COMPUTERS

A computer is a machine that manipulates data according to a list of instructions.

The first devices that resemble modern computers date to the mid-20th century (around 1940 - 1945), although the computer concept and various machines similar to computers existed earlier. Modern computers are based on tiny integrated circuits and are millions to billions of times more capable while occupying a fraction of the space. Today, simple computers may be made small enough to fit into a wristwatch and be powered from a watch battery. Personal computers, in various forms, are icons of the Information Age and are what most people think of as "a computer"; however, the most common form of computer in use today is the embedded computer. A computer can also be defined as a set of input devices, output devices and processing units. Input and output devices are integral parts of the computer system which enables the user to interact directly with the computer. Some of the input devices are Keyboard, Mouse, Barcode reader, Scanner, Webcam, Digital pen, Finger print scanner, Touch screen, Gaming devices, Microphones, etc..

INPUT DEVICEInput devices are the devices we use to put information INTO a computer.An Input device is any piece of computer hardware equipment used to provide data and control signals to a computing system. Input and output devices make up the hardware interface between a computer and the user or external world.Typical examples of input devices include keyboards and mouse. However, there are others which provide many more degrees of freedom. In general, any sensor which monitors, scans for and accepts information from the external world can be considered an input device, whether or not the information is under the direct control of a user.Any machine that feeds data into a computer. For example, a keyboard is an input device, whereas a display monitor is an output device. Input devices other than the keyboard are sometimes called alternate input devices. Mice, trackballs, and light pens are all alternate input device.Input devices can be classified according to :

The modality of input (e.g. mechanical motion, audio, visual, etc.)

whether the input is discrete (e.g. key presses) or continuous (e.g. a mouse's position, though digitized into a discrete quantity, is high-resolution enough to be thought of as continuous)

the number of degrees of freedom involved (e.g. many mice allow 2D positional input, but some devices allow 3D input, such as the Logitech Magellan Space Mouse)

Whether the input is direct or indirect. With direct input, the input space coincides with the display space, i.e. pointing is done in the space where visual feedback or the cursor appears. Touch screens and light pens involve direct input.

Examples involving indirect input include the mouse and trackball.

Whether the positional information is absolute (e.g. on a touch screen) or relative (e.g. with a mouse that can be lifted and repositioned)

1. KEYBOARD: As the name implies, a keyboard is basically a board of keys. Along with the mouse, the keyboard is one of the primary input devices used with a computer. The keyboard's design comes from the original typewriter keyboards, which arranged letters and numbers in a way that prevented the type-bars from getting jammed when typing quickly. This keyboard layout is known as the QWERTY design, which gets its name from the first six letters across in the upper-left-hand corner of the keyboard.Keyboard is a peripheral partially modelled after the typewriter keyboard.A keyboard typically has characters engraved or printed on the keys; in most cases, each press of a key corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence; other keys do not produce any symbol, but instead affect the operation of the computer or the keyboard itself. A majority of all keyboard keys produce letters, numbers or signs (characters) that are appropriate for the operator's language. Other keys can produce actions when pressed, and other actions are available by the simultaneous pressing of more than one action key.

TYPES OF Keyboard

1. Multimedia keyboards:

Multimedia keyboards offer special keys for accessing music, web, and other often-used programs. They also usually have other convenient controls, such as a mute button, volume buttons or knob, and standby (sleep) button. Multimedia keyboard has a standard keyboard layout with an easy one-touch media control to play CD, DVD and MP3 media files. It integrates the web, e-mail, search and other favourite applications with a one-touch Internet access key.

2. Gaming keyboards:

Some gaming keyboards offer extra function keys which can be programmed with keystroke macros. For example, ctrl+shift+y could be a keystroke that is frequently used in a certain computer game. But it is a physically awkward (or, at least, annoying) combination for the hands to reach for repeatedly. It may be very useful to assign that keystroke combination to one function key. Some keyboards (Such as the Logitech G11 or G15) have a keypad full of "G keys" to the left of the QWERTY keyboard for this purpose.

The development of these keyboards was spurred by gaming, but the concept can also be very convenient in non-gaming applications, such as office work. Any keystroke combination that is awkward or annoying but frequently needed can be replaced with a "G key". The meaning of the "G key" press can automatically change depending on which application has focus, thus extending the number of macros available given a certain limited number of G keys.

