Download chapter - FSU Computer Courses for Non

Chapter 8:
Systems
Development
Topics:
Please turn your
cell phone off.
Systems Investigation
Systems Analysis
Systems Design
Systems Implementation
Systems Maintenance and Review
Systems Development Life Cycle
Problem Solving
Intelligence Stage
Design Stage
Choice Stage
Implementation
Monitoring
2
Chapter 8.1
An Overview of Systems
Development
Key Terms
•
•
•
•
•
Stakeholders
Users
Systems analyst
Programmer
Information systems
planning
Participants in Systems
Development
 Effective systems
development
requires a team
effort.
www.monster.com
4
Participants
 Stakeholders
 People who benefit from the systems development
project
 Users
 People who will interact with the system regularly
 Systems analyst
 Person who specializes in analyzing and designing
business systems
 Programmer
 Person responsible for modifying or developing
programs to satisfy user requirements
5
Information Systems Planning
 The translation of
strategic and
organizational goals
into system
development
initiatives.
Designing new systems or
modifying existing ones should
always be aimed at helping an
organization achieve its goals.
6
Importance of IS Planning
Figure 8.3: The Steps of IS Planning
7
Chapter 8.2
Systems Development
Life Cycle
Key Terms
• Rapid application
Systems investigation
development (RAD)
Systems analysis
• Joint application
Systems design
Systems implementation development (JAD)
• End-user systems
Systems maintenance
development
and review
• Prototyping
•
•
•
•
•
• Computer-aided software
engineering (CASE)
• Object-oriented systems
development (OOSD)
The Traditional Systems
Development Life Cycle
Figure 8.4: The Traditional Systems Development Life Cycle
9
The Traditional Systems
Development Life Cycle
 Systems investigation: problems and
opportunities are identified and considered in
light of the goals of the business
 Systems analysis: study of existing systems
and work processes to identify strengths,
weaknesses, and opportunities for improvement
 Systems design: defines how the information
system will do what it must do to obtain the
problem’s solution
10
The Traditional Systems
Development Life Cycle
 Systems implementation: the creation or
acquiring of various system components
detailed in the systems design, assembling
them, and placing the new or modified system
into operation
 Systems maintenance and review: ensures
that the system operates, and modifies the
system so that it continues to meet changing
business needs
11
Prototyping
 Prototyping
Iterative
approach
to system design
12
RAD & JAD
 Rapid application development (RAD): a
systems development approach that employs
tools, techniques, and methodologies designed
to speed application development
 Joint application development (JAD): a
process for data collection and requirements
analysis in which users, stakeholders, and IS
professionals work together to analyze existing
systems, propose possible solutions, and define
the requirements for a new or modified system
13
The End-User Systems
Development Life Cycle
 Any systems development project in which the
primary effort is undertaken by a combination of
business managers and users
 End-user-developed systems can be structured
as complementary to, rather than in conflict with,
existing and emerging information systems
14
Use of Computer-Aided Software
Engineering (CASE) Tools
 Computer-aided software engineering
(CASE)

Tools that automate many of the tasks
required in a systems development effort and
enforce adherence to the SDLC
15
Use of Computer-Aided Software
Engineering (CASE) Tools
Table 8.2: Advantages and Disadvantages of CASE Tools
16
Object-Oriented Systems
Development
 OOSD
 The approach that combines the logic of the systems
development life cycle with the power of object-oriented
modeling and programming.
 Object-oriented systems development typically involves:
 Identifying potential problems and opportunities within the
organization that would be appropriate for the OO
approach
 Defining the kind of system users require
 Designing the system
17
Object-Oriented Systems
Development
 Object-oriented systems development typically
involves (continued):



Programming or modifying modules
Evaluation by users
Periodic review and modification
18
Chapter 8.3
Systems Investigation
Key Terms
•
•
•
•
•
•
Systems request form
Feasibility analysis
Technical feasibility
Economic feasibility
Legal feasibility
Operational feasibility
• Schedule feasibility
• Systems investigation report
Systems Investigation
 Identify potential problems and
opportunities and consider them in
light of the goals of the company.
 Formal procedures for initiating
systems development typically
include a Systems Request Form:




Identifies problems in or opportunities for
the system
States objectives of systems
investigation
Presents an overview of the proposed
system
Projects expected costs and benefits of
the proposed system
20
Feasibility Analysis
 Feasibility analysis is the assessment of the
technical, economic, legal, operational, and
schedule feasibility of a project
 Technical feasibility
 Economic feasibility
 Legal feasibility
 Operational feasibility
 Schedule feasibility
21
Feasibility Analysis
 Systems investigation report

A summary of the results of the systems
investigation and the process of feasibility
analysis and recommendations of a course of
action.
22
The Systems Investigation Report
Figure 8.8: A Typical Table of Contents for a Systems
Investigation Report
23
Chapter 8.4
Systems Analysis
Key Terms
•
•
•
•
•
•
Structured interview
Unstructured interview
Direct observation
Questionnaires
Data analysis
Data-flow diagram (DFD)
• Requirements analysis
• Asking directly
Systems Analysis
 Data Collection


Seeks additional information
about problems or needs.
Internal and External Sources
 Data Analysis


