McLeod_CH07.ppt 4494KB Jan 27 2009 08:42:48 AM

Management
Information Systems,
Raymond McLeod
10/eand George
Schell

© 2007 by Prentice Hall

Management Information Systems, 10/e R
aymond McLeod and George Schell

1

Chapter 7
Systems Development

© 2007 by Prentice Hall

Management Information Systems, 10/e R
aymond McLeod and George Schell

2

Learning Objectives
► Recognize

the systems approach as the
basic framework for solving problems of
all kinds.
► Know how to apply the systems
approach to solving systems problems.
► Understand that the systems
development life cycle (SDLC) is a
methodology – a recommended way to
develop systems.
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Learning Objectives (Cont’d)
► Be

familiar with the main SDLC approaches –
the traditional waterfall cycle, prototyping,
rapid application development, phased
development, and business process redesign.
► Know the basics of modeling processes with
data flow diagrams and use cases.
► Understand how systems development
projects are managed in a top-down fashion.
► Be familiar with the basic processes of
estimating project cost.
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The Systems Approach
► John

Dewey identified three series of
judgments involved in adequately resolving a
controversy
1.Recognize the controversy
2.Weigh alternative claims
3.Form a judgment
► During the late 1960s/early 1970s, interest in
systematic problem solving strengthened
► Systems approach—a series of problemsolving steps that ensure the problem is first
understood, alternative solutions are
considered, and the selected solution works.
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Series of Steps
► Preparation

effort prepares the problem
solver by providing a systems orientation.
 Business areas, level of management, resource flows

► Definition

effort consists of identifying the
problem to be solved & then understanding it.
► Solution effort involves identifying alternative
solutions, evaluating them, selecting the one
that appears best, implementing that solution,
& following up to ensure that the problem is

solved.
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ystems, 10/e Raymond Mc

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Figure 7.1 Phases & Steps of
Systems Approach

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ystems, 10/e Raymond Mc

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Figure 7.2 Each Business Area is
a System

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Definition Effort Terminology
► Problem

trigger is a signal that things
are going better or worse than planned.
► Symptom is a condition that is produced
by the problem & is usually more obivious
than the root cause of the problem.
► Problem is a condition or event that is

harmful or potentially or beneficial or
potentially beneficial to the firm.
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Figure 7.3 Analyze System Parts
in Sequence

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Select the Best Solution
► Analysis

– a systematic evaluation of

options.
► Judgment – the mental process of a
single manager.
► Bargaining – negotiations between
several managers.

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Systems Development
Lifecycle
► Methodology

is a recommended way of
doing something.
► Systems development lifecycle (SDLC)
is an application of the systems approach to
the development of an information system.
► Traditional SDLC stages are:






Planning
Analysis
Design
Implementation

Use.

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Figure 7.4 Circular Pattern of the
System Life Cycle

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Prototyping
► Prototype

is a version of a potential
system that provides the developers &
future users with an idea of how the
system in its completed form will
function.
► Prototyping is the process of producing
a prototype.
► Best suited for small systems – reflecting
the prototyping influence.
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Evolutionary Prototype
► Evolutionary

prototype is continually
refined until it contains all of the
functionality that users require of the new
system. The steps involved are:
 Identify user needs.
 Develop prototype.
► Integrated

application developer
► Prototyping toolkit

 Determine if the prototype is acceptable.
 Use the prototype.
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Figure 7.5 Development of
Evolutionary Prototype

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Requirements Prototype
► Requirements

prototype is developed as
a way to define the functional requirements
of the new system when users are unable to
articulate exactly what they want. Begin
with the Evolutionary Prototype steps, then
the next steps are:





Code the new system;
Test the new system;
Determine if the new system is acceptable;
Put the new system into production.

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Figure 7.6 Development of
Requirements Prototype

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Attraction of Prototyping
► Communications

between the developer &
user are improved.
► The developer can do a better job of
determining the users’ needs.
► The user plays a more active role in system
development.
► The developers & the user spend less time &
effort developing the system.
► Implementation is much easier because the
user knows what to expect.
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Potential Pitfalls of
Prototyping
► The

haste to deliver the prototype may
produce shortcuts in problem definition,
alternative evaluation, & documentation. The
shortcut produces a “quick & dirty” effort.
► The user may get overly excited about the
prototype, leading to unrealistic expectations
regarding the production system.
► Evolutionary prototypes may not be very
efficient.
► The computer-human interface provided by
certain prototyping tools may not reflect good
design techniques.
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Rapid Application
Development
►

►

►
►
►

Rapid Application Development (RAD), is a
term coined by James Martin. It refers to a
development life cycle intended to produce systems
quickly without sacrificing quality.
Information engineering is the name that Martin
gives to his overall approach to system
development, which treats it as a firm-wide activity.
Enterprise is used to describe the entire firm.
Essential to RAD is management, people,
methodologies, & tools.
Best suited for large systems.

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Figure 7.7 Rapid Application
Development

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Phased Development
► Phased

development is an approach for
developing information systems that
consists of six stages:







Preliminary investigation
Analysis
Design
Preliminary construction
System test
Installation.

► Best

suited for systems of all sizes.

