Chapter 8 Basic Systems Concepts and Tools
Chapter 8
Basic Systems Concepts and Tools
Objectives and Overview
The primary objective of this chapter is to provide an introduction to systems concepts in general,
as well as some specific methods and techniques for developing and maintaining information
systems. In selecting this material we have focused on concepts important to both IS specialists
Undergraduate business students who are not IS majors may wonder how they can use the general
systems concepts material in this chapter in the future. These students may have used approaches
Several themes dominate this chapter. First, the chapter introduces a systems view of an
organization and some systems terminology (e.g., inputs, outputs, components). The systems
The chapter objectives can be summarized as follows:
To understand the systems view of organizations and the applicability of this perspective to
Chapter 8 Basic Systems Concepts and Tools
Teaching Suggestions
This chapter can be used as background reading or as a primary reading for in-class discussion.
For students with no prior systems analysis and design coursework, you might choose to devote
one 50 to 75 minute lecture to discussing and illustrating the concepts introduced in the chapter
and then concentrate your discussion on selected figures provided with the chapter.
Alternatively, you may wish to only select a few major concepts from this chapter and to
introduce them with other chapters and cases. For example, the DFD and ER techniques can be
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develop a top-level data flow diagram for a logical As-Is model of a system that all students are
familiar with such as renting a video for the first time or registering for university courses. A
The following are some additional activities that relate to the chapter material:
1.
2. The Leavitt diamond in Figure 8.5 sets up the concept of organizations as systems in which a
change in one major component requires compensating changes in other components. Your
3. Use Figure 8.7 (How IT Enables New Ways to Work) to engage your students in a discussion
of processes (at the university or their place of work) that could be improved by using IT.
4. You might want to invite an IT systems (EDP) auditor to be a guest lecturer in class. This
guest auditor could review the types of controls for information systems that are typically
5. You might want to invite to be a guest lecturer a manager of IS development in an
6. Depending on the background of your students, you might want them to compare systems
Review Questions
1. Define the term system. Give an example of a business system and use a context diagram
to show its boundary, environment, inputs, and outputs.
A system is a set of interrelated components that must work together to achieve some common
purpose. The interconnectedness and mutual dependencies inherent to system components are
2. Define the term subsystem. Give an example of a business subsystem and identify some
subsystems with which it relates.
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3. What are the seven key elements of a system, and what role does each element play in
describing a system?
The seven elements are as follows:
Boundary delineates what is inside and outside the system; it is assumed that elements
within the boundary are more easily changed and controlled than those outside.
Environment everything outside the system; the environment provides assumptions,
constraints, and inputs to the system (and receives output from the system).
4. What happens at the point where two systems interact?
5. Explain the first two principles of systems analysis and design.
The first two principles are:
Choose an appropriate scope this means selecting the system boundary, which will
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6. Define the term business process reengineering and describe its importance for IS work.
BPR refers to business initiatives to redesign business processes by questioning assumptions and
rules underlying the status quo. The overall objective of BPR is to increase the efficiency and
7. Describe how logical and physical representations of a To-Be system will differ.
The logical To-Be representation identifies the processes and data flows of a desired system, and
8. Describe the relationships between a context diagram, as in Figure 8.11, and the top-level
and second-level diagrams of a data flow diagram, as in Figure 8.13.
A context diagram defines the system boundary and its major inputs and outputs; it therefore
9. What is a data dictionary and why is it important?
10.
Chapter 8 Basic Systems Concepts and Tools
11. What are analysis and design patterns and why are they useful for information systems
development?
Analysis and design patterns are abstractions and generalizations that address all aspects of a
12. Compare a context diagram (using DFD modeling) and a use case diagram (using
UML); what is the same and what is different?
13. What are the differences between a data entity in structured techniques and an object in
object-oriented techniques?
14. Briefly describe some common information system controls that need to be implemented
by business managers, not IS professionals.
Determining the frequency and extent of IS auditing is a key role played by business managers,
not IS professionals. In addition, many other IS controls should also by implemented with
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15. What is an audit trail and why is it a useful mechanism for controlling business risks
due to an information system?
16. In what way does thorough documentation for an information system help in
compliance with regulations such as Sarbanes-Oxley?
17. What is the Information Technology Infrastructure Library and what benefits does it
provide for implementation of information systems?
A rather extensive set of international guidelines have been developed called the Information
Discussion Questions
1. Explain and give an example that supports the following statement: Each time we change
characteristics of one or more of the components of the organization (organization
structure, people, business processes, and information technology), we must consider
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compensating changes in the other components.
As shown in Figure 9.5, a change in one component commonly requires changes in other
components. For example, suppose that a data warehouse is implemented and sales managers are
2. Explain the function of hierarchical decomposition in systems analysis and design and
discuss the reasons for viewing and analyzing systems in this way.
Hierarchical decomposition is the process of breaking a system down into successive levels of
3. Why do informal systems arise? Why should systems analysts be aware of them?
4. Some observers have characterized business process reengineering (BPR) as
evolutionary, others as revolutionary. Develop an argument to support one of these sides.
5. Explain why many companies were unable to implement new cross-functional processes
that were identified by BPR project teams in the early 1990s, before ERP packages became
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widely available.
One common reason is that these organizations typically had separate systems for their business
functions that did not share a common database and that relied on custom software programs to
6. Describe why analysts begin with the As-Is system, rather than starting with the design of
a To-Be system.
Analyzing the As-Is system provides a starting point. It is usually easy to gain the cooperation of
7. Develop a context diagram and a top-level DFD to model the data flows involved in
8.11 and 8.13 are the textbook models provided for these types of diagrams.]
8. Discuss the differences between data stores on a DFD and an entity-relationship diagram
for the same information system application. What purpose does each serve? What does
each explain or show that the other does not?
A data store shows data at rest as part of a description of a process which stores and uses data; an
entity-relationship diagram (ERD) shows the structure of data independent of how or where the
9. Identify the construction controls for the class registration system of the previous
question. Justify why these controls would be adequate for data quality, security, and
recoverability.
The chapter identified the following types of Definition and Construction phase controls:
methodology standards, validation rules and calculations, and system testing. Other
10. Web services have been called a second wave of net-centric computing that will have
broad implications for software development approaches in the future. Develop an
argument to support or refute this viewpoint.
Possible supporting argument: Like software objects, Web services provide the means to allow
other programs to use data and processing logic without understanding the mechanics behind how
11. Explain why some organizations have adopted more rigid control mechanisms in recent
years and whether or not you think they are justified, given the added costs to implement
them.
More rigid control mechanisms have been put in place in recent years for two different types of
reasons: 1) increased scrutiny of the information provided by publicly traded companies, and 2)
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