designers and illustrators use light peas Digitizing Graphic Tablet : A digitizing tablet consists of a tablet connected by a wire to a stylus or pack . A styles is a pes – like device with which the user sketches ” an image . A puck is a copying device with which the user copies an image , such as an architectural drawing or a civil engineering map Apack looks a bit like a mouse but has different types of buttons and a clea plastic section extending from one end with crosshairs printed on it . The ntersection of the crosshairs points to a location on the graphics tables which in turns mapped to a specific location on the screen Digitizing tablets are used primarily in design and engineering When used with drawing and painting software , a digitizing tables and stylus allow us to do shading and many other effects similar to those artists achieve with pencil pen , or charcoal . Alternatively , when we use a pack , we can trace a draw land on the tablet , and a digitized copy is stored in the computer Pen – Based Systems : In the next few years , students may be able to take notes in class without ink and paper , if pen – based computer systems are introduced . These computers use a pen – like styles to allow people to ente handwriting and marks onto a computer screen rather than typing on a keyboard . This system connects an instructor’s electronic whiteboard on the classroom wall with student’s pen computers , so that the students could receive notes directly , without having to copy information word for word ” The idea is that the students should concentrate on the lecture listening only Source Data – Entry Devices : These devices are used for direct data entry the computer systems . Few of them are as under.

Computer Science


Softcopy refer to data that is shown on a play screen or is in audio arvok form . This kind of cusput is not to be cannot be touched . Virtual reality and robot mught also beendered softcopy device Hardcopy refer to printed output . The principal examples are printouts , whether text or praphies from printers , plotes Display Screens ! Also known as CRT Monitor or simply screen , dille in size , color , resolution , and video display adapter card There are for inputting the data or displaying the information after pencensing Size : Monitor come in different sizes from small screen built into palmtop and laptop to extra largo monitors used for special purposes . Color : Many monitor display color Those RGB displays can create 256 colors and several thousand variations on them by blending shades of Res . Green , and Blue ( RGB ) . Monochrome displays show information using single foreground color on a contrasting background color Resolution : All the characters and images on a monitor are made up of da palters : the number of dot or pixels , per inch determines resolution , or the sharpness of the image . A higher number of pixels means a shaper image , Video Display Adapters : To display graphies , a display screen must have video display adapter attached with the computer . It is known as a video graphics card , and is a circuit board that determines the resolution number colors and speed with which images appear on the display screen . So fu there are three types of graphics cards introduced in the market . VGA : Video Graphics Array , support 16-256 colors , depending on screen resolution . Al 320 x 200 pixels , it will support 16 colors and at 640 x 480 pixels , 256 colors . It is called 4 – bit color Normal Sare Flat Serum DS SVGA : Super Video Graphics Array , support 256 colors at highet resolution than VGA has two graphics modes : 800 x 600 pixels ami 1024 x 768 pixels . It is called 8 – bit color , XGA : Extended Graphics Array , supports up to 16.7 million colors i resolution of 1024 x 768 pixels . Depending on the video display adapter memory chip , XGA will suppon 256 , 65536 , or 16.777.216 colors , called 24 – bit color or True color.

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