Input & OutputPart I Bayram Güzer
Input & Output • Users submit input data to the computer to get processed information • Sometimes the output is an instant reaction to input • Bar codes on supermarket provide input that permits instant retrieval of outputs that is price and item name • Input and output may be separated by time or distance • Data on checks is used as input to the bank computer, which eventually process the data to prepare a bank statement once a month • Although diversity of computer applications may differ for the time or distance of input and output, the process is the same; input, processing and the output
Input • There are two main types of input method. • Data can go directly to the computer for processing • Bar-codes, speech through microphone. • Data goes through an intermediate handling • Original data is hand written, it is translated to a medium that a machine can read • Using keyboard to write in electronic form • Some of the common input devices are • Keyboard • Pointing Devices • Source Data Automation
Keyboard • Keyboard is the most common device for transferring user input to the computer system • It is similar to a typewriter keyboard and it is one of the primary part of a personal computer • There are two main types of keyboards; • Alphanumeric keyboards • Special-function keyboards
Traditional Alphanumeric Keyboards • Most widely used keyboards are alphanumeric keyboards • Alphanumeric keyboards usually have 101-key with QWERTY key layout. • 12 function keys • A numeric keypad • Variety of special function keys • Dedicated cursor keys
Traditional Alphanumeric Keyboard First keyboard layout introduced by the IBM as 101-key
Traditional Alphanumeric Keyboard • Escape (ESC) key is often used to “escape” from the program • Usually it works on dialog boxes. • Tab key is used for different purposes. • In word processing software, it is used to moves the insertion point to the next tab stop. • In spreadsheet applications, it is used to move the cursor to the next cell. • In dialog boxes or menus, it is used to highlight the next button or option.
Traditional Alphanumeric Keyboard • When Caps Lock (Caps) key is pressed, uppercase letter is produced. • Shift key allows us to produce the upper symbols shown on the keys. It is used with other keys. • In addition, when you press any key with shift key, it either uppers or lowers the keys according to the state of the Caps Lock.
Traditional Alphanumeric Keyboard • Control (Ctrl) key is used with the combination of other keys. • Control key has different function depending on the program. • E.g. Ctrl + C is used for copying the file or text in Windows. • Alternate key (Alt) is also used in combination with other keys to initiate commands. • E.g. ALT + 1 is saves the file while you are working with it.
Traditional Alphanumeric Keyboard • Backspace is most often used to delete a character at the left of the cursor by moving the cursor back one position. • Enter key moves the cursor to the beginning of the next line.
Traditional Alphanumeric Keyboard • In addition to these special keys, main keyboard also have letters, numbers and some special symbols. • Function keys are used to give certain commands to the computer but the command is defined by the particular software. E.g. F12 opens Save As dialog box.
Traditional Alphanumeric Keyboard • Navigation keys helps you to navigate the document. Home and End moves the cursor to the beginning and end of a document. • Page Up and Page Down move the cursor to the previous and the next page. • Arrow keys allows you to move the cursor in four direction which is left, right, up and down. • It is also used in selecting menu items.
Traditional Alphanumeric Keyboard • Print Screen key causes image of the currently displayed screen to be placed on the computer’s clipboard that is a memory place which it can be saved or moved. • Insert (Ins) key is used to switch between two modes of entering data which is text-insert and typeover. • Delete (Del) key is used to delete a character or space at the right of the cursor.
Traditional Alphanumeric Keyboard • In addition to print screen, there is two keys which was empty when this keyboard layout first created. • These two keys are scroll lock and pause break. • Scroll lock key is used to toggle on/off the scroll lock feature. It is used to controls the cursor control keys for some programs but many applications ignore the scroll lock setting. • Last key is Pause/Break and it can temporarily freeze data that is being scrolled in the screen. Usually it works in the command prompt mode.
Ergonomic Keyboards • Designed to reduce or minimize repetitive strain injury of wrists. • Provide more neutral, comfortable position of wrists, arms, and hands.
Special Function Keyboards
Special Function Keyboards • Some keyboards are designed for special applications • Cash-register terminals at most fast-food restaurants • There are keys with name of the products and when it is pressed, product is put to the record of sale • Special function keyboards are also called as Point-of-Sale keyboards.
Pointing Devices • Pointing devices are used to position a pointer on the screen. • Communication with the operating system is handled by buttons. • When you click a button, commands are arriving to operating system • Some of the common pointing devices are; • Mouse • Trackball and Track pad • Joystick • Others
Mouse
Mouse • There are several types of mouse technology • Mechanical: small ball on underside rolls as mouse is moved. • Optical: uses a light beam to monitor mouse movement. • Cordless: uses either infrared or radio waves, rather than a cord, to connect to computer.
Mouse • A most common type of mouse has a ball on its underside. • It is rolled on a flat surface either on the desk which the computer sits or a flat item called as mouse pad. • The rolling movement causes corresponding movement of a pointer on the screen.
Mouse • The pointer can be in number of shapes but mostly it is in arrow shaped. • A common mouse has two buttons that is the left one and the right one. • Left button is used for common actions. • Right button is used for operating system or application-defined actions.
Mouse • Left button is usually used for clicking, double clicking purposes. • Right button is usually used for menus defined by the each application. • Today, mouse has multi-buttons which has different actions defined by a special software. • In addition, there is a wheel between the two buttons on a mouse which is used for scrolling the text or zooming in or out when you are viewing an image.
