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246 PART THREE CONVENTIONAL METHODS FOR SOFTWARE ENGINEERING

QUICK What is the work product? An How do I ensure that I’ve done it right? Perform
LOOK effective representation of the sys- requirements engineering steps, including require-
tem must be produced as a con- ments elicitation, that lead to a solid specification.
sequence of system engineering. This can be a Then review all system engineering work prod-
prototype, a specification or even a symbolic ucts for clarity, completeness, and consistency. As
model, but it must communicate the operational, important, expect changes to the system require-
functional, and behavioral characteristics of the ments and manage them using solid SCM (Chap-
system to be built and provide insight into the sys- ter 9) methods.
tem architecture.

1
is, both business process engineering and product engineering work to allocate a
role for computer software and, at the same time, to establish the links that tie soft-
ware to other elements of a computer-based system.
In this chapter, we focus on the management issues and the process-specific activ-
ities that enable a software organization to ensure that it does the right things at the
right time in the right way.

10.1 COMPUTER-BASED SYSTEMS

The word system is possibly the most overused and abused term in the technical lex-
icon. We speak of political systems and educational systems, of avionics systems and
manufacturing systems, of banking systems and subway systems. The word tells us
little. We use the adjective describing system to understand the context in which the
word is used. Webster's Dictionary defines system in the following way:
1. a set or arrangement of things so related as to form a unity or organic whole; 2. a set of
facts, principles, rules, etc., classified and arranged in an orderly form so as to show a log-
ical plan linking the various parts; 3. a method or plan of classification or arrangement; 4.
an established way of doing something; method; procedure . . .
Five additional definitions are provided in the dictionary, yet no precise synonym is
suggested. System is a special word.
Borrowing from Webster's definition, we define a computer-based system as

A set or arrangement of elements that are organized to accomplish some predefined goal
by processing information.

The goal may be to support some business function or to develop a product that can
be sold to generate business revenue. To accomplish the goal, a computer-based sys-
tem makes use of a variety of system elements:

1 In reality, the term system engineering is often used in this context. However, in this book, the
term system engineering is generic and is used to encompass both business process engineering
and product engineering.