3. Flexible Foldable Mini Keyboard

This revolutionary keyboard is water – resistant, flexible dust and contaminant proof. The keyboard can be used in industrial environments, hospitals, libraries, marine and boating applications… infact anywhere where dust and liquids are present. The silicon-based material is impervious to almost anything! This washable, roll-able, foldable keyboard has been called “the best thing to happen to typing since the backspace key.”Ideal for travel, school or industrial applications, it fits in your briefcase, backpack or note book carrying case and you don’t have to worry about any sharp edges! The soft material allows a quick, reflexive typing action that is silent and more comfortable than hard plastic surfaces.

4. Wireless Keyboard

Sometimes sitting close to your computer monitor at a desk can be uncomfortable. Other times, there may be so many tangled wires behind your computer that you are unable to organize them. Regardless of which scenario you find yourself in more often, a wireless keyboard can help. A wireless keyboard is exactly the same as a normal computer keyboard except for one major difference: Wireless keyboards transfer typing data to the computer via infrared beams. A beam of information is sent from the keyboard, as you type, to a

receiver, which is plugged into the computer. This allows for a cordless experience, which eliminates the potential for another tangled cord behind your computer. It is also common for many consumers to purchase a wireless mouse to compliment a wireless keyboard. Wireless technology also allows you to place your wireless keyboard or mouse in a position that the corded-version may not reach. However, the infrared keyboard receiver must be placed in a location that is easily reachable by the infrared beam. This distance may vary from model to model, so check specifications before purchasing a wireless keyboard. If the keyboard is not pointed in the general direction of the receiver, or if the line-of-sight between the wireless keyboard and receiver is blocked, then the signal will not be transmitted to the computer. This can create a problem for the user if someone is walking between the keyboard and receiver or if the keyboard is not angled correctly.If you are sure that the space between your wireless keyboard and receiver will be relatively clutter free, a wireless keyboard can make a great addition to your home computer, freeing you up by providing more flexibility in the way you operate your computer system.

5.Smaller keyboards

A standard keyboard is physically quite large, as each key must remain large enough to be easily pressed by fingers. Other types of keyboards have been proposed for small portable equipment where a standard keyboard is too large. One way to reduce the size of the keyboard is to reduce the number of keys and use chording keyer, i.e. pressing several keys simultaneously. For example, the GKOS keyboard has been designed for small wireless devices. Other two-handed alternatives more akin to a game controller, such as the AlphaGrip, are also used as a way to input data and text.

Another way to reduce the size of a keyboard is to use smaller buttons and pack them closer together. Such keyboards, often called a "thumbboard" (thumbing) are used in some personal

digital assistants such as the Treo and BlackBerry and some Ultra-Mobile PCs such as the OQO.

2. MOUSE:The name mouse originated at the Stanford Research Institute, derives from the resemblance of early models (which had a cord attached to the rear part of the device, In computing, a mouse (plural mouse devices or mouses) is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of a small case, held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features can add more control or dimensional input. The mouse's motion typically translates into the motion of a pointer on a display, which allows for fine control of a Graphical User Interface.The mouse first became a widely-used computer tool when Apple Computer made it a standard part of the Apple Macintosh. Today, the mouse is an integral part of the graphical user interface (GUI) of any personal computer. The mouse apparently got its name by being about the same size and color as a toy mouse. A mouse consists of a metal or plastic housing or casing, a ball that sticks out of the bottom of the casing and is rolled on a flat surface, one or more buttons on the top of the casing, and a cable that connects the mouse to the computer. As the ball is moved over the surface in any direction, a sensor sends impulses to the computer that causes a mouse-responsive program to reposition a visible indicator (called a cursor) on the display screen. The positioning is relative to some variable starting place.

Laser mouse VS: Optical mouse

The difference between a regular optical mouse and a laser mouse is the light used to track movement. optical mouse uses an LED light in the optical engine, while a laser mouse uses a

laser to track movement. The more dots per inch (dpi) a mouse can track the more sensitive and accurate it is. A typical optical mouse tracks between 400dpi and 800dpi, while laser mouse track more than 2,000dpi.

Neither is really better; it all depends on your needs and preferences. Unless you're a gamer or a graphic artist with a need for precise movement, you'll probably find a 2,000dpi laser mouse too sensitive. Many gaming mouse, however, allow you to switch sensitivity levels so that you have precision when you need it but can revert to 400dpi or 800dpi for regular mousing.