Data Modeling with entityrelationship diagrams
Activity Modeling with data-flow
diagrams
25
Data Collection
 Identifying sources of data


Internal sources
External sources
 Collecting data



Interviews
Direct observation
Questionnaires
26
Data Collection
Figure 8.9: Internal and External Sources of Data for
Systems Analysis
27
Collecting Data
 Structured interviews

Questions are written in advance
 Unstructured interviews

Questions are not written in advance
 Direct observation

Watching the existing system in action by one
or more members of the analysis team
28
Data Analysis
 Questionnaires

Gathering data when the data sources are spread
over a wide geographic area
 Data modeling

Entity-relationship (ER) diagrams
 Activity modeling

Data-flow diagrams (DFDs)

A model of objects, associations, and activities by
describing how data can flow between and around
various objects
29
Data Analysis
Figure 8.11: Data and Activity Modeling
(a) An entity-relationship diagram
30
Data Analysis
Figure 8.11: Data and Activity Modeling (continued)
(b) A data-flow diagram
31
Data Analysis
Figure 8.11: Data and Activity Modeling (continued)
(c) A semantic description of the business process
32
Requirements Analysis
 Requirements analysis

Determination of user, stakeholder, and
organizational needs
 Asking directly

An approach to gather data that asks users,
stakeholders, and other managers about what
they want and expect from the new or modified
system
33
Object-Oriented Systems Analysis
 Identifying problems or potential opportunities
 Identifying key participants and collecting data
 Instead of analyzing the existing system using
data-flow diagrams and flowcharts, an objectoriented approach is used
34
Object-Oriented Systems Analysis
Figure 8.13: Generalization/Specialization Hierarchy
Diagram for Single and Tandem Kayak Classes
35
Chapter 8.5
Systems Design
Key Terms
•
•
•
•
Logical design
Physical design
Request for proposal (RFP)
Design report
Systems Design
 Answers question “How will the
information system solve a
problem?”
 Logical Design

Description of the functional
requirements of a system
 Physical Design
 Specification of the
characteristics of the system
components necessary to put
the logical design into action
37
Systems Design Alternatives
Request for Proposal
(RFP)
A document that
specifies in detail required
resources such as
hardware and software
 Sent to outside vendors

38
The Design Report
 Design report: the result of
systems design

Contains system specifications
 System specifications include
technical description of:


System outputs, inputs, and user
interfaces
Hardware, software, databases,
telecommunications, personnel,
and procedure components and
the way these components are
related
39
The Design Report
40
Figure 8.17: A Typical Table of Contents for a Systems Design Report
Chapter 8.6
Systems Implementation
Key Terms
• Make-or-buy decision
• Site preparation
• Data preparation or data
conversion
• Installation
• Start-up
• Direct conversion
(AKA Plunge or direct cutover)
• Phase-in approach, or
piecemeal approach
• Pilot start-up
• Parallel start-up
• User acceptance document
Systems Implementation
42
Acquiring Software: Make or Buy?
 Externally developed software
 In-house developed software
 Blend of external and internal software
development
 Renting software
 Reusing software from other development efforts
43
Site Preparation
 Preparation of the location of a new system
 Making room for a computer in an office
 Special wiring and air conditioning
 Special flooring
 Additional power circuits
44
Data Preparation
 Also called data conversion
 Ensuring all files and databases are ready to be
used with new computer software and systems
45
Installation
 The process of physically placing the computer
equipment on the site and making it operational
 Normally the manufacturer is responsible for
installing computer equipment
 Someone from the organization (usually the IS
manager) should oversee the process
46
Start-Up
 The process of making the final tested
information system fully operational
 Direct conversion (also called plunge or
direct cutover)

The process of stopping the old system and
starting the new system on a given date
 Phase-in approach

Slowly replacing components of the old system
with those of the new one
47
Start-Up
 Pilot start-up

The process of running the new system for one
group of users rather then for all users
 Parallel start-up

The process of running both the old and new
systems for a period of time, comparing the new
system’s output with the old system’s, reconciling
any differences, and finally eliminating the old
system
48
Start-up
49
User Acceptance
 User-acceptance document: formal agreement
signed by the user that states that a phase of the
installation or the complete system is approved
50
Chapter 8.7
Systems Operation &
Maintenance
Key Terms
• Systems operation
Systems Operation and
Maintenance
 Systems operation: use of a new or modified
system
 Systems maintenance: checking, changing,
and enhancing the system to make it more
useful in achieving user and organizational goals
52
Systems Maintenance
 Reasons for the need of
Maintenance:







Bugs or errors in the program
New requests from users and
stakeholders
Technical and hardware problems
Change in operating system or
hardware
Changes in business processes
Corporate mergers and acquisitions
Government regulations (HIPAA)
53
Chapter 8.8
Systems Review
Key Terms
• Event-driven review
• Time-driven review
Systems Review
 Process of analyzing systems to make sure that
they are operating as intended
 Often compares the performance and benefits of
the system as it was designed with the actual
performance and benefits of the system in
operation
 Event-driven review: review triggered by a
problem or opportunity, such as an error, a
corporate merger, or a new market for products
 Time-driven review: review performed after a
specified amount of time
55
Questions?
?
?
?