Input and Output

1. Input and Output The User Connection

2. Input-Getting Data From the User • Some data such as a scanned bar code or speech that is spoken to the computer can go directly for processing • Some input must go through intermediate handling such as translating a source document into machine readable data

3. Keyboard • Standard keyboards are common input devices on computers • Specialized keyboards exist such as fast food restaurant ordering systems • Cordless keyboards use a battery powered transmitter instead of a cord to transfer data to the computer • Ergonomic keyboards are specially designed for a natural position of the hands

4. Ergonomics • A field of study concerned with healthy, comfortable, efficient interactions between people and machines • RSI-repetitive strain injury can be sustained from doing the same thing over and over such as typing. Ergonomically designed keyboards can lessen these injuries

5. Pointing Devices • Allows user to point, set the insertion point, or click something to issue a command • Mouse • Mechanical • Optical • Cordless

6. Other Pointing Devices • Trackball -variation on a mouse where you move the ball and the device stays still • Touchpad -pressure sensitive area that you physically touch to give commands; common on laptops • Joystick -lever with a handgrip

7. Even More Pointing Devices • Graphics Tablet or Digitizing Tablet- invisible grid of electronic dots that are activated by a pen-like stylus or a puck • Touch screens - beams of light emitted from edge of screen can determine when a user touches the screen by the broken beams or can use a light pen • Pen based computing -uses a stylus to select items; common in handheld devices

8. Source Data Automation • Use of special equipment to collect data at its source • Does not require re-keying which eliminates mistakes • Three primary areas: • Magnetic Ink Character Recogniton (MICR) • Scanners • Other Optical Methods

9. MICR • Uses a machine to read characters written in an ink made of magentized particles • Common example is check numbers at the bank • MICR inscriber writes information using the special ink

10. Scanners • Optical scanners, now just scanners, convert text or drawings into machine readable format • Using Optical Recognition, a light beam scans the item and changes it into electrical impulses for processing • Common example is the bar code reader

11. Document Imaging • Process of converting paper copies to computer copies • Can be stored on disk instead of file cabinets • Less expensive • More efficient

12. Types of Scanners • A flatbed scanner scans one sheet at a time by laying the sheet face down on the bed of the scanner • Sheetfed scanner use motorized rollers to feed the document across the scanning mechanism • Handheld scanner-portable device that requires users to pass the scanning element over the item to be scanned

13. More Optical Recognition Methods • Optical mark recognition (OMR)- searches for and recognizes marks such as a scantron test • Optical Character Recognition (OCR) – uses a wand reader to scan and process standardized letters (OCR-A) many times on things such as sales tags

14. Some More Optical Recognition Methods • Bar codes-each product has a unique product code (UPC) represented by a pattern of bars • Bar code scanner scans the bars using reflected light which is then processed to retrieve product information assigned to that bar code • Handwriting Recognition

15. Voice Input • Also called speech recognition • Speech accepted through microphone and converted into binary • Can be used to control the operation of the computer or to enter data through dictation

16. Two Types of Speech Recognition • Discrete word systems-limited number of recognized words; must pause between words; very accurate • Continuous word systems-allows almost normal rate of speech and recognizes many more words; less accurate; comes in some of the newer application software packages such as Office XP

17. Digital Cameras • Image is stored on a chip in the camera • Can be viewed immediately without processing • Pixels-tiny dots that compose a digital image • Resolution measures the quality of the images by the number of pixels per inch • Many use removable flash cards for storage • Images must be downloaded to a computer by connecting the camera to the computer and transferring the images

18. Digital Video • Consists of a series of still images or frames • Can be captured by an inexpensive web cam • Video capture cards allow you to translate TV and older video into a format your computer can recognize • Newer video cameras actually record the video digitally which allows you to transfer video straight to the computer

19. Output : Information for the User • Most common form is output to the screen or printer • Other types include voice, sound, graphics and even smells

20. Screen Technology • Screen is part of the monitor, the housing which also holds the electrical components • Screen output is known as “soft copy” because it is not permanent • “Hard copy” like a printout, is tangible

21. CRT • Stands for cathode ray tube • Most common variety of monitor • Most are color but some are monochrome, meaning they can only show one color (usually yellow or green) • Monochrome are less expensive and used in some business environments

22. How the CRT works • Uses a technology called raster scanning • An electron beam sweeps across the back of the screen covered in phosphorous that glows when hit by light • It doesn’t glow very long so it must be refreshed • The scan rate is the number of times the screen is refreshed, generally 75 times per second in a quality monitor

23. More on the monitor • Monitor is divded into dots that are individually addressable and can be set to glow at a certain brightness and a certain color • Dots are called picture elements or pixels.

