Saturday, 6 April 2013

week 2

Storage Devices,I/O Devices&Other peripheral Devices

What is Input?
The keyboard
Pointing devices

Game controllers
Digital cameras
Voice input
Video input
Scanners and reading devices.optical scanners
optical readers
bar code readers
magnetic stripe card readers
Biometric input

What is output?
display devicesprinters
other output devices
type of storage

Input is the term denoting either an entrance or changes which are inserted into a system and which activate/modify a process. It is an abstract concept, used in the modeling, system(s) design and system(s) exploitation. It is usually connected with other terms,e.g., input field, input variable, input parameter, input value, input signal, input port,input device  and input file
In computing, a keyboard is a typewriter -style keyboard which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches. Following the decline of punch cards and paper tape, interaction via teleprinter-style keyboards became the main input device  for 
pointing device is an input interface (specifically a human interface device that allows a user to input spatial (i.e., continuous and multi-dimensional) data to a computer. CAD systems and graphical user interphrases (GUI) allow the user to control and provide data to the computer using physical gestures surface of the physical desktop and activating switches on the mouse. Movements of the pointing device are echoed on the screen by movements of the pointer (or cursor) and other visual changes.
A mouse is a small handheld device pushed over a horizontal surface.
A mouse moves the graphical pointer by being slid across a smooth surface. The conventional roller-ball mouse uses a ball to create this action: the ball is in contact with two small shafts that are set at right angles to each other. As the ball moves these shafts rotate, and the rotation is measured by sensors within the mouse. The distance and direction information from the sensors is then transmitted to the computer, and the computer moves the graphical pointer on the screen by following the movements of the mouse. Another common mouse is the optical mouse. This device is very similar to the conventional mouse but uses visible or infrared light instead of a roller-ball to detect the changes in position.


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, similar to an upside-down mouse: as the user rolls the ball with a thumb, fingers, or palm the mouse cursor on the screen will also move. Tracker balls are commonly used on CAD workstations for ease of use, where there may be no desk space on which to use a mouse. Some are able to clip onto the side of the keyboard and have buttons with the same functionality as mouse buttons. There are also wireless trackballs which offer a wider range of ergonomic positions to the user.

  • Isotonic joysticks are handle sticks where the user can freely change the position of the stick, with more or less constant force.
    • Joystick
    • Analog Stickbilatbao
  • Isometric joysticks – where the user controls the stick by varying the amount of force they push with, and the position of the stick remains more or less constant.
its also kind of hard for some people to use it.

 Pointing Stick
A pointing stick is a pressure sensitive small nub used like a joystick. It is usually found on laptops embedded between the 'G', 'H', and 'B' keys. It operatesbilatboto by sensing the force applied by the user. The corresponding "mouse" buttons are commonly placed just below the spacebar. It is also found on mice and some desktop keyboards.

A touchpad or trackpad is a flat surface that can detect finger contact. It's a stationary pointing device, commonly used on laptop computers At least one physical button normally comes with the touchpad, but the user can also generate a mouse click by tapping on the pad. Advanced features include pressure sensitivity and special gestures such as scrolling by moving one's finger along an edge.

Game controller
game controller is a device used with games or entertainment systems used to control a playable character or object, or otherwise provide input in a computer game. A controller is typically connected to a game console or computer by means of a wire, cord or nowadays, by means of wireless connection. Controllers which have been classified as game controllers are keyboards, mice, game pads, joysticks, etc. Special purpose devices, such as steering wheels for driving games and light guns for shooting games, are also game controllers. Devices such as mice and keyboards can be emulated with a game pad through the use of programs such as 'JoyToKey'.
The main function of a game controller is to govern the movement/actions of a playable body/object or otherwise influence the events in a video or computer game. The type of controller used in a game depends on the genre of the game being played (i.e. Steering Wheel controllers for driving games, yoke like for flying, etc.).

Digital Camera 
digital camera (or digicam) is a camera that takes video or still photographs or both, digitally by recording images via an electronic image sensor It is the main device used in the field of digital photography Most 21st century cameras are digital.

Front and back of Canon Powershot A95
Digital cameras can do things film cameras cannot: displaying images on a screen immediately after they are recorded, storing thousands of images on a single small memory device, and deleting images to free storage space. The majority, including most compact cameras, can record moving video with sound as well as still photographs. Some can crop and stitich pictures and perform other elementary image editing. Some have a GPS receiver built in, and can produce Geotagged phtographs

Voice Input Overview

voice input device A device in which speech is used to input data or system commands directly into a system. Such equipment involves the use of speech recognition processes, and can replace or supplement other input devices. 
People with disabilities have huge hopes for operating their computers simply by speaking, hopes that may not match the reality of current technology. 
Research has shown that having realistic expectations is the biggest predictor for success in using voice input technology for people with disabilities. 
As voice input systems become more numerous, and commercial advertising for these products becomes more pervasive, it becomes increasingly important for consumers and those assisting them to have clear information about this technology.

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