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Figure 7.8 Stages of Phases
Development

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Module Phases
► System

is subdivided into major
modules such as:




Report writer;
Database;
Web interface.

► Number

of modules varies with the
system from 1 to a dozen or so.
► Stages are performed separately for
each module.
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ystems, 10/e Raymond Mc

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Figure 7.9 Module Phase of
Systems Development

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Business Process Redesign
► Reengineering

or Business process redesign
(BPR) is the process of reworking the systems.
 Systems include both those that process the firm’s data
& those that perform basic functions such as drilling for
oil.

► BPR

affects the firm’s IT operations in two ways:

 Aids in the redesign of old information systems ( legacy
systems);
 Applies to the redesign of information systems to
support major operations.
► Usually

initiated at strategic management level.

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Figure 7.10 Top-Down Initiation
of BPR Projects

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Strategic Initiation of BPR
► Reverse

engineering is the process of
analyzing an existing system to:

 identify its elements & their interrelationships;
 Create documentation at a higher level of
abstraction than currently exists.

► Functionality

is the job that it performs.
► Reengineering is the complete redesign of
a system with the objective of changing its
functionality.
► Forward engineering is given to the
process of following the SDLC in the normal
manner while engaging in BPR.
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BPR Components
► BPR

components can be applied
separately or in combination.
► Functional quality is a measure of
what the system does.
► Technical quality is a measure of
how well it does it.

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Figure 7.11 BPR Component
Selection

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Methodologies in Perspective
► Traditional

SDLC is an application of the
systems approach to the problem of system
development; contains all elements.
► Prototyping is an abbrev. form focusing on
the definition & satisfaction of user needs.
► RAD is an alternative approach to the
design & implementation phases of SDLC.
► Phased development uses traditional
SDLC & applies it in a modular fashion.
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System Development Tools
► Process

modeling was first done with
flowcharts.
 ISO standards
 Use of 20+ symbols

► Data

flow diagrams (DFD) is a graphic
representation of a system that uses four
symbol shapes to illustrate how data flows
through interconnected processes..
► DFDs are excellent for modeling processes at
a summary level.
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Data Flow Diagram Symbols
►

Terminator describes an environmental element,
such as a person, organization, or another system.
 Environmental elements exist outside the boundary of
the system.

►
►

►
►

Process is something than transforms input into
output.
Data flow consists of a group of logically related
data elements that travel from one point or process
to another; can diverge and converge.
Data storage is a repository of data.
Connector contains the number of the process that
provides the data flow.

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Figure 7.12 DFD of a Sales
Commission System

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Leveled Data Flow Diagrams
Leveled DFDs is used to describe the hierarchy of
diagrams, ranging from context to lowest-level n
diagram.
► Figure 0 diagram identifies the major processes of a
system.
►

 Use additional DFDs to achieve documentation at both a more
summarized & a more detailed level.
►

Context diagram is a diagram that documents the
system at a more summarized level.
 Positions the system in a environmental context.

►

Figure n diagram is a diagram that provides more
detail.
 n represents the # of processes on the next higher level.
 Documents a single process of a DFD in greater detail.

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Figure 7.13 Context Diagram of
a Sales Commission System

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Figure 7.14 Figure 4 Diagram of
a Sales Commission System

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Use Cases
► Use

case is a narrative description in an
outline form of the dialog that occurs
between a primary & secondary system.
► Continuous narrative format with each
action numbered sequentially.
► Ping-pong format consists of two
narratives & the numbering indicates how
the tasks alternate between the primary &
secondary systems.
► Alternative events are actions that are not
normally expected to occur; alphabetic
letters are appended to step numbers.
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Figure 7.15 A Use Case

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Figure 7.16 Use Case
Guidelines

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Project Management
► Steering

committee is a committee
with the purpose of providing ongoing
guidance, direction, & control of all
systems projects.
► MIS steering committee purpose is
directing the use of the firm’s computing
resources.




It establishes policies.
It provides fiscal control.
It resolves conflict.

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Figure 7.17 Managers of a
System Life Cycle Arranged in a
Hierarchy

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Project Leadership
► Project

team includes all of the
persons who participate in the
development of an information
system.
► Team leader (project leader)
provides direction throughout the life
of the project.

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Project Management
Mechanism
► Basis

for project management is the project

plan.
► Gantt chart is a horizontal bar chart that
includes a bar for each task to be performed;
bars arranged in time sequence.
► Network diagram (CPM diagram, PERT
chart) is a drawing that identifies activities &
links them with arrows to show the sequence in
which they are to be performed.
► Narrative reports are in the form of weekly
written reports by project leader, communicates
project information to MIS steering committee.
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Figure 7.18 A Gantt Chart

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Figure 7.19 A Network
Diagram

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Project Cost-Estimating
►

Cost-estimating inputs





►

Work breakdown structure (WBS)
Resource requirements, resource rates
Activity duration estimates
Historical information

Cost-estimating tools & techniques
 Bottom-up estimating
 Computerized estimating
 Mathematical models

►

Cost-estimating outputs
 Supporting details
 Cost-management plan

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Table 7.1 Components of CostEstimating Process

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Table 7.2 Example of Project
Cost

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