Introduction to Computers

S OFTWARE & H ARDWARE : Software – set of instructions that tells the computer what to do. It consists of the programs used to direct the operation of a computer. Hardware - The machines, wiring, and other physical components of a computer or other electronic system.

D ATA & I NFORMATION : Data – Facts and statistics collected together for reference or analysis. The quantities, characters, or symbols on which operations are performed by a computer, being stored and transmitted. Data is a valuable asset for an organization. Information - The manipulated and processed form of data is called information. It is more meaningful than data. It is used for making decisions.

D ATA P ROCESSING L IFE C YCLE :

I NPUT D EVICES : A device that can be used to insert data into a computer or other computational device.

T YPES OF M OUSE : Mechanical mouse Optical mouse

Wireless mouse Transmitter & receiver

T YPES OF K EYBOARDS : QWERTY keyboard Enhanced keyboard Wireless/ cordless keyboard

T YPES OF K EYBOARDS : Portable keyboard Ergonomic keyboard

O PTICAL SCANNER / S CANNER : Captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. A device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Typical scanners support resolutions of from 300 to 600 dpi. Professional scanner scans at 1200 dpi or higher. Optical Character Recognition software reads the document image and converts it into the text that can be edited in word processor.

T OUCH P AD / TRACKPAD : It is used to position or move the curser according to the finger movement on the touchpad. A touchpad is a pointing device featuring a tactile sensor, a specialized surface that can translate the motion and position of a user's fingers to a relative position on screen.

P OINTING STICK : A small rubberized device located in the center of a computer keyboard, which is moved with a finger tip to position a pointer.

P EN I NPUT : The mobile users usually input data and instructions using a device like a pen for writing or drawing on a flat surface Stylus: Stylus is a pointing and drawing device shaped like a pen, and used with a digitizing tablet or touch screen. The stylus point is made of a non scratching plastic to "write" on Personal Digital Assistants (PDAs) or any similar device Screen. The input is given with pressure instead of ink

P EN I NPUT : Digital pen: An input device which captures the handwriting or brush strokes of a user, converts handwritten analog information created using "pen and paper" into digital data, enabling the data to be utilized in various applications. For example, the writing data can be digitized and uploaded to a computer and displayed on its monitor. The data can then be interpreted by handwriting software (OCR) and used in different applications or just as graphics.

U SING PEN INPUT : The pen input is used with touch screens A graphic tablet can be attached with the computer if touch screen is not available. A graphics tablet (or digitizer, digitizing tablet, graphics pad, drawing tablet ) is a computer input device that enables a user to hand- draw images and graphics, similar to the way a person draws images with a pencil and paper. These tablets may also be used to capture data or handwritten signatures. It can also be used to trace an image from a piece of paper which is taped or otherwise secured to the surface. Capturing data in this way, either by tracing or entering the corners of linear poly-lines or shapes is called digitizing.

G AME PAD : A gamepad (also called joypad or control pad ), is a type of game controller held in two hands, where the digits (especially thumbs) are used to provide input. Gamepads generally feature a set of action buttons handled with the right thumb and a direction controller handled with the left

G AME W HEEL : Output device that uses a steering wheel and a separate set of foot pedals to imitate real world driving

A UDIO I NPUT D EVICES : Process of entering any sound into computer is called audio input Audio devices converts sound into a form that can be processed by a computer Sound card is required to enter high quality sound into PC Microphone: is an acoustic-to-electric converter or sensor that converts sound into an electrical signal. MIDI devices: are used to enter music and other sound effects from piano to computer

V OICE I NPUT : The process of entering data by speaking into microphone attached to computer Voice recognition/Speech recognition: Ability of a computer to distinguish spoken words Speaker dependent Software: Computer stores the voice patterns of words repeatedly spoken by user Speaker Independent Software: User doesn't train the computer. Software has built in set of word patterns

I MAGE CAPTURING DEVICES : Digital camera (or digicam ): takes video or still photographs, or both, digitally by recording images via an electronic image sensor doesn't require a roll of film Unwanted pictures can be erased preview your photos Quality of digital camera depends upon its resolution Resolution: Image Sharpness

MICR READER Magnetic Ink Character Recognition, or MICR, is a character recognition technology used primarily by the banking industry to facilitate the processing of cheques and makes up the routing number and account number at the bottom of a check. MICR (magnetic ink character recognition) is a technology used to verify the legitimacy or originality of paper documents, especially checks.

