Examples of "Enabling Technology"
The examples below illustrate the difference between user-interfaces
that are or are not usable, but that are all able to execute each step
of a task:
- The steering wheel:
The steering wheel is able to make the car turn (within certain limits).
However, in order to use it without crashing into things one needs
visual feedback about where you are heading (which is why blind people
cannot drive although they can control all the handles).
A steering wheel as input device is not usable without visual feedback.
- Joystick in Airplane:
In some modern airplanes the traditional "steering wheel(s)" have been
replaced by joysticks. After initial training, pilots can fly the plane
just as easily using the joystick. However, there have been near-accidents
because the pilot's and co-pilot's joysticks are not coupled, so neither
gets feedback about the actions of the other. (The steering wheels were
always coupled, providing tactile feedback.)
A joystick in modern airplanes proved difficult to use because the pilot's
and co-pilot's joysticks were not coupled.
- "Windows" key:
The addition of the "Windows" key in Windows'95 gives (knowledgeable)
users quick access to the startup menu and some popular
applications (such as the Windows Explorer).
Unfortunately many applications that wish to take complete control of
the keyboard seem unable to disable the Windows key.
This causes the startup menu to appear in children's (toddlers') games.
The "Windows" key in Windows'95 provides extra keyboard shortcuts for
(knowledgeable) users, but disturbs applications that wish to take
control of the keyboard.
Back to introduction on UI-design.