Besides their tracking speeds, laser mouse work on nearly every surface, whereas optical mouse may experience trouble tracking on black or shiny surfaces.

Optical MouseAn optical mouse uses camera technology and digital processing to compare and track the position of the mouse, rather than a ball and rollers used on older mouse. This technology, first introduced by Agilent technologies in 1999, helps give users more precise performance without the maintenance and cleaning needed on older mouse.Inside each optical mouse is a small camera that takes more than a thousand snapshot pictures every second. A small LED (light-emitting diode) provides light underneath the mouse, helping to highlight slight differences in the surface underneath the mouse. Those differences are reflected back into the camera, where digital processing is used to compare the pictures and determine the speed and direction of movement. This differs from older-technology mouse, in which a round ball rolled against a mouse pad to indicate movement.Optical mouse have a number of benefits over older technologies. One of the biggest benefits is that the elimination of the mouse ball, which frequently required cleaning to scrape accumulated grime of the ball or the rollers inside. As there are no moving parts in optical mouse, almost no maintenance or regular cleaning is required. Another benefit is that digital processing often results

in smoother, more accurate performance than prior technologies. Optical mouse typically don't require a mouse pad and can be used on many surfaces, including those that are not entirely flat.

Laser MouseA laser mouse is a type of computer mousing device that uses a laser beam rather than a ball to track the movement of the user's hand. Laser mouse are common because they are perceived to have better tracking ability. In addition, they are not as subject to gumming up and subsequent distortion of the signal as conventional ball mouse. The lack of moving parts also makes them far less subject to damage. The optical mouse is also available in a wireless format, making it an extremely versatile and flexible tool for users who like to have free range of their cordless desks. With the introduction of a graphical user interface in the late 1980s, computer companies saw the need for some sort of device that could be used to interact with the computer, which had transcended the boundaries of the traditional text-based user interface. The mouse was introduced and became a quick success — very few computer users work without mouse now, although it is technically possible to utilize keyboard shortcuts to bypass the mouse. Optical and laser mouse were an excellent introduction to the computing world, because it is not as subject to interference. In general, the laser mouse moves very smoothly and accurately, although if the system memory is bogged down, it will cause the cursor to lag, along with everything else. In addition, the laser mouse can reflect from almost any surface, meaning that a mouse pad is not necessary.

Wireless MouseThe mouse is an extremely popular technology to interact with your computer. While the majority of mouse are connected directly to the computers peripheral input via a cord and are powered by the computers main power, wireless mouse are

becoming extremely popular to give computer user’s cordless accessibility to their mouse and to interact with their computer.

Wireless Mouse Technology

Wireless mouse usually work via radio frequencies commonly referred to as RF. RF wireless mouse require two components to work properly as a radio transmitter.

Three Types Mice of Wireless

Today, there are three different mouse technologies, MECHANICAL, OPTICAL and LASER.

MECHANICAL MOUSE uses a small rubber ball to calculate distance and position. However these mouse are very rarely manufactured anymore due to the fact that they get dirty easily and are slow to process information.

OPTICAL MOUSE is the de facto standard for mouse today; they use optical light to calculate distance and position. They are extremely inexpensive, extremely reliable and process information quickly.

A new technology that is out is LASER MOUSE. Instead of optical light, they use laser light to precisely calculate movement and position. They are extremely precise, reliable and process information extremely quick. Most gamers use Laser mouse because of their high performance. However they are much more expensive than optical mouse.

3.BARCODE READER: A barcode reader (or barcode scanner) is an electronic device for reading printed barcodes. Like a flatbed scanner, it consists of a light source, a lens and a photo conductor translating optical impulses into electrical ones. Additionally, nearly all barcode

readers contain decoder circuitry analyzing the barcode's image data provided by the photo conductor and sending the barcode's content to the scanner's output portA bar code scanner scans a little label that has a bar code on it.  The information is then saved on the computer.  Bar code scanners are used in libraries a lot.A barcode reader also called a price scanner or point-of-sale (POS ) scanner is a hand-held or stationary input device used to capture and read information contained in a bar code . A barcode reader consists of a scanner , a decoder (either built-in or external), and a cable used to connect the reader with a computer. Because a barcode reader merely captures and translates the barcode into numbers and/or letters, the data must be sent to a computer so that a software application can make sense of the data. Barcode scanners can be connected to a computer through a serial port , keyboard port , or an interface device called a wedge . A barcode reader works by directing a beam of light across the bar code and measuring the amount of light that is reflected back. (The dark bars on a barcode reflect less light than the white spaces between them.) The scanner converts the light energy into electrical energy, which is then converted into data by the decoder and forwarded to a computer.