RFID READER : Radio-frequency identification ( RFID ) is a technology that uses radio waves to transfer data from an electronic tag, called RFID tag or label, attached to an object, through a reader for the purpose of identifying and tracking the object. The RFID tag includes a small RF transmitter and receiver.

M AGNETIC S TRIPE C ARD READER Magnetic stripe card/ swipe card /magstripe: is a type of card capable of storing data on a band of magnetic material on the card. It reads the magnetic stripe on the back of credit cards and bank cards. It is used to identify user, account no, card expiry, country, Card issuing company The magnetic stripe, sometimes, is read by physical contact and swiping past magnetic reading head.

B IOMETRIC INPUT DEVICES : Biometrics are automated methods of recognizing a person based on a physiological or behavioral characteristic. Among the features measured are; facial patterns, fingerprints, hand geometry, handwriting, iris, retinal, vein, DNA, and voice. Biometric device converts personal characteristic in digital code stored in computer.

B IOMETRIC INPUT DEVICES : Finger Print reader Facial recognition system Hand geometry system Voice verification system Signature verification system Iris recognition system Line of sight Systems

P ROCESSING D EVICE In terms of computing, computer processing devices are accountable for retrieving information as well as storing said information. The information on the computer is processed by CPU, or Central Processing Unit.

O UTPUT D EVICES : Peripheral equipment that converts a computer's output to a form that can be seen, heard.

T YPES OF O UTPUT : Text Graphics Audio Video Hard Copy / Soft copy

P RINTERS As peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Impact printers Daisy wheel 2. Dot matrix Non Impact printers Tonner based (Laser) 2. Liquid ink(Inkjet)

D OT M ATRIX PRINTERS Impact printers that use a matrix of small pins to create precise dots. Dot-matrix printers use a set of closely spaced pins and a ribbon to print letters or other characters on a page. Dot-matrix printers vary in terms of speed and the number of pins they have. They can run at a speed anywhere between 50 and 500 CPS (Characters Per Second).

D AISY WHEEL PRINTERS Daisy-wheel printers operate in much the same fashion as a typewriter. A hammer strikes a wheel with petals, the "daisy wheel", each petal containing a letter form at its tip. The letter form strikes a ribbon of ink, depositing the ink on the page and thus printing a character. By rotating the daisy wheel, different characters are selected for printing.

L INE P RINTERS / C HAIN PRINTERS Line printers, as the name implies, print an entire line of text at a time In chain printers, also known as train printers, the character set is arranged multiple times around a chain that travels horizontally past the print line. In either case, to print a line, precisely timed hammers strike against the back of the paper at the exact moment that the correct character to be printed is passing in front of the paper.

I NK - JET PRINTERS Ink-jets(bubble-jets) printers spray ionized tiny drops of ink onto a page to create an image. This is achieved by using magnetized plates which direct the ink's path onto the paper in the desired pattern. Ink-jet printers are capable of producing high quality print which almost matches the quality of a laser printer.

L ASER PRINTER : Laser printers operate by shining a laser beam to produce an image on a drum. The drum is then rolled through toner, and the electrically charged portions of the drum pick up ink. Finally, using a combination of heat and pressure, the ink on the drum is transferred onto the page. Color laser printers use the same toner-based printing process as black and white ( B/W) laser printers, except that they combine four different toner colors. Color laser printers can also be used as a regular black and white laser printer.

T HERMAL PRINTER That uses heat process to transfer colored dyes or inks to the paper Photo Printer: A photo printer is a color printer that can produce images that mimic the color range (gamut) and resolution of prints made from photographic film. Many can be used on a standalone basis without a computer, using memory card or USB connector. Portable Printer: Small light weight and battery powered printer. It uses ink jet, thermal, technology and connects to parallel or USB port Label / Postage Printer: Small printer that prints on adhesive type material that can be placed on different items like envelopes, packages, CDs, toys etc

P LOTTER A plotter is a vector graphics printing device which operates by moving a pen over the surface of paper large-scale printers that are very accurate at reproducing line drawings. They are commonly used for technical drawings such as engineering drawings or architectural blueprints

S YSTEM U NIT : The main body of a computer, consisting of a plastic /met al enclosure, the motherboard, and (typically) internal dis k drives, a power supply, cooling fans, and whatever circuit board is plugged into the mother board.

S YSTEM UNIT - ( OPEN ):

S TORAGE D EVICES : A hardware device, such as a hard disk or floppy disk, used to record and store data

C OMMUNICATION D EVICES : Communication devices are the machines that assist in transmission of data