Database Principles & Design By Colin Ritchie

advertisement

Management Information

Systems

By Effy Oz & Andy Jones

Chapter 11: System Planning and

Development

www.cengage.co.uk/oz

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Objectives

• Explain the importance of and steps in IT planning

• Describe the systems development life cycle, which is the traditional approach to systems development

• Explain the challenges involved in systems development

• List the advantages and disadvantages of different system conversion strategies

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Objectives (continued)

• Enumerate and explain the principles of agile systems development methods

• Explain the concept of systems integration

• Discuss whether IS professionals should be certified

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Planning Information Systems

• Enterprise ISs gaining in popularity

• High risk involved in implementation

• Successful integration of system vital

• Planning of IS necessary

• Align IS and organizational strategies

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Steps in Planning Information Systems

• IS planning includes several key steps

– Create IS mission statement

– Articulate vision for IS

– Create IS plans

– Create operations plan

– Create budget

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Steps in Planning Information

Systems (continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Steps in Planning Information

Systems (continued)

Mission statement

: most important overarching goal of organization

• IS mission statement describes goal of IS

– Should be compatible with organizational mission statement

• CIO develops strategic plan for implementation

• Goals broken down into objectives

• Objectives broken down to operational details

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Steps in Planning Information

Systems (continued)

• IT planning similar to planning of other resources

• Growing proportion of IT funds spent on software

– More purchasing

– Less developing in-house

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

The Benefits of Standardization in

Planning

• Major goal of planning is standardization

• Many benefits

– Cost savings

• Better bargaining power

• Applies to hardware and software

– Efficient training

• Smaller variety of software

– Efficient support

• More specialization

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

From Planning to Development

• After planning decide how to obtain systems

– Usually software

• Approaches to systems development universal

– Two approaches

• Systems development life cycle (SDLC)

• Nontraditional methods

• Agile methods more efficient

Prototyping

: fast development of application based on initial requirements

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

The Systems Development Life Cycle

• Large ISs conceived with

systems development life cycle (SDLC)

• SDLC also known as waterfall development

– Consists of sequential phases

• Organizations sometimes take shortcuts

• Four major phases

– Analysis

– Design

– Implementation

– Support

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

The Systems Development Life Cycle

(continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Analysis

Systems analysis

: five-step process

– Investigation

– Technical feasibility study

– Economic feasibility study

– Operational feasibility study

– Requirements definition

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Analysis (continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Analysis (continued)

• First step is investigation

– Determine if system necessary

– Small team interviews employees

Feasibility studies

: conducted after IS warranted

– Technical feasibility

• Determine if components exist

• Adequate hardware

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Analysis (continued)

• Economic feasibility study

Cost/benefit analysis

: spreadsheet showing costs

• Benefits must outweigh costs

Return on investment (ROI)

: most accurate economic analysis

• Difference between stream of benefits and costs

• Many benefits are intangible

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Analysis (continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Analysis (continued)

• Operational feasibility study

– Determine how new system will be used

Organizational culture

: general tone of corporate environment

– System compatibility with culture

• Requirements definition

– Project team installed

System requirements

: functions expected from system

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Design

• Second step in systems development is design

Systems design

– Description

: three steps

– Construction

– Testing

• If purchasing system must determine how to adapt

– Construction requires changing programming code

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Design (continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Design (continued)

• Symbols used to communicate ideas

– Visual information grasped more quickly

Data flow diagram

(

DFD

): describes flow of data

– Four symbols

• External entities

• Processes

• Data stores

• Direction of data flow

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Design (continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Design (continued)

• DFD symbols

– External entities are external individuals and groups

– Processes are events that change data

– Data store is resting data

– Data flow is direction that data moves

• Simplicity of DFD is advantage

• DFD suitable for describing non-computer based

IS

• DFD cannot describe system completely

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Design (continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Design (continued)

Unified modeling language (UML)

: de facto standard for diagramming

– Helps developers communicate features

– Provides standard symbols and notations

– Consists of diagrams describing software

• Use case

• Class

• Interaction

• State

• Activity

• Physical components

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Design (continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Design (continued)

• Construction

– Mostly programming

– Takes months to years

– Testing done on completed modules

• Walk-through logic of program

• Simulation of actual program execution

• System testing

– Test entire integrated system

– Try to “outsmart” system

– Poor testing causes many failures

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Implementation

Implementation

: Two steps

– Conversion

– Training

Conversion

: switching old system to new

– Four basic strategies

Parallel conversion

: old system used with new system at first

Phased conversion

: break IS into modules and integrate one at a time

Cut-over conversion

: immediately replace all

Pilot conversion

: introduce in one business unit at a time

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Implementation (continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Support

Support

: two responsibilities

– Maintenance

• Post-implementation debugging

• Updates

• Adding postponed features

– User help

– Longest phase of system life cycle

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Agile Methods

Agile methods

: alternatives to SDLC

– Treat software development as series of contacts with users

– Fast development of software

– Improve software after user specifications received

– Iterative programming

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Agile Methods (continued)

• Popular agile methods

– Extreme programming (XP)

– Adaptive software development (ASD)

– Lean development (LD)

– Rational unified process (RUP)

– Feature driven development (FDD)

– Dynamic systems development method (DSDM)

– Scrum

– Crystal

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Agile Methods (continued)

• Agile method risks

– Analysis phase limited or eliminated

• Risk of incompatibilities

– Less documentation

• Difficult modification

• Manifesto for Agile Software Development prioritizes individuals and interactions over processes

• Light but sufficient development process

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Agile Methods (continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Agile Methods (continued)

• User involvement encouraged throughout process

• Test modules immediately after completion

• Communication with users informal

• Two programmers per module

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

When to Use Agile Methods

• Best to use agile method

– When system is small

• Analysis less important

• Small investment of resources

– For unstructured problems

– Users cannot specify all requirements at start

• Unfamiliar with technology

• Difficult to conceptualize

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

When Not to Use Agile Methods

• Do not use agile methods when

– System is large

• System failure entails great financial loss

– Designed to interface with other systems

• SDLC recommended for complex systems

• Documentation is key

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

When Not to Use Agile Methods

(continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Systems Integration

Systems integration

: combine disparate systems

– Examines needs of entire organization

– Allows data to flow between units

– Some service companies specialize in this

– Integration more challenging than development

– Interface legacy systems with new systems

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Systems Integration (continued)

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Systems Integration (continued)

• Systems integrators must be skilled in hardware and software

• Difficult to overcome incompatibility issues

• Systems integration may span several organizations

• Integration with telecommunications

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Summary

• IT planning important because of high investment rate

• Standardization important part of IT planning

• Systems development life cycle (SDLC) has well-defined phases

• Purpose of systems analysis is to determine needs the system will satisfy

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Summary (continued)

• Feasibility studies determine if system is possible and desirable

• System requirements detail features needed

• Developers outline system components graphically

• Unified Modeling language used to create model of desired system

• Implementation includes training and conversion to new system

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Summary (continued)

• Support entails maintenance and satisfying changing needs

• Agile methods are popular alternative to traditional systems development cycle

• Systems integration more complicated than systems development

• Great responsibility of IS professionals results in certification requirements

Use with

Management Information Systems 1e

By Effy Oz & Andy Jones ISBN 9781844807581

© 2008 Cengage Learning

Download