•
•The traditional
computer input interface is inefficient for the following reasons (Westerman, Elias, and Hedge, 2001) :
•
–Must switch a
hand between typing and pointing activities
–Separate
devices require different skill sets:
typing movements for keyboards,
mostly point-and-click operations for other input
devices.
–Most input
devices can only be operated with one hand.
–The physical
arrangement can be a risk factor in the development of musculoskeletal disorders
–Physical area
required for a keyboard and a mouse or other input device is an inefficient use of workspace.