Principles of Information Systems - Chapter 13

Principles of Information Systems, Sixth Edition

Systems Design, Implementation, Maintenance, and Review

Chapter 13


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.



• 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.



• 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.


Systems Design


Top Uses for New Systems in Various Industries


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


Physical Design

• Hardware design• Software design• Database design• Telecommunications design• Personnel design• Procedures and controls design


Special System Design Considerations

• Procedures for signing on• Interactive processing • Interactive dialog• Preventing, detecting, and correcting errors


The Scope of Design


Procedures for Signing On


Interactive Processing


Emergency Alternate Procedures & Disaster Recovery

• Telecommunications backup• Personnel backup• Hardware backup• Software and database backup


Hardware Backup

• Disaster recovery plans• Hot site• Cold site


Software & Database Backup

• Selective backups• Incremental backups• Image log


Preventing, Detecting, and Correcting Errors


Object-Oriented Design


Systems Controls

• Deterrence controls• Input controls• Processing controls• Output controls• Database controls• Telecommunications controls• Personnel controls


Request for Proposal


Financial Options


Cost/Benefit Analysis


Cost/Benefit Analysis


Evaluation Techniques

• Group consensus• Benchmark tests• Cost/benefit analysis• Point evaluation


The Final Evaluation


Point Evaluation


Freezing Design Specifications


The Design Report


Systems Implementation


Systems Implementation


Acquiring Software: Make or Buy Software?

• Externally developed software– Lower cost – Lower risk– Ease of installation


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


In-House Developed Software

• Chief programmer teams • The programming life cycle


Chief Programmer Teams


The Programming Life Cycle


Tools & Techniques for Software Development

• Cross-platform development• Integrated development environments • CASE tools• Structured design• Structured programming• Structured walkthroughs


Characteristics of Structured Programming


Structured Design and Programming


Structured Design and Programming


Structured Walkthroughs


Additional Implementation Activities

• Acquiring database and telecommunication systems

• User preparation• Hiring and training IS personnel• Site preparation• Data preparation


Additional Implementation Activities

• Installation• Testing

– Unit testing– System testing– Volume testing– Integration testing– Acceptance testing


Testing


Start-Up Approaches


Start-Up Approaches


Systems Maintenance


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


Types of Maintenance

• Slipstream upgrade• Patch• Release• Version


The Financial Implications of Maintenance


The Relationship Between Maintenance and Design


Systems Review


Types of Review Procedures


Factors to Consider During Systems Review

• Mission• Goals• Hardware/software• Database• Telecommunications• IS personnel• Control

• Training• Costs• Complexity• Reliability• Efficiency• Response time• Documentation


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

Education

Principles of Information Systems - Chapter 13