4.SCANNERS

A scanner is a device that captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. Scanners come in hand-held, feed-in, and flatbed types and for scanning black-and-white only, or color. Very high resolution scanners are used for scanning for high-resolution printing, but lower resolution scanners are adequate for capturing images for computer display. Scanners usually come with software, such as Adobe's Photoshop product.Scanners usually attach to your personal computer with a Small Computer System Interface (SCSI ). Some major manufacturers of scanners include: Epson, Hewlett-Packard, Microtek, and Relisys.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, orthotics, gaming and other applications. Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical. A scanner is used to copy pictures or other things and save them as files on the computer. 

5.WEBCAMS

A webcam, or web camera, is the loosely used term for any camera that generates images that can be accessed by and displayed on the World Wide Web through a server. A webcam is essentially just a camera that is connected to a computer, either directly or wirelessly, and gathers a series of images for remote display elsewhere. Webcam technology is widely used by all sorts of people for all sorts of different reasons.

In 1991, the first webcam was up and running at Cambridge University's Computer Science Department, but since then, webcams have crept into homes, businesses, public streets and

buildings. Webcams are often used for personal use in the home by parents who want to give distant relatives visual access to their children or want to monitor what goes on in the home while they are at work. People might also use webcams in the home to keep an eye on things while they are out of town or even just to see what their pets do all day. The uses of a webcam are limitless. Businesses often use webcams for video conferencing, and webcam technology is used by numerous other entities to give the public access to a variety of information, from weather and traffic to the feeding habits of the most recently acquired zoo animal. Some schools and day care facilities use a webcam to allow parents to see what their children do at school.

The webcam basically works by capturing a series of digital images that are transferred by the computer to a server and then displayed to the hosting page. There are even sites that allow users to upload and store their webcam images for free, which many individuals choose for personal use. Some webcams capture a still image only once every 30 seconds, while others provide streaming video by capturing 30 images per second. A webcam can be purchased at any computer store and most major electronics retailers, as well as online.

6.DIGITAL PEN

A digital pen is a battery-operated writing instrument that allows the user to digitally capture a handwritten note or drawing. Typically, a digital pen comes with a Universal Serial Bus (USB) cradle to let the user upload the handwritten notes to a personal computer (PC). The pen looks like a regular ball-point pen and can be used as such, but requires special digital paper if the user wishes to digitally capture what he has written. A page of digital paper, which can be purchased in traditional pad or sticky-note size, has small dots on it that allow the pen to "see" what has been written.

Many digital pens come with handwriting recognition software that allows the user to import their handwritten notes into typed

text. Some of the newer high-end digital pens are wireless, taking advantage of Bluetooth technology. These pens do not require a docking station, but instead send the captured notes or drawings directly to the user's PC or cell phone. Typically, a digital pen can store up to 40 pages of saved digital paper in its memory. Only pages that have been checked will be saved. Most pens save the handwritten data as an image file (GIF or JPEG, depending on the pen's manufacturer) although some digital pens use a proprietary file format. When the user wants to upload his saved notes from the pen, he docks the pen in its USB cradle.

7.FINGER PRINT SCANNERThe fingerprint scanner is a form of biometrics which enables us to use something we have (in this case our finger) to help authenticate us to a computer or network.Fingerprint scanners are starting to show up in many mom and pop shops all over. They are cheap and easy to configure. They are mainly used to ensure security in business organizations. Along with finger print scanner, retina scan analysis is also used for security in organizations. Computerized fingerprint scanners have been a mainstay of spy thrillers for decades, but up until recently, they were pretty exotic technology in the real world. In the past few years, however, scanners have started popping up all over the place -- in police stations, high-security buildings and even on PC keyboards.Remembering passwords becomes inconvenient for most people, especially businessmen who need to protect, as well as access numerous high security systems, files, etc. With the fingerprint scanner, a user doesn’t even have to know what their password is and they can still access secure systems.

