Chapter 8:Systems

Development

Systems InvestigationSystems AnalysisSystems DesignSystems ImplementationSystems Maintenance and Review

Topics:

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Systems Development Life Cycle

Intelligence Stage

Design Stage

Choice Stage

Implementation

Monitoring

Problem Solving

An Overview of Systems Development

Chapter 8.1

Key Terms

• Stakeholders• Users• Systems analyst• Programmer• Information systems

planning

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Participants in Systems Development Effective systems

development requires a team effort.

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Participants

Stakeholders People who benefit from the systems development

project Users

People who will interact with the system regularly Systems analyst

Person who specializes in analyzing and designing business systems

Programmer Person responsible for modifying or developing

programs to satisfy user requirements

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Information Systems Planning

The translation of strategic and organizational goals into system development initiatives.

Designing new systems or modifying existing ones should always be aimed at helping an organization achieve its goals.

Designing new systems or modifying existing ones should always be aimed at helping an organization achieve its goals.

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Importance of IS Planning

Figure 8.3: The Steps of IS Planning

Systems Development Life Cycle

Chapter 8.2

Key Terms

• Systems investigation• Systems analysis• Systems design• Systems implementation• Systems maintenance

and review• Prototyping

• Rapid applicationdevelopment (RAD)

• Joint applicationdevelopment (JAD)

• End-user systems development

• Computer-aided softwareengineering (CASE)

• Object-oriented systemsdevelopment (OOSD)

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The Traditional Systems Development Life Cycle

Figure 8.4: The Traditional Systems Development Life Cycle

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The Traditional Systems Development Life Cycle Systems investigation: problems and

opportunities are identified and considered in light of the goals of the business

Systems analysis: study of existing systems and work processes to identify strengths, weaknesses, and opportunities for improvement

Systems design: defines how the information system will do what it must do to obtain the problem’s solution

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The Traditional Systems Development Life Cycle Systems implementation: the creation or

acquiring of various system components detailed in the systems design, assembling them, and placing the new or modified system into operation

Systems maintenance and review: ensures that the system operates, and modifies the system so that it continues to meet changing business needs

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Prototyping

PrototypingIterative approach

to system design

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RAD & JAD

Rapid application development (RAD): a systems development approach that employs tools, techniques, and methodologies designed to speed application development

Joint application development (JAD): a process for data collection and requirements analysis in which users, stakeholders, and IS professionals work together to analyze existing systems, propose possible solutions, and define the requirements for a new or modified system

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The End-User Systems Development Life Cycle

Any systems development project in which the primary effort is undertaken by a combination of business managers and users

End-user-developed systems can be structured as complementary to, rather than in conflict with, existing and emerging information systems

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Computer-aided software engineering (CASE) Tools that automate many of the tasks

required in a systems development effort and enforce adherence to the SDLC

Use of Computer-Aided Software Engineering (CASE) Tools

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Use of Computer-Aided Software Engineering (CASE) Tools

Table 8.2: Advantages and Disadvantages of CASE Tools

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Object-Oriented Systems Development OOSD

The approach that combines the logic of the systems development life cycle with the power of object-oriented modeling and programming.

Object-oriented systems development typically involves: Identifying potential problems and opportunities within the

organization that would be appropriate for the OO approach

Defining the kind of system users require Designing the system

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Object-Oriented Systems Development

Object-oriented systems development typically involves (continued): Programming or modifying modules Evaluation by users Periodic review and modification

Systems Investigation

Chapter 8.3

Key Terms

• Systems request form• Feasibility analysis• Technical feasibility• Economic feasibility• Legal feasibility• Operational feasibility

• Schedule feasibility• Systems investigation report

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Systems Investigation

Identify potential problems and opportunities and consider them in light of the goals of the company.

Formal procedures for initiating systems development typically include a Systems Request Form: Identifies problems in or opportunities for

the system States objectives of systems

investigation Presents an overview of the proposed

system Projects expected costs and benefits of

the proposed system

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Feasibility Analysis

Feasibility analysis is the assessment of the technical, economic, legal, operational, and schedule feasibility of a project

Technical feasibility Economic feasibility Legal feasibility Operational feasibility Schedule feasibility

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Systems investigation report A summary of the results of the systems

investigation and the process of feasibility analysis and recommendations of a course of action.

