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Systems Design, Implementation, Maintenance, and Review
Chapter 13
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Principles and Learning Objectives
• Designing new systems or modifying existing ones should always be aimed at helping an organization achieve its goals.
– State the purpose of systems design and discuss the differences between logical and physical systems design.
– Outline key steps taken during the design phase.– Describe some considerations and diagrams used during
object-oriented design.– Define the term RFP and discuss how this document is used
to drive the acquisition of hardware and software.– Describe the techniques used to make systems selection
evaluations.
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Principles and Learning Objectives
• The primary emphasis of systems implementation is to make sure that the right information is delivered to the right person in the right format at the right time.
– State the purpose of systems implementation and discuss the various activities associated with this phase of systems development.
– List the advantages and disadvantages of purchasing versus developing software.
– Discuss the software development process and some of the tools used in this process, including object-oriented program development tools.
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Principles and Learning Objectives
• Maintenance and review add to the useful life of a system but can consume large amounts of resources. These activities can benefit from the same rigorous methods and project management techniques applied to systems development.
– State the importance of systems and software maintenance and discuss the activities involved.
– Describe the systems review process.
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Systems Design
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Top Uses for New Systems in Various Industries
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Logical Design
• Output design: types, format, content, frequency• Input design: types, format, content, frequency• Process design: calculations, comparisons,
manipulations• File & database design: capabilities and organization• Telecommunications design: high-level network
description• Procedures design: automated & manual• Controls & security design• Personnel & job design
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Physical Design
• Hardware design• Software design• Database design• Telecommunications design• Personnel design• Procedures and controls design
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Special System Design Considerations
• Procedures for signing on• Interactive processing • Interactive dialog• Preventing, detecting, and correcting errors
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The Scope of Design
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Procedures for Signing On
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Interactive Processing
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Emergency Alternate Procedures & Disaster Recovery
• Telecommunications backup• Personnel backup• Hardware backup• Software and database backup
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Hardware Backup
• Disaster recovery plans• Hot site• Cold site
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Software & Database Backup
• Selective backups• Incremental backups• Image log
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Preventing, Detecting, and Correcting Errors
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Object-Oriented Design
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Systems Controls
• Deterrence controls• Input controls• Processing controls• Output controls• Database controls• Telecommunications controls• Personnel controls
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Request for Proposal
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Financial Options
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Cost/Benefit Analysis
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Cost/Benefit Analysis
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Evaluation Techniques
• Group consensus• Benchmark tests• Cost/benefit analysis• Point evaluation
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The Final Evaluation
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Point Evaluation
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Freezing Design Specifications
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The Design Report
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Systems Implementation
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Systems Implementation
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Acquiring Software: Make or Buy Software?
• Externally developed software– Lower cost – Lower risk– Ease of installation
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Make or Buy Software
• Steps– Review needs, requirements, and costs– Acquire software– Modify or customize software– Acquire software interfaces– Test and accept the software– Maintain the software
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In-House Developed Software
• Chief programmer teams • The programming life cycle
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Chief Programmer Teams
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The Programming Life Cycle
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Tools & Techniques for Software Development
• Cross-platform development• Integrated development environments • CASE tools• Structured design• Structured programming• Structured walkthroughs
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Characteristics of Structured Programming
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Structured Design and Programming
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Structured Design and Programming
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Structured Walkthroughs
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Additional Implementation Activities
• Acquiring database and telecommunication systems
• User preparation• Hiring and training IS personnel• Site preparation• Data preparation
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Additional Implementation Activities
• Installation• Testing
– Unit testing– System testing– Volume testing– Integration testing– Acceptance testing
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Testing
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Start-Up Approaches
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Start-Up Approaches
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Systems Maintenance
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Reasons for Maintenance
• Changes in business processes• Requests from stakeholders, users, or managers• Errors in the program• Technical and hardware problems• Corporate mergers & acquisitions• Government regulations• Changes in the operating system or hardware
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Types of Maintenance
• Slipstream upgrade• Patch• Release• Version
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The Financial Implications of Maintenance
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The Relationship Between Maintenance and Design
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Systems Review
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Types of Review Procedures
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Factors to Consider During Systems Review
• Mission• Goals• Hardware/software• Database• Telecommunications• IS personnel• Control
• Training• Costs• Complexity• Reliability• Efficiency• Response time• Documentation
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Summary
• Systems design - preparing detailed design needs for a new system or modifying an existing system
• Systems implementation – installing the system and making everything, including users, ready for its operation
• Software - can be purchased from vendors or developed in-house - a decision termed the make-or-buy
• Systems maintenance - involves checking, changing, and enhancing the system to make it more useful in obtaining user and organizational goals
• Systems review - the process of analyzing systems to make sure that they are operating as intended