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10-1 © Prentice Hall, 2004
Chapter 10:Chapter 10:Selecting the Best Alternative Selecting the Best Alternative
Design StrategyDesign Strategy
Object-Oriented Systems Analysis and Design
Joey F. George, Dinesh Batra,
Joseph S. Valacich, Jeffrey A. Hoffer
10-2Chapter 10 © Prentice Hall, 2004
Chapter ObjectivesChapter Objectives
After studying this chapter you should be able to:– Describe the different sources of
software.– Assemble the various pieces of an
alternative design strategy.– Generate at least three alternative design
strategies for an information system.
10-3Chapter 10 © Prentice Hall, 2004
Chapter Objectives Chapter Objectives (Continued)(Continued)
After studying this chapter you should be able to:– Select the best design strategy using
qualitative and quantitative methods.– Update a Baseline Project Plan (BPP)
based on the results of the analysis phase.
10-4Chapter 10 © Prentice Hall, 2004
10-5Chapter 10 © Prentice Hall, 2004
Deliverables for Design Deliverables for Design Strategy SelectionStrategy Selection
Why three? One for high-functionality high-cost solution, one for minimum functionality low-cost solution, and one for middle-of-the-road
10-6Chapter 10 © Prentice Hall, 2004
Features are determined from requirements.
Constraints pertain to limitations on development efforts.
10-7Chapter 10 © Prentice Hall, 2004
Generating a Design StrategyGenerating a Design Strategy
Divide requirements (obtained during requirements gathering and structuring) into sets of capabilities, categorized by level of necessity
Enumerate different potential implementation environments (hardware and system software platforms)
Propose different sourcing possibilities for obtaining the necessary software
10-8Chapter 10 © Prentice Hall, 2004
What Is Outsourcing?What Is Outsourcing?
The practice of turning over responsibility of some or all of an organization’s information systems applications and operations to an outside firm
Can produce cost savings for the client, by leveraging the outsourcer’s economies of scale
10-9Chapter 10 © Prentice Hall, 2004
What Is an RFP?What Is an RFP?
Request for Proposal – a document provided to vendors to ask them to propose hardware and/or software products or services that will meet the requirements of an organization’s new information system
Based on vendor bids, analyst selects best candidates
10-10Chapter 10 © Prentice Hall, 2004
Main Sources of SoftwareMain Sources of Software
– Hardware Manufacturers– Prepackaged Software Producers– Custom Software Producers– Enterprise Solutions Software– In-house Development
10-11Chapter 10 © Prentice Hall, 2004
10-12Chapter 10 © Prentice Hall, 2004
Hardware ManufacturersHardware Manufacturers
IBM is the leader in software sales and services
Hardware manufacturers tend to focus on system software and utilities
10-13Chapter 10 © Prentice Hall, 2004
Prepackaged SoftwarePrepackaged Software
Microsoft is the leader in prepackaged software production.
Prepackaged software is off-the-shelf software.
Often, prepackaged software is turnkey software (i.e., not customizable) .
10-14Chapter 10 © Prentice Hall, 2004
Many factors go into selection of off-the-shelf software, many of which are relevant for other software purchases.
Vendor support and viability are always among the most important criteria.
10-15Chapter 10 © Prentice Hall, 2004
Custom Software ProducersCustom Software Producers
Firms like Accenture and EDS are leading custom software producers.
Consulting firms that develop software to meet the client’s specific requirements
Consulting firms are usually called when the client company does not have in-house expertise or manpower available to develop the system.
10-16Chapter 10 © Prentice Hall, 2004
Enterprise Solutions SoftwareEnterprise Solutions Software
Enterprise Resource Planning (ERP) software – integrates individual traditional business functions modules enabling a single seamless transaction cut across functional boundaries
SAP AG is the leading vendor of ERP systems
10-17Chapter 10 © Prentice Hall, 2004
In-house DevelopmentIn-house Development
If sufficient system development expertise with the chosen platform exists in-house, then some or all of the system can be developed by the organization’s own staff
Often, there are a variety of sources that are used, with in-house staff playing a role as well as consultants or ERP vendors
10-18Chapter 10 © Prentice Hall, 2004
10-19Chapter 10 © Prentice Hall, 2004
Validating Purchased Software Validating Purchased Software InformationInformation
Use a variety of information sources:– Vendor’s proposal– Running software through a series of tests– Feedback from other users of the vendor’s
product– Independent software testing services– Articles in trade publications
10-20Chapter 10 © Prentice Hall, 2004
Hardware and System Software Hardware and System Software IssuesIssues
Reasons to stay with old platform– Lower cost installation– Familiarity of IS staff– Ease of integration with existing applications– Less need for data and software conversions
10-21Chapter 10 © Prentice Hall, 2004
Hardware and System Software Hardware and System Software Issues (Continued)Issues (Continued)
Reasons to change to new platform– New components may not be compatible with
old platform– New platform provides opportunity for
organization to improve its technology holdings– New platform serves as impetus for significant
business process changes
10-22Chapter 10 © Prentice Hall, 2004
Example: Pine Valley FurnitureExample: Pine Valley Furniture
• System requirements categorized into mandatory, essential, and desired capabilities
• Constraints established
• Low-end, high-end, and moderate design strategies are generated
• Weighted approach used to compare alternative design strategies
10-23Chapter 10 © Prentice Hall, 2004
10-24Chapter 10 © Prentice Hall, 2004
10-25Chapter 10 © Prentice Hall, 2004
Application Server/Object Framework is the highest scoring alternative
10-26Chapter 10 © Prentice Hall, 2004
3-Tier architecture is scalable, and consists of a Web server providing the interface to the Internet in the 1st tier, an application server running the business rules of the application in the 2nd tier, and the corporate databases in the 3rd tier
10-27Chapter 10 © Prentice Hall, 2004
BPP goes through significant update as a result of design strategy generation and selection.
The System Description section is changed the most, and all sections are refined and altered.
10-28Chapter 10 © Prentice Hall, 2004
Cost-benefit analysis goes through significant update and revision after selecting a design strategy.
10-29Chapter 10 © Prentice Hall, 2004
Schedule estimation goes through significant update and revision after selecting a design strategy.
10-30Chapter 10 © Prentice Hall, 2004
RecapRecap
After studying this chapter we learned to:– Describe software sources.– Assemble design strategies.– Generate three alternative design strategies.– Select the best design strategy qualitatively and
quantitatively.– Update a baseline project plan.