Chapter 10 – Developing Information Systems Information Systems, First Edition John Wiley & Sons,...

Chapter 10 – Developing Information Systems

Information Systems, First Edition John Wiley & Sons, Inc

by France Belanger and Craig Van SlykeContributor: Brian West, University of Louisiana

at Lafayette

10-1Copyright 2012 John Wiley & Sons, Inc.

The $6,000,000,000 software bugIn August 2003, the largest power blackout in North American history hit the northeastern US and southeastern Canada.At least eleven people died as a result of the blackout. Total cost: $6 billion. Unfortunately, in this case a software bug caused the alarm system to malfunction. This started a cascade of errors that led to over 50 million people losing electrical power. The lack of power also led to water supply problems, and the shutdown of major transportation systems, including railroads and airlines. Gas stations could not dispense fuel. Cell phone service was interrupted (although wired phones continued working).

Copyright 2012 John Wiley & Sons, Inc. 10-2

Focusing Questions

• Have you ever experienced software that did not operate correctly? What consequences did you experience?

• What can be done to limit software errors?• Why is it important to catch software errors

early in the development process?


Time, Cost and Quality

• “You want it fast, good and cheap? Pick any two.”

• Time:

• Cost:

• Quality:


Determining requirements

Determining system requirements is a major step in the software development process. One method for uncovering requirements is to interview the intended users of the software. Suppose that a club you belong to wants to create a system for keeping track of members. Get in pairs. One of you acts as the interviewer who is trying to discover requirements. The other acts as the user. Document at least ten requirements for the system.


Software Development

• It is useful to have a framework for planning, structuring and controlling software development projects called software development methodologies

• Software development methodology provides


Traditional SDLC• The traditional systems development life cycle

(SDLC) provides a disciplined “waterfall” method

• One phase flows as inputs into the next phase


Planning

Requirements

Development

Implementation

MaintenanceFigure 10.1- Traditional Systems Development Life Cycle

Planning Phase

• The goal of the planning stage is to define the overall goal and scope of the system and determine the feasibility of the project.

• Determine feasibility–– – – –


Planning Outputs

• Project initiation document specifies the high-level goals of the system and describes the business case for the system

• The feasibility analysis results are often included in the business case

• The project management plan documents the scope of the project, identifies major tasks and resources


Requirements Phase

• The goal of the requirements phase is to uncover and document the functions that the system should provide and desired levels of performance.

• __________________describe how the system should interact with users and other systems

• ____________________are related to constraints on the system (how well it should perform)


Requirements Elicitation

• Gathering requirements from various stakeholders and is a primary task in the requirements phase

• Often a time consuming and error-prone process

• Requirements may (will) change during the process

• It is very important to understand the system’s process


Requirements Phase Outputs

• Specification of the system’s functional and non-functional requirements

• Use cases or “system shall” statements (text or diagram form)

• “The system shall allow teachers to enter student grades.”


Instructor

Enter roster

Set weights

Student

Enter grades

Edit grades

View grades

Figure 10.2- Use Case Diagram Example

Design Phase

• The main goal of the design phase is to describe in detail how the system will meet the requirements specified

• The focus is on how the system will satisfy requirements

• Logical system design includes elements of what the system will do, includes abstract models


Design Phase Outputs

• System design document is a major deliverable of the design phase

• Describes, in detail, the system requirements, operating environment, database design, user interface, processing logic

• Other deliverables include an implementation plan and a training plan


Development Phase

• Phase in which the system is actually constructed

• The software is written, databases are created, and any necessary hardware is installed

• Integrate the new system with existing information systems

• System testing is a critical part of the development phase


Development Phase Outputs

• The development phase’s deliverables include

• Data and files for testing and documentation on how the software components interact with each other and external systems


Implementation Phase

• The goal of the implementation phase is to make the system operational in a production environment

• Notify users of the rollout of the new system• User training is also an important activity• Main deliverable of the implementation phase

is the system itself


Implementation Approaches

• _______________(also called immediate changeover): At a specific point in time, the old system is no longer used and is replaced with the new system.

• ________________: Both the old and new systems operate for some period of time

• ________________: The new system is implemented in stages

• _________________: The new system is implemented in a business unit


Maintenance Phase

• The goal of this phase is ensuring that the system operates properly to meet current needs

• Usually the longest, most costly phase of the life-cycle

• Fix any problems that are uncovered and modify or add to the programs to meet new needs


Advantages and disadvantages of the SDLC

The traditional SDLC has been around for a long time (that is why it is called “traditional”) and has been used successful for many systems development projects. However, it is not without its drawbacks. With a partner, research the SDLC approach and develop a list of three advantages and three disadvantages to the traditional SDLC. Be prepared to share your list.


