Computer Sciences: 2010

Introduction

Posted by farooq

Posted by farooq

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Plotter

Posted by farooq

Plotter
is an important output device. Used to print high quality graphics and drawings. Although the graphics can be printed on printers, the resolution of such printing is limited on printers. Plotters are generally used for printing/drawing graphical images such as charts, drawings, maps. Of engineering and scientific application.

Some important types of printers are:

a.) Flat Bed Plotters:
These plotters print the graphical images by moving the pen on stationary flat surface material. They produce very accurate drawings.

b.) Drum Plotters:
These plotters print graphical images by moving both the pen and the drum having paper. They do not produce as accurate drawings as printed by flat bed plotters.

c.)Inkjet Plotters: These plotters use inkjet in place of pens. They are faster than flat bed plotters and can print multi-colored large drawings

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Plotter

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Data Scanning Devices

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Optical Recognition System:

Optical Recognition System provide another means of minimizing keyed input by capturing data at the source. These systems enable the computer to “red” data by scanning printed text for recognizable patterns.

The banking industry developed one of the earliest scanning systems in the 1950’s for processing cheque. The Magnetic link Character Recognition (MICR) system is still used throughout the banking industry. The bank, branch, account number and cheque number are encoded on the cheque before it is sent to the customer. After the customer has used the cheque and it comes back to the bank to the bank, all that needs to be entered manually is the amount. MICRO has not been adopted by other industries because the character set has only fourteen symbols.

Bar Code Reader:

Of all the scanning devices, you are probably most familiar with BAR CODE READES. Many retail and grocery stores use some from of bar code reader to determine the item being sold and to retrieve the item price from a computer system. The code reader may be a handled unit or it may be embedded in a countertop. The bar code reader reads the Universal Product Code(UPC), a pattern of bars printed on merchandise. The UPS has gained the use of the code because the system was used to check their accuracy and speed. Today, bar codes are used to update inventory and ensure correct pricing. Federal Express employees can usually tell a customer within a matter of minutes the location of any package.

Optical Mark Reader:

By taking exams, you are familiar with Mark Sense Character Recognition systems. Every time you take a test with a “fill in the bubble” Scranton from and use a #2 lead pencil, you are creating input suitable for and OPTICAL MARK READER (ORMO. A #2 lead pencil works best because of the number of magnetic particles in that weight lead. The OMR sense the magnetized marks, enabling the reader to determine which responses are marked.

Optical Scanners:

Can scan typed documents, pictures, graphics or even handwriting into a computer. Photographs scanned into a microcomputer appear clearly on the screen and can be displayed whenever desired. The copy that the computer stores never yellows with age. Early scanners could recognize only text printed in a special OPTICAL CHARACTER RECOGNITION(OCR) typeface. A scanner converts the image that it sees into numeric digits before storing it in the computer. This conversion process in known as DIGIZING.

Depending on the volume and type of material to be scanned, you can use drum scanner, flatbed scanner, sheeted scanner and even small handheld scanners. The small, hadheld scanner sheeted scanners(priced at about $150) are used most frequently with micro microcomputer; however, only 5 per cent of all microcomputer systems are equipped with scanners. Manufacturers responded to user reluctance to use scanners by releasing in 1995 a number of new, small paper scanners priced between $500 and $700.) most of these new devices sit between the keyboard and the monitor and can interface with a fax machine, send e-mail, and store documents on disk for archive purposes.

Digitizer:

Digitizer is used to create drawing and pictures using a digitizer tablet by a process called digitizing. Digitizing is a process by which graphic representations are converted into digitizer consist of 3 main parts – a flat surface called tablet, a small hand held mouse-like device called puck and a special pen like device called stylus. The puck is used to input existing drawings into the computer. The stylus is used to trace exiting drawing placed on the tablet. The user makes contact to the tablet with stylus. As the stylus is connected to the tablet by a write, the traced image is stored in RAM and displayed on the monitor.

