Information Technology Reference
In-Depth Information
• user and analyst speak different languages
• ease of omitting ''obvious'' information
• conflicting views of different users
• requirements are often overly vague and untestable, e.g., ''user friendly'' and
''robust''
• problems of volatility
• requirements evolve over time
The remainder of this section will discuss these problem areas in further detail.
(Christel and Kang
1992
)
5.3 Identifying the Requirements
A system will often times consist of hundreds or thousands of requirement
statements. To properly manage such a large number of requirements, they have to
be numbered with some type of identification scheme. There are several tech-
niques, a few of which are listed as follows: (Maciaszek
2001
)
• Unique identifier—usually a sequence number is assigned
• Sequential number within document hierarchy—assigned with consideration to
the requirement's position within the requirements document.
• Sequential number within requirement's category—assigned a mnemonic name
that identifies the category of requirement.
5.3.1 Identifying the Functional Requirements
Functional requirements capture the intended behavior of the system. This behavior
may be expressed as services, tasks or functions that the system is required to
perform. In product development, it is useful to distinguish between the baseline
functionality necessary for any system to compete in that product domain and the
features that differentiate the system from competitors' products, and from variants
in your company's own product line/family. Features may be additional function-
ality or differ from the basic functionality along some quality attribute (such as
performance or memory utilization). One strategy for quickly penetrating a market,
is to produce the core or a stripped down, basic product, and adding features to
variants of the product to be released shortly thereafter. This release strategy is
obviously also beneficial in information systems development, staging core func-
tionality for early releases and adding important features over the course of several
subsequent releases. In many industries, companies produce product lines with
different cost/feature variations per product in the line. Many product families
include a number of product lines targeted at somewhat different markets or usage
situations. What makes these product lines part of a family are some common
