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Principles of Information Systems, Seventh Edition 2
• 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
• Describe some considerations in design modeling and the diagrams used during object-oriented design
• Outline key considerations in interface design and control and system security and control.
• 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
Principles of Information Systems, Seventh Edition 3
• 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
Principles of Information Systems, Seventh Edition 4
• 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
Principles of Information Systems, Seventh Edition 5
Systems Design
• Answers the question “How will the information system do what it must do to solve a problem?”
• Has two dimensions: logical and physical
• 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
Principles of Information Systems, Seventh Edition 6
Logical Design
• Output requirements
• Input requirements
• Process requirements
• File and database requirements
Principles of Information Systems, Seventh Edition 7
Logical Design (continued)
• Telecommunications requirements
• Procedure requirements
• Controls and security requirements
• Personnel and job requirements
Principles of Information Systems, Seventh Edition 8
Physical Design
• Hardware specifications
• Software specifications
• Database specifications
Principles of Information Systems, Seventh Edition 9
Physical Design (continued)
• Telecommunications specifications
• Personnel specifications
• Procedure and control specifications
Principles of Information Systems, Seventh Edition 10
Object-Oriented Design
• Design key objects and classes of objects in the new or updated system
• Consideration of the problem domain, the operating environment, and the user interface
• Consideration of the sequence of events that must happen for the system to function correctly
• A sequence of events is often called a scenario
• A scenario can be diagrammed in a sequence diagram
Principles of Information Systems, Seventh Edition 11
Figure 13.4: The Levels of the Sign-On Procedure
Principles of Information Systems, Seventh Edition 12
Interface Design and Controls (continued)
• Interactive processing
• Menu-driven systems
• Help commands
• Table lookup facilities
• Restart procedures
Principles of Information Systems, Seventh Edition 13
Table 13.1: The Elements of Good Interactive Dialogue
Principles of Information Systems, Seventh Edition 14
Design of System Security and Controls
• Preventing, detecting, and correcting errors
• Disaster planning and recovery
• Disaster planning: the process of anticipating and providing for disasters
• Disaster recovery: the implementation of the disaster plan
• Hardware backup
Principles of Information Systems, Seventh Edition 15
Design of System Security and Controls (continued)
• Disaster planning and recovery (continued)
• Software and database backup
• Telecommunications backup
• Personnel backup
• Systems controls: rules and procedures to maintain data security
Principles of Information Systems, Seventh Edition 16
Generating Systems Design Alternatives
• Request for proposal (RFP): a document that specifies in detail required resources such as hardware and software
• Financial options
Principles of Information Systems, Seventh Edition 17
Evaluating and Selecting a Systems Design
• Preliminary evaluation
• To dismiss the unwanted proposals
• Begins after all proposals have been submitted
• Final evaluation
• A detailed investigation of the proposals offered by the vendors remaining after the preliminary evaluation
Principles of Information Systems, Seventh Edition 18
Figure 13.7: The Stages in Preliminary and Final Evaluations
Principles of Information Systems, Seventh Edition 19
Evaluation Techniques
• Group consensus
• Cost/benefit analysis
• Benchmark tests
• Point evaluation
Principles of Information Systems, Seventh Edition 20
Figure 13.8: An Illustration of the Point Evaluation System
Principles of Information Systems, Seventh Edition 21
Figure 13.9: Freezing Design Specifications
Principles of Information Systems, Seventh Edition 22
The Design Report
• Primary result of systems design
• Reflects the decisions made and prepares the way for systems implementation
Principles of Information Systems, Seventh Edition 23
Figure 13.11: Typical Steps in Systems Implementation
Principles of Information Systems, Seventh Edition 24
Acquiring Hardware from an IS Vendor
• An IS vendor is a company that offers hardware, software, telecommunications systems, databases, IS personnel, and/or other computer-related resources
• Buying computer hardware
• Leasing computer hardware
• Renting computer hardware
• “Pay-as-you-go,” “on-demand,” or “utility” computing
Principles of Information Systems, Seventh Edition 25
Acquiring Software: Make or Buy?