Electronic Card Reader:

Before discussing electronic card reader, let we discuss electronic credit cards. Electronic credit card make it possible to charge online payments to one’s credit card account. It is card details can be encrypted by using the SSL. Protocol in the buyer’s computer, which is available in standard browsers. The number of input devices are common in association with ash transactions. The most common are ATMs and POS terminals.

1. ATM:

Automatic Taller Machine are interactive input/output devices the enable people to make bank transactions from remote locations. ATMs utilize screen input as well as magnetic card readers.

2. POS:
Point of Sale: terminals are computerized cash registers that also often incorporate touch screen technology and bar-code scanners. These devices allow the input of numerous data such as item sold, price, method of payment, name or Zip code of the buyer, and so on. Some inputs are automated; others may be entered by the operators.

Vision Input System:

Are the latest input devices that can recognize the vision/image which appears in the range of its lens. It seems to be vary useful and are becoming popular in different Got. Departments like licensing, passport department and other authorities where personal identification is required.

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Keyboard Devices

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Keyboard Devices:

Most input data is entered input the computer by using a keyboard. This input methods is similar to typing on a typewriters.

Most typewriters and computer keyboards are Qwerty Keyboards. The alphabetic keys are arranged so that the upper-left row of letters begins with the six letters QWERTY. Designers of other keyboards claim that their boards are easier to learn than the QWERTY keyboard.

Computer keyboards

Include keys that are designed to perform specific tasks. These special keys include function keys, directional keys and special-purpose keys such as Alt, Ctrl, Enter, Ins, and Esc. These keys enable the user to perform complex tasks easily when using the application.

Some of keyboards have even 112 keys, with three new keys designed to simplify worki

ing with Windows 98. two of these keys, next to the Alt key, bring up Start menu. The third key, next to the right Ctrl key, brings up a menu of functions that are frequently accessed in whichever application is currently being used.

Point and Draw Devices : Many people use devices instead of keyboards whenever possible. Pointing devices minimize the amount of typing (consequently, the number of errors). The many pointing devices available include the mouse, trackball, light pen, digitizing tablet, touch screen and pen-based systems.

The Mouse and Track Ball: The mouse is a palm-size device with a ball built into the button. The mouse is usually connected to the computer by the cable (computer wires are frequently called cables) and many have from one to four buttons (usually two). The mouse may be mechanical or optical and comes in many shapes and sizes. When you move the mouse over a smooth surface, the calls rolls, and the pointer on the display screen moves in the same direction. The Apple Macintosh, with its graphical user interface, made the mouse popular. Now, most microcomputer systems, regardless of the manufacturer, use a mouse. With the mouse, you can draw, select options from a menu and modify or move text. You issue commands by pointing with the pointer and clicking a operating a microcomputer easier for beginning users.

Touchpad:

The touch pad is a stationary pointing devices that people find less tiring to use than a mouse or a track ball. The movement of a finger across a small touch surface is translated into cursor movement on the computer screen. The touch sensitivity surface may be just 1.5- 2 inch square, so the finger does not have to move much. Its size makes it most suitable for the notebooks or the laptops.

A device

That was released in 1995 enables the user to move the cursor using and infrared pen. The pen is cordless and works when it is as fifteen feet from the screen. Although the mouse is still the most pointing device, these innovations may change that in future.

Joysticks:
A joysticks is a pointing device often used for playing games. The joystick has a gearshift-like lever that is used to move the pointer on the screed. On most joysticks, a button on the top is used to select options. In industry and manufacturing, joysticks are used to control robots. Flight simulators and other training simulators also use joysticks.

Touch-Sensitive Screens:

Perhaps the easiest way to enter data is with the touch of finger. Touch screens enable the user to select and option by pressing a specific part of the screen. Touch screens are commonly used in grocery stores, fast-food restaurants and information kiosks.

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