EXERCISE 2.1
Individually or in a group find as many
different examples as you can of physical controls
and displays.
(a) List them
(b) Try to group them, or classify them.
(c) Discuss whether you believe the control or display
is suitable for its purpose. (section 3.9.3 may also
help)
answer
open-ended investigation
EXERCISE 2.2
Exercises 2.2 and 2.3 involve you examining
a range of input and output devices in order to understand
how they influence interaction.
A typical computer system is comprised
of a QWERTY keyboard, a mouse, and a colour screen.
There is usually some form of loudspeaker as well.
You should know how the keyboard, mouse and screen
work - if not, read up on it.
What sort of input does the keyboard
support? What sort of input does the mouse support?
Are these adequate for all possible applications?
If not, to which areas are they most suited? Do these
areas map well onto the typical requirements for users
of computer systems?
If you were designing a keyboard for
a modern computer, and you wanted to produce a faster,
easier to use layout, what information would you need
to know and how would that influence the design?
answer available for tutors only
EXERCISE 2.3
Pick a couple of computer input devices
that you are aware of (joystick, light pen, touchscreen,
trackball, eyegaze, dataglove, etc.) and note down
how each has different attributes that support certain
forms of interaction. You ought to know a little about
all of these devices - if you do not, research
them.
answer
open-ended investigation
EXERCISE 2.4
What is the myth of the infinitely fast
machine?
answer available for tutors only
EXERCISE 2.5
Pick one of the following scenarios,
and choose a suitable combination of input and output
devices to best support the intended interaction.
It may help to identify typical users or classes of
user, and identify how the devices chosen support
these people in their tasks. Explain the major problems
that the input and output devices solve.
Environmental database
A computer database is under development
that will hold environmental information. This ranges
from meteorological measurements through fish catches
to descriptions of pollution, and will include topographical
details and sketches and photographs. The data has
to be accessed only by experts, but they want to be
able to describe and retrieve any piece of data within
a few seconds.
Word processor for blind people
A word processor for blind users is needed,
which can also be operated by sighted people. It has
to support the standard set of word-processing tasks.
answer available for tutors only
EXERCISE 2.6
Describe Fitts' Law (see chapter 1).
How does Fitts' Law change for different physical
selection devices, such as a 3-button mouse, a touchpad,
or a pen/stylus? (You'll need to do some research
for this.)
answer available for tutors only
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