Prototyping

• Deals with aspects of a full methodology; it is not a complete, stand-alone methodology

• It is not necessary to have a full understanding of all requirements

• A small-scale mock-up of the system (called the _____________) is built and reviewed

• Flaws are pointed out and the prototype is refined and reviewed


Benefits of Prototyping

• Increased stakeholder involvement is a major benefit – Stakeholders know the particular business area – Stakeholder involvement may increase

satisfaction with the final system• Prototyping is also potentially more effective

for uncovering system requirements– Important when requirements are unclear,

ambiguous or difficult to define


Rapid Application Development (RAD)

• Intended to develop systems more quickly

• Active user involvement is a key aspect – Determine high level

requirements – Build prototype– Get feedback– Refine prototype


Rapid Application Development Cycle

Figure 10.3- Rapid Application Development Cycle

Spiral Model• Iterative version of the standard “waterfall” SDLC• A risk-driven model, which focuses reducing

project risk by identifying risks and ways to reduce those risks throughout the development process


– Identify objectives, alternative approaches and constraints

– Evaluate the alternatives and identify and resolve risks

– Develop and verify the deliverables from this iteration

– Plan the next iteration

Spiral Model

Copyright 2012 John Wiley & Sons, Inc. 10-25Figure 10.4- Spiral Model

Comparing Methods

Pick one of the alternative software development methodologies described in the chapter. Compare it with the traditional SDLC. Find at least three ways in which they are similar, and three ways in which they are different. Be prepared to share your answer.


Build or Buy Decision


Degree of customization

Development and implementation costs

Length of time to implement

Fit with existing business processes

Fit with requirements

COTSCustom

builtHybrid

Figure 10.5- Comparing COTS and Custom Development

• Benefit of custom built

• Hybrid solutions

• COTS

How open source software impacts build vs. buy

Open source software is software that provides access to the program’s code, which means that it can be freely modified. Often organizations must decide whether to build custom software or purchase a commercial software package. In pairs, discuss how open source software might impact the “build vs. buy” decision. Prepare a bullet list of your findings.


Using Open Source in Business

• Open source software is software that allows users to access the underlying source code for an application and at no cost

• Organizations use open source for potential cost savings

• Reduce dependency on proprietary software• Reliability and open standards


What to outsource

Outsourcing occurs when a company turns to an outside vendor to provide some service. While the definition of outsourcing is easy to understand, deciding what to outsource is much harder. For each of the business scenarios below, decide whether the system or operation should be outsourced. Explain your answer.


What to outsource

Organization System/function

1. Engineering company Payroll and benefits management system

1. Regional beer brewery Customer relationship management

1. University Learning management system (e.g. Blackboard, Moodle)

1. Financial portfolio management company Investment analysis software

1. Public radio station Donor management system


Outsourcing Information Systems

Information technology outsourcing occurs when an organization goes to an outside company to provide IT services that were previously provided internally.


Benefits and Risks of Outsourcing

• Gain access to expertise not available in-house

• Potential cost savings• Shifting fixed costs to

variable costs• Effective way to manage

capacity• Focus on core activities• Potential for 24-hour

productivity

• Loss of internal competencies

• Becoming dependent on service provider (lowers bargaining power)

• Opportunistic behavior by service provider

• Lower morale of remaining workers

• Confidentiality may be compromised


Making the Outsourcing Decision

The outsourcing decision is often difficult and complicated•How mature is the IT system in question?

– Systems that have been around a long time are better candidates for outsourcing.

•How significant is the system to the organization’s competitive advantage?

– One common reason for outsourcing is to allow the organization to concentrate on core activities


Making the Outsourcing Decision

• How does the organization’s IT capability compare with competitors’?– In cases where an organization has relatively weak

IT capabilities it may be better to outsource

• Are there cost advantages to outsourcing?– Even if there are no savings through outsourcing,

it may still be a good idea if outsourcing allows the organization to focus on critical areas or if the organization lacks the necessary capabilities.


Geographic Considerations

• __________________involves using a vendor that provides services from a location outside the client organization’s region– Reduces cost because of lower wages– May create backlash (shipping jobs overseas,

language barriers)• __________________occurs close to the client’s

home location• __________________is outsourcing to a firm

located in the same country


Summary

• Software development methodologies provide discipline to the development process by defining processes, roles and deliverables.

• The traditional systems development life-cycle is a semi-sequential, phased approach. There are different versions of the traditional SDLC.

• The SDLC described in this chapter consists of five phases, planning, requirements, development, implementation and maintenance.


Summary

• Alternatives to the traditional SDLC include prototyping, rapid application development, and the spiral model.

• The decision whether to build custom software or purchase commercial, off-the-shelf software is complex.

• Open source software allows users to access the underlying source code for the application, which allows users to modify the program.

• Open source software is usually free, although some companies charge a fee for ongoing support.


Summary• Outsourcing occurs when an outside organization provides

IT services that were previously provided internally.• Outsourcing models include full (complete) outsourcing,

process-based outsourcing, personnel outsourcing, project-based outsourcing and application outsourcing.

• There are both benefits and risks associated with outsourcing.

• Factors affecting the outsourcing decision include the maturing of the system, the systems significance to the organization’s competitive advantage, the organizations IT capability and cost.


Copyright 2012 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein.

10-40Copyright 2012 John Wiley & Sons, Inc.

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