8.TOUCH SCREEN

A touch screen is a display which can detect the presence and location a touch within the display area. The term generally refers to touch by a finger or hand. Some touch screens can sense other passive objects, such as a stylus. However, if the object sensed is active, as with a light pen, the term touchscreen is generally not applicable. The rule of thumb is this: if you can interact with the display using just your finger, it is likely a touchscreen - even if you are using a stylus or some other object. If it does not work with just the finger, it is most likely not a touchscreen.The touchscreen has two main attributes. First, it enables you to interact with what is displayed directly on the screen, where it is displayed, rather than indirectly with a mouse (computing) or touchpad. Secondly, it lets one do so without requiring any intermediate device, again, such as a stylus that needs to be held in the hand. Such displays can be attached to computers or, as terminals, to networks. They also play a prominent role in the design of digital appliances such as the personal digital assistant (PDA), satellite navigation devices and mobile phone.

9.GAMING DEVICESA gamepad, also called joy pad or control pad, is a type of game controller held in the hand, 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. The direction controller has traditionally been a four-way digital cross (D-pad), but most modern controllers additionally (or as a substitute) feature an analog stick. The analog stick was introduced with the Nintendo 64 controller.

Gamepads are the primary means of input on all modern video game consoles except for the Wii (though the Wii Remote can function alternately as a gamepad). Gamepads are also available for personal computers, although a keyboard and mouse combination tends to be utilized more often for certain genres.

Some programmable joysticks that can be programmed to act as a key on a keyboard have been made to circumvent the problem lacking joystick support in some computer games, notably the Belkin Nostromo Speed Pad n52.

10.MICROPHONES

A microphone, sometimes referred to as a mike or mic (both pronounced / ̍ ma ɪ k/ ), is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal which is ultimately transmitted into the system. Microphones are used in many applications such as telephones, tape recorders, hearing aids, motion picture production, live and recorded audio engineering, in radio and television broadcasting and in computers for recording voice, VoIP, and for non-acoustic purposes such as ultrasonic checking.

The most common design today uses a thin membrane which vibrates in response to sound pressure. This movement is subsequently translated into an electrical signal. Most microphones in use today for audio use electromagnetic generation (dynamic microphones), capacitance change (condenser microphones) or piezoelectric generation to produce the signal from mechanical vibration.

Microphone covers are often made of soft open-cell polyester or polyurethane foam because of the inexpensive, disposable nature of the foam. Optional windscreens are often available from the manufacturer and third parties. One disadvantage of polyurethane foam microphone covers is that they can deteriorate over time. Windscreens also tend to collect dirt and moisture in their open cells and must be cleaned to prevent high frequency loss, bad odour and unhealthy conditions for the person using the microphone.

11.PADDLE A paddle is a game controller with a round wheel and one or more fire buttons, where the wheel is typically used to control movement of the player object along one axis of the video screen. A paddle controller rotates through a fixed arc (usually about 330 degrees); it has a stop at each end and rotating it further can break it.

A variation on the Paddle, the Atari driving controller appeared on the Atari 2600. Designed specifically for the game Indy 500, it was almost identical in operation and design to the regular paddle controller. However, its wheel can be continuously rotated in either direction, and it was missing the extra paddle included on the previous model. Unlike a spinner, friction prevented the wheel from gaining momentum.HOW IT WRKSThe paddle wheel is usually mechanically coupled to a potentiometer, so as to generate an output voltage level varying with the wheel's angle relative to a fixed reference position. A paddle is thus an absolute position controller. That is, the sensor can be read and the result directly indicates the position of the paddle knob. This is in contrast to a quadrature encoder-based device or "spinner".

12.JOYSITCKThe name "joystick" is thought to originate with early 20th century French pilot Robert Esnault-Pelterie. 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. A popular variation of the joystick used on modern video game consoles is the analog stick.Some joysticks have force feedback capability. These are thus active devices, not just input devices. The computer can return a signal to the joystick that causes it to resist the movement with a returning force or make the joystick vibrate. Most joysticks are two-dimensional, having two axes of movement (similar to a mouse), but three-dimensional joysticks do exist. A joystick is generally configured so that moving the stick left or right signals movement along the X axis, and moving it forward (up) or back (down) signals movement along the Y axis.Additionally joysticks often have one or more fire buttons, used to trigger some kind of action. These are simple on/off switches.Most interface cards for PCs have a joystick (game control) port. Modern joysticks mostly use a USB interface for connection to the PC.

