Information Technology Reference
In-Depth Information
Prototypes: Users typically have only an imprecise notion of
what they want, and because users' needs evolve and change, soft
ware developers may utilize a variety of techniques to refine pro
grams as they are being created and maintained. One such approach
is the use of
prototypes
—mockups of possible user interfaces, re
ports, and capabilities. A prototype presents a sample user window,
output, or feature that can be reviewed by users. The prototype may
not perform all desired tasks—for example, it may contain only
places for users to input data or sample output formats. Data en
tered may not actually be processed, outputs may contain sample
data only, and any processing may be slow or simplified. Even with
such limitations, however, a user can experience a design to deter
mine what seems helpful, what adjustments might be appropriate,
and what new or different features should be considered.
For example, in a prototype of a wordprocessing package,
the user might view a window that displays a box indicating the
current type font and another box for the size of the font. Buttons
might specify bold or italics or underlining. Such a window al
lows the potential user to comment on the layout of the word
processing screen, the way various features might be used, and the
range of current features. Multiple prototypes might provide al
ternative layouts so users could comment on the relative merits of
different layouts. However, in a prototype, the software might
support only one type font, without the actual option for bold,
italics, or underlining. One prototype for a wordprocessing pack
age might place boxes and buttons on the top, while another
might place a different collection of boxes and icons on the side,
and a third might split these elements along the top and bottom.
A prototype normally does not have full functionality; rather, it
provides insight regarding what would be most useful to include in
the real application. Sometimes, several prototypes for an applica
tion might be developed to ascertain what alternatives have greatest
appeal or usefulness. Thus, prototypes can help guide the design
process. Because prototypes have limited functionality, they may be
produced quickly and cheaply, allowing several alternatives to be
tested before committing much time and effort on a final system.
Extreme versus Classical Programming: In classical program de
velopment, the steps of specification, algorithm development, cod
ing, and testing follow in sequence—with the expectation that each
stage largely will be finalized before going to the next step. Thus,
considerable time is spent initially in performing market analysis,