Trackball
Trackball • In trackball, there is a ball inset in a small external box. • The ball is rolled with the fingers and then it causes movement of the cursor. • Sometimes it is also called as upside-down mouse. • It is invented for the problems of travelers on the unavailability of flat surfaces.
Track pad • Track pad is another variation of the track ball. • You use your fingers in order to move the cursor. • There is two tabs at the bottom of the track pad which is used as left button and right button as on the mouse. • You can also use the track pad area for double clicking or single clicking.
Joystick • Joystick is a vertical stick that moves the mouse cursor in the direction stick is pushed. • Pressing buttons activates some actions to take place • It is mostly used for games.
Other Pointing Devices • Graphics tablet (Digitizer tablet and pen) • Consist of a pen and a touch sensitive tablet whose X – Y coordinates correspond with those on the computer’s display screen. • User moves stylus or puck across board • Used to create or trace precise drawings • Touch screen • Allow user to touch items on screen • Position of finger on screen determines item to be input into system • Used at kiosks in public places such as malls, bank atms.
Other Pointing Devices • Pen-based computing • Use pen-like stylus to input data to the touch sensitive displays • Often used in PDAs or pocket PCs
Source Data Automation • Used for efficient data input by reducing the number of intermediate steps requiring between the origination of data and its processing. • Data should be input as fast as possible for processing. • E.g. bar-code readers • Used with special equipment to collect data at the source • Primary types of source data automation are • Magnetic-ink character recognition (MICR) • Optical recognition devices • Other sources
Magnetic-Ink Character Recognition • Magnetic-Ink Character Recognition is abbreviated as MICR • It uses a machine to read characters made of magnetized particles • The most common use is in the numbers at the bottom of the checks. • The machine that prints magnetized characters is called as MICR inscriber. • Magnetized characters are preprinted on lower left-hand side of the check.
Optical Recognition Devices • Uses a light beam to scan data and convert electrical signals • Common uses are; • Bar-code readers at supermarkets • Scanners for graphics and documents • Document imaging; converts paper documents to electronic documents • It allows us to edit or process electronic documents by software
Scanners • Scanners can convert text or even a drawing or picture into computer-recognizable data by using a form of optical recognition • In the old times, people were transferring an existing document into the computer by retyping it. • Imaging is the process of converting those papers to an electronic version which you can store them on disk and retrieve when needed.
Scanners • Scanners are divided into three categories • Flatbed scanner • Sheetfeed scanner • Handheld scanner • Flatbed scanner • Typically scans one page at a time • It takes a space on your table • You can scan bound documents, pages from books and other bulky items.
Scanners • Sheetfeed scanner • motorized rollers feed the sheet (page) across the scanning head. • They are compact that is designed to feet between keyboard and the monitor • Handheld scanner • It is the least expensive and the least reliable out of the three • It provides you a handy portable option • Since it is handheld, the user must move the scanner in a straight line at a fixed rate • This makes it difficult to get good scan
Optical Character Recognition • Optical Character Recognition (OCR) software is used to scan the text in editable format using word processing. • One of the important characteristics of the OCR software is they can identify the individual letters as opposed to treating the entire document as one big picture. • Most scanners come with an OCR software.
Optical Mark Recognition • Optical Mark Recognition (OMR) senses marks on a piece of paper. • It is used to score certain tests. • Using a pencil, you make a mark in a specified box, the answer sheet is then graded by an optical device that recognizes the patterns and converts them to computer recognizable electrical signals. • E.g. Evaluation of your answer sheet for OSS.
Optical Character Recognition • OCR devices also use a light source to read special characters and convert them into electrical signals to be sent to the central processing unit. • A standard typeface for optical characters is called as OCR-A. • The handheld wand-reader is a popular input device for reading OCR-A. • It is increasingly used in hospitals, libraries, factories and in retail stores.
Optical Character Recognition • Hand-held scanner is using OCR technology and it can translate text from one language to another language. • Just slide the tip of the pen across the text and the translation appears in the pen’s window.
Bar-Code Reader • Each product on the store shelf has its own unique number which is part of the Universal Product Code (UPC). • This product number is coded on the product label by a pattern of vertical marks, or bars which is called as bar-codes. • These vertical patterns (bar-codes) are read by bar-code reader. • The bar-code contains a number which this number is stored in a computer database and provides the price. • Bar coding is an inexpensive and a reliable way.
Other Sources (Voice Input) • The user speaks into a microphone. • A chip on a board inside the computer analyzes the waveform and changes it to binary numbers • These digits are compared with the numbers in a stored vocabulary list. • If a match is found, the corresponding word is displayed on the screen.
Other Sources (Voice Input) • Voice input or speech recognition is another form of source input. • Speech recognition devices accept the spoken word through a microphone and convert it into binary code (0s and 1s). • It is used in by “busy hands” people, hands too dirty people and also people who doesn’t has access to keyboard.
Other Sources (Voice Input) • Changing radio frequencies in airplane cockpit and also physically disabled users are two of the common usage of this speech recognition systems. • Most speech recognition systems are speaker dependent. • Systems “learns” user’s voice.
Other Sources (Voice Input) • There are two types of main speech recognition systems. • In discrete word systems user must pause between words. • In continuous word systems users can speak normally.
Other Sources • Digital Cameras • Take photos, transfer it to computer, edit photos • Video Input • Usually used in security systems • Eye Recognition Systems • Face Recognition Systems • Fingerprint Recognition Systems
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