Specialist joysticks, classed as an assistive technology pointing device, are used to replace the computer mouse for people with fairly severe physical disabilities. Rather than controlling games these joysticks plug into the USB port and control the mouse pointer. They are often useful to people with athetoid conditions, such as cerebral palsy, who find them easier to grasp than a standard mouse. Miniature joysticks are also available for people with conditions involving muscular weakness such as muscular dystrophy or motor neurone

disease.’

INDUSTRIAL USESIn recent times, the employment of joysticks has become common place in many industrial and manufacturing applications, such as; cranes, assembly lines, forestry equipment, mining trucks, and excavators. In fact, the use of such joysticks is in such high demand, that it has virtually replaced the traditional mechanical control lever in nearly all modern hydraulic control systems.Due to the abusive nature of such applications, the industrial joystick tends to be more robust than the typical video-game controller, and able to function over a high cycle life. This led to the development and employment of Hall Effect sensing to such applications in the 1980s as a means of contactless sensing. The leading manufacturer of Industrial Hall Effect Joysticks Is P- Q controls which was one of the first companies to expand the use of Hall Effect sensing to such applications in the 1980s, and in fact holds exclusive patents for contactless sensing.

13.TRACK BALL A trackball is a pointing device consisting of a ball housed in a socket containing sensors to detect rotation of the ball about two axes—like an upside-down mouse with an exposed protruding ball. The user rolls the ball with the thumb, fingers, or the palm of the hand to move a cursor. Large tracker balls are common on CAD workstations for easy precision. Before the advent of the touchpad, small trackballs were common on portable computers, where there may be no desk space on which to run a mouse. Some small thumb balls clip onto the side of the keyboard and have integral buttons with the same function as mouse buttons. The trackball was invented by Tom Cranston and Fred Longstaff as part of the Royal Canadian Navy's DATAR system in 1952, eleven years before the mouse was invented. This first trackball used a Canadian five-pin bowling ball.When mouse still used a mechanical design (with slotted 'chopper' wheels interrupting a beam of light to measure rotation), trackballs had the advantage of being in contact with the user's hand, which is generally cleaner than the desk or mousepad and doesn't drag lint into the chopper wheels. The late 1990s advent of scroll wheels, and the replacement of mouse balls by direct optical tracking, put trackballs at a disadvantage and forced them to retreat into niches where their distinctive merits remained important. Most trackballs now have direct optical tracking which follows dots on the ball. Some mice, in place of a scroll wheel, acquired a small trackball between the buttons, useful in maps and other circumstances calling for scrolling in two dimensions.Computer gamers have been able to successfully use trackballs in most modern computer games, including FPS, RPG, and RTS genres, with any slight loss of speed compensated for with an increase in precision. Many trackball gamers are competent at "throwing" their cursor rapidly across the screen, by spinning the trackball, enabling (with practice) much faster motion than can be achieved with a mouse and arm motion. However, many gamers are deterred by the time it takes to 'get used to' the different

style of hand control that a trackball requires. Trackballs have also been regarded as excellent complements to analog joysticks, as pioneered by the Assassin 3D 1996 trackball with joystick pass-through capability.Some computer users prefer a trackball over the more common mouse for ergonomic reasons. There doesn't seem to be conclusive evidence of one being better than the other in terms of comfort. Users are encouraged to test different devices, and to maintain proper posture and scheduled breaks for comfort. Some disabled users find trackballs easier since they only have to move their thumb relative to their hand, instead of moving the whole hand, while others incur unacceptable fatigue of the thumb.

14.MICR:Magnetic Ink Character Recognition, or MICR (pronounced my-ker or micker), a character recognition technology adopted mainly by the banking industry to facilitate the processing of checks. The process was demonstrated to the American Bankers Association in July 1956, and was almost universally employed in the U.S. by 1963. It employees a system of printed characters which can be easily read by human beings as well as machine readers. They are usually printed using a special ink which contains a magnatisable material and this printed material has 4 small gaps and 2 big gaps. When a character is subsequently read, it is passed beneath a reading head and the big and small gaps send different impulses as the input. This method is mainly used in the banking industry where most cheques are processed under MICR code. The data printed across the bottom of the cheque are recorded in the MICR form which can be read by the machine and acts as an input to the system to generate other details.