• Externally developed software: lower cost, lower risk, ease of installation
• In-house developed software
• Meeting user and organizational requirements
• More features and increased flexibility in terms of customization and changes
Principles of Information Systems, Seventh Edition 26
Acquiring Software: Make or Buy? (continued)
• In-house developed software (continued)
• Greater potential for providing a competitive advantage
• Chief programmer teams
• The programming life cycle
• Tools and techniques for software development
Principles of Information Systems, Seventh Edition 27
Figure 13.13: Steps in the Programming Life Cycle
Principles of Information Systems, Seventh Edition 28
Tools and Techniques for Software Development
• Structured programming
• Improving the logical program flow by breaking the program into groups of statements, called structures
• CASE tools: used during software development to automate some of the techniques
• Object-oriented implementation
• A collection of existing modules of code, or objects, can be used across a number of applications
Principles of Information Systems, Seventh Edition 29
Tools and Techniques for Software Development (continued)
• Cross-platform development: allows programmers to develop programs that can run on computer systems having different hardware and operating systems, or platforms
• Integrated development environment: combines the tools needed for programming with a programming language into one integrated package
• Structured walkthrough: a planned and preannounced review of the progress of a program module, a structure chart, or a human procedure
Principles of Information Systems, Seventh Edition 30
Acquiring Database and Telecommunications Systems
• Relational databases
• Object-oriented database systems
• Databases are a blend of hardware and software
• Telecommunications systems require a blend of hardware and software
Principles of Information Systems, Seventh Edition 31
User Preparation
• Readying managers, decision makers, employees, other users, and stakeholders for new systems
• Training users
Principles of Information Systems, Seventh Edition 32
IS Personnel: Hiring and Training
• IS manager
• Systems analysts
• Computer programmers
• Data-entry operators
Principles of Information Systems, Seventh Edition 33
Site Preparation
• Preparation of the location of a new system
• Making room for a computer in an office
• Special wiring and air conditioning
• Special floor
• Additional power circuits
Principles of Information Systems, Seventh Edition 34
Data Preparation
• Also called data conversion
• Ensuring all files and databases are ready to be used with new computer software and systems
Principles of Information Systems, Seventh Edition 35
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
Principles of Information Systems, Seventh Edition 36
Testing
• Unit testing: testing of individual programs
• System testing: testing the entire system of programs
• Volume testing: testing the application with a large amount of data
• Integration testing: testing all related systems together
• Acceptance testing: conducting any tests required by the user
Principles of Information Systems, Seventh Edition 37
Start-Up
• The process of making the final tested information system fully operational
• Direct conversion (also called plunge or direct cutover)
• Phase-in approach
• Pilot start-up
• Parallel start-up
Principles of Information Systems, Seventh Edition 38
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
Principles of Information Systems, Seventh Edition 39
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
Principles of Information Systems, Seventh Edition 40
Types of Maintenance
• Slipstream upgrade
• Patch
• Release
• Version
Principles of Information Systems, Seventh Edition 41
Figure 13.19: Maintenance Costs as a Function of Age
Principles of Information Systems, Seventh Edition 42
Figure 13.20: The Value of Investment in Design
Principles of Information Systems, Seventh Edition 43
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
Principles of Information Systems, Seventh Edition 44
Factors to Consider During Systems Review
• Mission
• Organizational goals
• Hardware and software
• Database
• Telecommunications
Principles of Information Systems, Seventh Edition 45
Factors to Consider During Systems Review (continued)
• Information systems personnel
• Control
• Training
• Costs
• Complexity
Principles of Information Systems, Seventh Edition 46
Factors to Consider During Systems Review (continued)
• Reliability
• Efficiency
• Response time
• Documentation
Principles of Information Systems, Seventh Edition 47
Summary
• Systems design answers the question “How will the information system do what it must do to solve a problem?”
• Systems design has two dimensions: logical and physical
• Logical design is description of the functional requirements of a system
• Physical design is specification of the characteristics of the system components necessary to put the logical design into action
Principles of Information Systems, Seventh Edition 48
Summary (continued)
• Steps of systems implementation: hardware acquisition, software acquisition, user preparation, personnel: hiring and training, site preparation, data preparation, installation, testing, start-up, and user acceptance
• Systems operation is the use of a new or modified system
• Systems maintenance involves checking, changing, and enhancing the system to make it more useful in achieving user and organizational goals
Principles of Information Systems, Seventh Edition 49
Summary (continued)
• Systems review is the process of analyzing systems to make sure that they are operating as intended
• Event-driven review is triggered by a problem or opportunity such as an error, a corporate merger, or a new market for products
• Time-driven review is performed after a specified amount of time