Systems Design, Implementation, Maintenance, and Review

MSIS 110: Introduction to Computers; Instructor: S. Mathiyalakan 1

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

Systems Design, Implementation, Maintenance, and Review

Documents

computers instructor

purpose of systems design

physical systems design

objectoriented design

design phase

frequencyprocess design

frequencyinput design

importance of systems