MICR characters are printed in the form of either an E-13B or CMC-7 Font.  Each font series is made up of a series of numbers and symbols specifically designed for readability on check sorting machines which read at extremely high rates of speed.  The symbols provide a beginning and ending point for each group of numbers allowing the machine to quickly determine what each series of number signifies. If required the same information in the document can also be read optically through OCR. Over the years, MICR has been proven to be a secure and high performance mechanism for processing information. The numbers typically found on the bottom of a cheque comprising of the cheque number, sort number and account number are usually printed in magnetic ink for use in MICR. The magnetically charged printing allows each character to be recognized based on the magnetic signal created by each character’s unique shape.  These shapes create a unique magnetic “fingerprint” which allows the reader-sorter machines to recognize each character.  Since MICR is a machine readable process, it is imperative that each character is accurately placed and is free of irregular marks or voids.  The uniformity of print is another key component to readability. 

15.OCR: OCR (optical character recognition) is the recognition of printed or written text characters by a computer. This involves photo scanning of the text character-by-character, analysis of the scanned-in image, and then translation of the character image into character codes, such as ASCII, commonly used in data processing. Optical character recognition (using optical techniques such as mirrors and lenses) and digital character recognition (using scanners and computer algorithms) were originally considered separate fields. Because very few applications

survive that use true optical techniques, the OCR term has now been broadened to include digital image processing as well.In OCR processing, the scanned-in image or bitmap is analyzed for light and dark areas in order to identify each alphabetic letter or numeric digit. When a character is recognized, it is converted into an ASCII code. Special circuit boards and computer chips designed expressly for OCR are used to speed up the recognition process. OCR is being used by libraries to digitize and preserve their holdings. OCR is also used to process checks and credit card slips and sort the mail. Billions of magazines and letters are sorted every day by OCR machines, considerably speeding up mail delivery. It also employees a set of printed characters with a standard form that can be read by humans and machines. The machine reading is done by light scanning techniques in which each character is eliminated by a light source and the reflected image of the character is analysed in terms of the dark light pattern produced. OCR also has the potential of reading hand – written documents. But, the OSR’s can read the characters that are written specifically using certain norms like proper – spacing, paper – quality, ink specifications, font type and the size of the characters. Large volume building applications like credit card organizations increasingly use OCR methods.

16.VOICE RECOGNITION:The field of computer science that deals with designing computer systems that can recognize spoken words. Note that voice recognition implies only that the computer can take dictation, not that it understands what is being said.

Comprehending human languages falls under a different field of computer science called natural language processing. A number of voice recognition systems are available on the market. The most powerful can recognize thousands of words. However, they generally require an extended training session during which the computer system becomes accustomed to a particular voice and accent. Such systems are said to be speaker dependent. Many systems also require that the speaker speak slowly and distinctly and separate each word with a short pause. These systems are called discrete speech systems. Recently, great strides have been made in continuous speech systems -- voice recognition systems that allow you to speak naturally. There are now several continuous-speech systems available for personal computers. Because of their limitations and high cost, voice recognition systems have traditionally been used only in a few specialized situations. For example, such systems are useful in instances when the user is unable to use a keyboard to enter data because his or her hands are occupied or disabled. Instead of typing commands, the user can simply speak into a headset. Increasingly, however, as the cost decreases and performance improves, speech recognition systems are entering the mainstream and are being used as an alternative to keyboards.

17.CARD READER:A card reader is a device that is capable of reading the encoding on plastic cards. It is also known as a device on a photocopier that reads a cards barcode, enables the service and deducts credit as the card is used. Known as an Input device on a card terminal, it translates the information stored on the magnetic stripe on the back of a

card. It has a slot for the memory card on which the pictures in a digital camera are stored and quickly transfers the pictures to your computer. It is a device typically having a USB interface, for accessing the data on a memory card such as a Compact Flash, secure digital or Multimedia Card. It is also known as a hardware device that reads and transmits payment information stored in the magnetic stripe on a credit, debit or stored-value card. It is a device that inserts flash memory cards to transfer the data to the computer. Much faster than the serial port!

Features: Read and write memory cards. Supports Memory Stick PRO, Memory Stick, SD

Memory Card, Multimedia Card and xD-Picture Card. Supports, with your card adapter, Memory Stick

Duo™, Memory StickMicr, miniSD, microSD, RS-MC, MMCplus, MMCmobile

Plug-and-play, no drivers required.

No batteries required, powered via ExpressCard/34 slot.

USB 2.0 High-Speed (up to 480 Mbps) compared to up to 12 Mbps for USB 1.0 card readers and even slower rates transferring directly from the camera.