8-1 © Prentice Hall, 2007 Topic 8: Selecting the Best Alternative Design Strategy Object-Oriented Systems Analysis and Design Joey F. George, Dinesh Batra, Joseph S. Valacich, Jeffrey A. Hoffer

Topic © Prentice Hall, 2007 Chapter Objectives Af ter 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.

Topic © Prentice Hall, 2007 Chapter Objectives (Continued) Af ter 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.

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Topic © Prentice Hall, 2007 Deliverables for Design Strategy Selection Why three? One for high-functionality high-cost solution, one for minimum functionality low-cost solution, and one for middle-of-the-road

Topic © Prentice Hall, 2007 Features are determined from requirements. Constraints pertain to limitations on development efforts.

Topic © Prentice Hall, 2007 Generating 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

Topic © Prentice Hall, 2007 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

Topic © Prentice Hall, 2007 Main Sources of Software – IT Service Firms – Packaged Software Providers – Custom Software Producers – Enterprise Solutions Software – Open Source Software – In-house Development

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Topic © Prentice Hall, 2007 Information Technology Service Firms IBM is a leading IT service firm Help develop custom information systems for internal use Develop, host and run applications for clients Provide other services

Topic © Prentice Hall, 2007 Package Software Providers Microsoft is a leading package software provider Packaged software is off-the-shelf software Range from general-purpose to nrrow-niche focus May be turnkey (unmodifiable) or modifiable

Topic © Prentice Hall, 2007 Custom Software Producers Firms like Accenture and CapGemini 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.

Topic © Prentice Hall, 2007 Enterprise 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

Topic © Prentice Hall, 2007 Open Source Software Freely available Includes both final product and source code Developed by a community rather than a company Examples: mySql (database), Firefox (browser), Linux (operating system) Profit potentials: – Maintenance and service – Free version with fewer features, for-cost version with more features

Topic © Prentice Hall, 2007 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

Topic © Prentice Hall, 2007 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.

Topic © Prentice Hall, 2007 In-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

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Topic © Prentice Hall, 2007 Validating Purchased Software Information 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

Topic © Prentice Hall, 2007 Hardware and System Software Issues 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

Topic © Prentice Hall, 2007 Hardware and System Software 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

Topic © Prentice Hall, 2007 Example: 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

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Topic © Prentice Hall, 2007 Server/Object Framework is the highest scoring alternative

Topic © Prentice Hall, Tier architecture is scalable, and consists of a Web server providing the interface to the Internet in the 1 st tier, an application server running the business rules of the application in the 2 nd tier, and the corporate databases in the 3 rd tier

Topic © Prentice Hall, 2007 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.

Topic © Prentice Hall, 2007 Cost-benefit analysis goes through significant update and revision after selecting a design strategy.

Topic © Prentice Hall, 2007 Schedule estimation goes through significant update and revision after selecting a design strategy.

Topic © Prentice Hall, 2007 Recap Af ter 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.