Chapter 8:Systems
Development
Systems InvestigationSystems AnalysisSystems DesignSystems ImplementationSystems Maintenance and Review
Topics:
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Systems Development Life Cycle
Intelligence Stage
Design Stage
Choice Stage
Implementation
Monitoring
Problem Solving
An Overview of Systems Development
Chapter 8.1
Key Terms
• Stakeholders• Users• Systems analyst• Programmer• Information systems
planning
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Participants in Systems Development Effective systems
development requires a team effort.
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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
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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.
Designing new systems or modifying existing ones should always be aimed at helping an organization achieve its goals.
Systems Development Life Cycle
Chapter 8.2
Key Terms
• Systems investigation• Systems analysis• Systems design• Systems implementation• Systems maintenance
and review• Prototyping
• Rapid applicationdevelopment (RAD)
• Joint applicationdevelopment (JAD)
• End-user systems development
• Computer-aided softwareengineering (CASE)
• Object-oriented systemsdevelopment (OOSD)
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The Traditional Systems Development Life Cycle
Figure 8.4: The Traditional Systems Development Life Cycle
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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
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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
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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
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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
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Computer-aided software engineering (CASE) Tools that automate many of the tasks
required in a systems development effort and enforce adherence to the SDLC
Use of Computer-Aided Software Engineering (CASE) Tools
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Use of Computer-Aided Software Engineering (CASE) Tools
Table 8.2: Advantages and Disadvantages of CASE Tools
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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
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Object-Oriented Systems Development
Object-oriented systems development typically involves (continued): Programming or modifying modules Evaluation by users Periodic review and modification
Systems Investigation
Chapter 8.3
Key Terms
• Systems request form• Feasibility analysis• Technical feasibility• Economic feasibility• Legal feasibility• Operational feasibility
• Schedule feasibility• Systems investigation report
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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
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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
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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.
Feasibility Analysis
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The Systems Investigation Report
Figure 8.8: A Typical Table of Contents for a Systems Investigation Report
Systems Analysis
Chapter 8.4
Key Terms
• Structured interview• Unstructured interview• Direct observation• Questionnaires• Data analysis• Data-flow diagram (DFD)
• Requirements analysis• Asking directly
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Systems Analysis
Data Collection Seeks additional information
about problems or needs. Internal and External Sources
Data Analysis Data Modeling with entity-
relationship diagrams Activity Modeling with data-flow
diagrams
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Data Collection
Identifying sources of data Internal sources External sources
Collecting data Interviews Direct observation Questionnaires
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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
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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
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Data Analysis
Figure 8.11: Data and Activity Modeling (continued)(c) A semantic description of the business process
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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
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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 object-oriented approach is used
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Object-Oriented Systems Analysis
Figure 8.13: Generalization/Specialization Hierarchy Diagram for Single and Tandem Kayak Classes
Systems Design
Chapter 8.5
Key Terms
• Logical design• Physical design• Request for proposal (RFP)• Design report
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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
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Request for Proposal (RFP)
A document that specifies in detail required resources such as hardware and software
Sent to outside vendors
Systems Design Alternatives
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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
Systems Implementation
Chapter 8.6
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, orpiecemeal approach
• Pilot start-up• Parallel start-up• User acceptance document
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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
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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
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Data Preparation
Also called data conversion Ensuring all files and databases are ready to be
used with new computer software and systems
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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
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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
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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
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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
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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
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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)
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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