introduction to management information systems chapter 6 system development htm 304 spring 06

Introduction to Management Information

Systems

Chapter 6 System Development

HTM 304

Spring 06

2

What Systems to be developed

Many different types of systems in the organization

EAI

IT Infrastructure

InternetOther

organizations

Inter –OrganizationalInformation Systems

(B2B, SRM, etc.)

HR

Mar

ketin

g

Ope

ratio

ns

Pur

chas

ing

Oth

ers

Integrated Systems(e.g. ERP, etc)

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System Development Fundamentals

System Development – a process for creating and

maintaining information systems (IS)

-- Also called System Analysis and Design (Dr. Fang

& Kumar, Summer 2007)

Developing an IS involves all 5 components:

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Personnel Involved

Constant interaction between Users (MIS, HTM 304) and IT professionals (System Analysis & Design, HTM 425)

Constant interaction between Users (MIS, HTM 304) and IT professionals (System Analysis & Design, HTM 425)

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Video – System Development

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Think Big About System Development

Many students are new to the systems development process due to working with personal computer tools.

The scope of work is large with large-scale corporate information systems and may be global with different languages and cultures.

Management of resources is a critical success factor.

Comprehensive processes are required for project staff to follow and adhere to in order to successfully meet project and systems objectives.

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Think Big (cont)

Three software sources Off-the-shelf

Off-the shelf-with adaptation

Tailor-made

Major IS rarely off-the-shelf due to involvement of company people and resources

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System Development Is Challenging

Systems development difficult and risky

Many projects never finished

Some projects finish 200-300% over budget

Some projects finish on schedule and within budget but don’t meet the goals

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System Development Challenges

Difficulties in determining requirements

Changes in requirements

Scheduling and budgeting difficulties

Changing technology

Diseconomies of scale

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Systems Development Methodologies

There are many different system

development processes

System Development Life Cycle (SDLC)

Rapid Application Development (RAD)

Object-oriented System Development (OOD)

Extreme Programming (XP)

Information Systems Differ

No single process works for all situations

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Scales of Information Systems

System Type Description

PersonalSupports one person with limited set of requirements

WorkgroupSupports group of people normally with a single application

EnterpriseSupports many workgroups with many different applications

InterenterpriseSupports many different organizations with many different cultures, countries and heritages

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The 5-Phase Version of SDLC in our book

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System Definition Phase Tasks

Define project

Goals and objectives

Scope – statement of work

Assess feasibility

Cost (budget)

Schedule

Technical

Organizational feasibility

Form a project team

Project manager

In-house IT staff

Outside consultants and staff (as needed)

User representatives (management and staff)

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SDLC Requirement Analysis Phase

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Requirement Analysis Phase Tasks

The most important phase in the system development process is determining system requirements.

If the requirements are wrong, the system will be wrong.

If the requirements are determined completely and correctly, then the design and implementation will be easier and more likely to result in success.

Seasoned and experienced system analysts know

how to conduct interviews to bring such

requirements to light.

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Obtain User Approval Before You Move-on

Once the requirements have been specified, the users must

review and approve them before the project continues.

The easiest and cheapest time to alter the information system

is in the requirements phase.

Changing a requirement in the implementation phase may

require weeks of reworking applications components and the

database.

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Component Design Phase

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Component Design Phase

Each of the five components is designed in this stage.

The team designs each of the five components by

developing a list of alternatives.

Each alternative is evaluated against the requirements.

Typically the best alternative that meets the

requirements is selected.

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Hardware Design

Team determines specifications

for hardware they want to

acquire

Team NOT designing hardware

Typically, large company has

some type of computer network

infrastructure

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Hardware Networking Alternatives

PC or LANs over public

Internet

Point-to-point leased lines

Lease time on some type of

PSDN

Create Virtual Private

Network (VPN) over

Internet

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Program Design

Depends on program source

Off-the-shelf – team

must assess products

and evaluate them

against requirements

Off-the-shelf with alteration

- team IDs products and

assesses alterations

Custom-design programs –

team write specifications

(documentation) for program code

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Database and Procedure Design

Database design

Convert database design to data model

If off-the-shelf DB, little design needed

Procedure design

Procedures must be developed for system users and operations

personnel to follow

Procedures typically address

Normal processing: procedures for using the system to accomplish

business tasks

Backup: user procedures for backing up data and other resources

Failure recovery: Procedure to continue operation when system fails

and procedures to convert back to the system after recovery

Database design

Convert database design to data model

If off-the-shelf DB, little design needed

Procedure design

Procedures must be developed for system users and operations

personnel to follow

Procedures typically address

Normal processing: procedures for using the system to accomplish

business tasks

Backup: user procedures for backing up data and other resources

Failure recovery: Procedure to continue operation when system fails

and procedures to convert back to the system after recovery

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People Component -- Design of Job Descriptions

Job descriptions needed for both users

and operations personnel

New IS may require new jobs

Organizations may have to add new

duties and responsibilities due to

information systems changes and

enhancements

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Implementation Phase

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Comparison of Design and Implementation

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System Conversion

4 ways to implement system conversion

Pilot – Implement entire system on limited

portion of the business

Phased- New system installed in pieces

across organization

Parallel – New system runs in parallel with

old system for a while

Plunge – Old system turned off and new

system turned on immediately

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Maintenance Phase

New needs

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Information System Maintenance

Either fixing system to make it do

what is expected

Or adapting system to changing

requirement

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Problems with SDLC

The most formal procedure to develop large IS project

Systems development seldom smooth

Sometimes need to crawl back up waterfall

Difficulty documenting requirements in usable way

Scheduling and budgeting difficult, especially for large projects

with large SDLC phases

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Review of SDLC

What are the five phases?

Which phase is the most important?

Briefly describe the five phases.

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Other Developing Methods

Rapid application development (RAD)

Object-oriented systems development (OOD)

Extreme programming (XP)

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RAD

Basic idea - break up design and implementation phases of SDLC into smaller pieces

Use iterative process – build a piece of the system, test it and then make it better

Use iterative process – build a piece of the system, test it and then make it better

Get user input with every iteration

- You are always involved.

Get user input with every iteration

- You are always involved.

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RAD – Extensive Use of Prototypes

Extensive use of prototypesA mock-up of aspect of new system and could be:

-- Form -- Report

-- Database Query --User Interfaces

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E-R modeling of the Data Form

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CASE Tools

CASE: Computer-assisted systems engineering

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Summary of RAD Characteristics

Design / implement / fix development process

Continuous user involvement throughout

Extensive use of prototypes

Joint Application Design (JAD)

Use of CASE Tools

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Object-Oriented Systems Development (OOD)

Began after RAD – mid 1990s

Driven by new program development method – Object-Oriented

Programming (OOP)

A series of diagramming techniques called Unified Modeling Language

(UML) facilitates OOP development.

Example:

Unified Process

(UP)

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Extreme Programming

Emerging Technique Developing Computer Programs

Not useful for large scale development system requiring business

processes & procedures (or at least not yet realized)

There are cases where organizations have used it successfully in

developing application programs.

Three main characteristics

1) Customer-Centric

2) Just-In-Time (JIT) Design

3) Paired Programming

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Compare Development Techniques