Connecting I/O Devices to the Computer

 Input and output devices must be connected to the computer before they can be used.


 Plug the device into an existing socket or port on the back of the computer.
 Install an expansion card with the port you need included on the back of the card.
 Connect wireless.

 Input devices enable you to input data and commands into the computer.
 The most common input devices are the keyboard and mouse.
 Other types of input devices include trackball, joystick and wheel, pointing stick, graphics tablet, touch display screen, stylus, voice recognition devices, touchpad, scanner, digital camera, video input, and biometric input.
 To maintain a permanent copy of data, you should store it on some type of storage medium.
 The three categories of storage media are magnetic storage, optical storage, and solid-state storage.
 Monitors and printers are examples of output devices.
 Monitors produce soft copy.
 Printers are used to produce a paper or hard copy of the processed result.
 Criteria for selecting a printer include speed, print quality, and cost.
 Input and output devices must be physically connected to the computer.
 Some input devices communicate with the computer through a physical connection.
 Wireless devices communicate with the computer through infrared or radio waves.

Input and Output Devices
 Input devices enable a user to input data and commands to the computer to be processed.
 Output devices enable the computer to give or show you the results of its processing.
 Some devices can perform both input and output operations.

Input Devices—The Keyboard


o The keyboard is the most widely used input device.
o As you press keys on the keyboard, an electrical signal representing that key is sent to the computer.

Keyboards are divided into sections.
 Typewriter keys: The standard alphabetic and numeric characters you would find on a typewriter
 Function keys: Special keys that perform some specific function for the application being run
 Numeric keypad: Used for mathematical operations
 Directional keys: Used to move the cursor around the screen

Input Devices—The Mouse

 The mouse is a pointing device that rolls around on a flat surface and controls the location of the pointer on the screen.

The mouse performs the following functions:
 Pointing: Placing the on-screen pointer at a specific place
 Clicking: Pressing and releasing the mouse button
 Dragging: Holding down the mouse button and dragging an object to a new location by dragging the mouse
 Double-clicking: Pressing and releasing the mouse button twice very quickly
 Right-clicking: Pressing the right mouse button

Other Pointing Devices
Other devices that control the on-screen pointer:
 Trackball: This is like a mouse turned upside down. You roll a ball around with your fingers to control the location of the pointer.
o These frequently are found on notebook computers.



 Joystick and wheel: Joysticks consist of a metal or plastic handle mounted on a base that you can move in any direction to move the pointer or other object.


o These typically are used for video games.
o Most have buttons that can be pushed or clicked to control input/output.
 Pointing stick: A pressure-sensitive device that resembles a pencil eraser; found mostly on notebook computers
 Graphics tablet: A flat drawing surface connected to the computer
o The user draws on the surface, and the figures or writing on the tablet can be input to the computer for processing.
 Touch display: Screens that contain pictures or shapes that the user can press to input that data
 Stylus/digital pen: Used with mobile devices to input data
 Touchpad: Used mostly in laptop/notebook computers
 Audio/voice input: Inputting sound and/or voice
o These usually require a microphone and special voice recognition software to be installed on the computer.
 Scanners: Devices that can convert a graphical image into a digital image and input it to the computer
o Types of scanners include
o Image scanners for scanning images and text
o Bar code scanners to read product bar codes
o Magnetic scanners to read the magnetic strip on a credit card

 Digital cameras: Used to take pictures and store them on a magnetic disk instead of on film
o Their images can be input directly into the computer.
 Video input: Input from a camcorder or VCR using video capture cards

 Biometric input: Uses fingerprint, face, handwriting, and voice for identification



Magnetic Storage Devices
 Floppy disks: Small, portable disks that hold a limited amount of data
 Hard disks: Large-capacity and fast-access storage devices
 Zip disks: Auxiliary storage devices that can hold large quantities of data and can be portable
 Magnetic tape drives: Used for making system backups and storing large quantities of data

Optical Storage Devices
 CD-DA: Audio CD
 CD-R: This drive allows you to read and to write to a compact disk
 CD-ROM: Can hold large amounts of data, but is read-only access



 CD-RW: Can be written on several times
 DVD-ROM: Read-only DVD format
 DVD-R: Similar to CD, but holds more data; read-only
 DVD-RW: Can be written on several times
 PhotoCD: Used for storing digital photographs on a CD

Solid-State Storage Media

 Non-volatile removable media
 Miniature mobile media
 Uses integrated circuits
 USB flash drive
 Connects to the computer via a USB port

Caring for Storage Media
 To safeguard your data from damage, follow these tips when dealing with removable media:
 Keep away from magnetic fields.
 Avoid extreme temperatures.
 Never try to disassemble the case.
 Remove media from drive when not being used.
 Tips for dealing with storage media (cont.)
 Write-protect important data.
 Hold optical disks at their edges.
 Never remove the media from the drive if the access light is on.
 Keep disks in a sturdy case when transporting them.

Output Devices—Monitors
Monitors are used to display video output to a user.
 Monitors may be monochromatic or color.
 Monochromatic monitors display output in a single-color display.
 Factors that influence the quality of a monitor
 Screen size: The diagonal measurement in inches of the display area
 Resolution: The number of pixels that can be displayed in the display area
 Dot pitch: The distance between each pixel in the display area

Typical Computer Monitor
 A typical computer monitor on a swivel stand that can be adjusted for viewing comfort.




Output Devices—Printers
 Printers are used to create a hard copy of a document or image.
 Printers vary by speed, quality, and price.

The most popular types of printers are
 Laser: Produce images using the same techniques as copier machines
 Ink jet: Use fine nozzles to spray ink onto the page as the paper passes through
 Dot matrix: Work similarly to a typewriter in that ink is transferred to the paper by some part of the printer striking a ribbon to transfer an image

Laser Printer

Ink Jet Printer


Other Types of Output Devices
 Speakers and headsets
 Fax machines and fax modems
 Multifunctional devices
 Contain a variation of output options
 Data projectors