Feasibility Analysis

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The Systems Investigation Report

Figure 8.8: A Typical Table of Contents for a Systems Investigation Report

Systems Analysis

Chapter 8.4

Key Terms

• Structured interview• Unstructured interview• Direct observation• Questionnaires• Data analysis• Data-flow diagram (DFD)

• Requirements analysis• Asking directly

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Systems Analysis

Data Collection Seeks additional information

about problems or needs. Internal and External Sources

Data Analysis Data Modeling with entity-

relationship diagrams Activity Modeling with data-flow

diagrams

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Data Collection

Identifying sources of data Internal sources External sources

Collecting data Interviews Direct observation Questionnaires

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Data Collection

Figure 8.9: Internal and External Sources of Data for Systems Analysis

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Collecting Data

Structured interviews Questions are written in advance

Unstructured interviews Questions are not written in advance

Direct observation Watching the existing system in action by one

or more members of the analysis team

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Data Analysis

Questionnaires Gathering data when the data sources are spread

over a wide geographic area Data modeling

Entity-relationship (ER) diagrams Activity modeling

Data-flow diagrams (DFDs) A model of objects, associations, and activities by

describing how data can flow between and around various objects

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Data Analysis

Figure 8.11: Data and Activity Modeling (a) An entity-relationship diagram

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Data Analysis

Figure 8.11: Data and Activity Modeling (continued) (b) A data-flow diagram

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Data Analysis

Figure 8.11: Data and Activity Modeling (continued)(c) A semantic description of the business process

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Requirements Analysis

Requirements analysis Determination of user, stakeholder, and

organizational needs Asking directly

An approach to gather data that asks users, stakeholders, and other managers about what they want and expect from the new or modified system

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Object-Oriented Systems Analysis

Identifying problems or potential opportunities Identifying key participants and collecting data Instead of analyzing the existing system using

data-flow diagrams and flowcharts, an object-oriented approach is used

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Object-Oriented Systems Analysis

Figure 8.13: Generalization/Specialization Hierarchy Diagram for Single and Tandem Kayak Classes

Systems Design

Chapter 8.5

Key Terms

• Logical design• Physical design• Request for proposal (RFP)• Design report

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Systems Design

Answers question “How will the information system solve a problem?”

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

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Request for Proposal (RFP)

A document that specifies in detail required resources such as hardware and software

Sent to outside vendors

Systems Design Alternatives

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The Design Report

Design report: the result of systems design Contains system specifications

System specifications include technical description of: System outputs, inputs, and user

interfaces Hardware, software, databases,

telecommunications, personnel, and procedure components and the way these components are related

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The Design Report

Figure 8.17: A Typical Table of Contents for a Systems Design Report

Systems Implementation

Chapter 8.6

Key Terms

• Make-or-buy decision• Site preparation• Data preparation or data

conversion• Installation• Start-up

• Direct conversion (AKA Plunge or direct cutover)

• Phase-in approach, orpiecemeal approach

• Pilot start-up• Parallel start-up• User acceptance document

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Systems Implementation

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Acquiring Software: Make or Buy?

Externally developed software In-house developed software Blend of external and internal software

development Renting software Reusing software from other development efforts

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Site Preparation

Preparation of the location of a new system Making room for a computer in an office Special wiring and air conditioning Special flooring Additional power circuits

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Data Preparation

Also called data conversion Ensuring all files and databases are ready to be

used with new computer software and systems

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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

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Start-Up

The process of making the final tested information system fully operational

Direct conversion (also called plunge or direct cutover) The process of stopping the old system and

starting the new system on a given date Phase-in approach

Slowly replacing components of the old system with those of the new one

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Start-Up

Pilot start-up The process of running the new system for one

group of users rather then for all users Parallel start-up

The process of running both the old and new systems for a period of time, comparing the new system’s output with the old system’s, reconciling any differences, and finally eliminating the old system

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Start-up

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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

Systems Operation & Maintenance

Chapter 8.7

Key Terms

• Systems operation

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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

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Systems Maintenance

Reasons for the need of Maintenance: Bugs or errors in the program New requests from users and

stakeholders Technical and hardware problems Change in operating system or

hardware Changes in business processes Corporate mergers and acquisitions Government regulations (HIPAA)

Systems Review

Chapter 8.8

Key Terms

• Event-driven review• Time-driven review

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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

Questions?

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