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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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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• 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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Systems Controls
• Deterrence controls
• Input controls
• Processing controls
• Output controls
• Database controls
• Telecommunications controls
• Personnel controls
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Financial Options
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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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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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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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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
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