24. Quality of a monitor • Resolution on a screen is measure of screen clarity and is related to the number of pixels on the screen • Higher resolution = more pixels • Dot pitch is the space between pixels • Smaller dot pitch=sharper image

25. Graphics Cards • The Control Unit of the CPU controls the signals sent to the monitor via the graphics card or the graphics adapter board • The card is plugged into an expansion slot on the motherboard

26. Standards for Monitors • Standards were developed early to define resolutions and colors • Most common standard today is SVGA (Super Video Graphics Adapter) • Supports a variety of resolutions and over 16 million colors

27. Video Memory • High speed form of RAM installed on the graphics card • Allows more colors to be displayed on the screen at once • Separate from main memory and stores the image temporarily from the CPU

28. Is bigger better? • The size of a CRT is called the VIS, viewable image size • Not necessarily the spec given at the computer store. A 17” monitor may only have a 16” vis • In other words, it measures across the screen diagonally and only includes the glass part • More expensive • Takes up more space • Easier on eyes • Good for graphics

29. Flat panel screens • LCD or liquid crystal display is used commonly on small devices such as cell phones • Getting larger and starting to appear in the desktop market • Flat panels maintain their “skininess” even as the screen grows in size unlike CRT which grow deeper as size increases

30. Flat Screen Technology • Active matrix-based on TFT (thin flim transistor) • Passive matrix uses fewer transistors but produces a brighter image • Gas plasma a newer more expensive technology with screen sizes up to 60 inches

31. Smart Displays • Based on flat panel technology • Runs Windows CE • Touch screen • Allows users to access other computers • Contains own wireless transmitter and processor

32. Printers • Produce output on paper • Two modes: • Landsacape • Portrait • Two types of printers: • Impact • Non-impact

33. Impact Printers • Print device actually touches or impacts paper • Line printers-fast printers usually associated with mainframes. • Dot-matrix printers-can print through mulitple forms • Overall, slower, lower quality, and don’t last as long

34. Non-impact printer • Print device doesn’t actually touch the paper • Generally more expensive • Higher quality graphics • Generally faster than impact printers

35. Laser printers • Non-impact printer that uses light to transfer image to paper • Normal print 8-10ppm • Network print 35-50ppm • High end printers print up to 1,000 ppm • High quality, usually 600-1200dpi • Color laser printers much more expensive

36. Inkjet Printers • Spray ink onto page • Slower than laser • Generally lower quality • However, affordable color printing at pretty good quality • Three colors combine to make all colors • With inkjet and laser, can result in some colors not true color of image

37. Voice Output • Speech synthesis allows computer to produce speech as output • Voice synthesizers, aka voice output devices or audio response units transfer data in storage to recognizable speech

38. Two types of synthesis • Synthesis by analysis-replays recorded human speech as needed. Sounds natural but pace is sometimes awkward • Synthesis by rule-creates artificial speech that does not sound like a real human

39. Music output • MIDI-Musical Instrument Digital Interface • Allows musical instruments and synthesizers to be connected to computer • Shares data with computer regarding pitch, length of notes, volume and other musical attributes

40. Microform • Computer Output Microform produces small images on microfiche or microfilm • Microfilm is a roll or images • Microfiche more resembles a card • Can store up to 1,000 images per roll or fiche

41. Combining Input and Output • Terminal-combines input and output, usually monitor and keyboard • Dumb terminal-has no processing abilities and just sends data back and forth to another computer • Intelligent terminal-keyboard, monitor, memory and processor that can perform its own processing • POS or point of sale terminal used mainly in retail markets. For example, in grocery store bar code scanner with display monitor, receipt printer

42. Computer Graphics • Business graphics-charts, graphs, and maps • Allow visual presentation of data • Easy to spot trends and make decisions

43. Video Graphics • Graphics associated with moving images • Animations • Special Effects • Video games

44. CAD/CAM/CIM • Computer Aided Design • Computer Aided Manufacturing • Creates two and three dimensional models • Designs products and allows for theoretical testing by software • CAM controls production process • Computer Integrated Manufacturing is the integration of both CAD and CAM