1. 10-1 © Prentice Hall, 2004 Chapter 10: Selecting the Best Alternative Design Strategy Object-Oriented Systems Analysis and Design Joey F. George, Dinesh Batra, Joseph S. Valacich, Jeffrey A. Hoffer

2. Chapter 10 10-2 © Prentice Hall, 2004 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.

3. Chapter 10 10-3 © Prentice Hall, 2004 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.

4. Chapter 10 10-4 © Prentice Hall, 2004

5. Chapter 10 10-5 © Prentice Hall, 2004 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

6. Chapter 10 10-6 © Prentice Hall, 2004 Features are determined from requirements. Constraints pertain to limitations on development efforts.

7. Chapter 10 10-7 © Prentice Hall, 2004 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

8. Chapter 10 10-8 © Prentice Hall, 2004 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

9. Chapter 10 10-9 © Prentice Hall, 2004 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. Chapter 10 10-10 © Prentice Hall, 2004 Main Sources of Software – Hardware Manufacturers – Prepackaged Software Producers – Custom Software Producers – Enterprise Solutions Software – In-house Development

11. Chapter 10 10-11 © Prentice Hall, 2004

12. Chapter 10 10-12 © Prentice Hall, 2004 Hardware Manufacturers IBM is the leader in software sales and services Hardware manufacturers tend to focus on system software and utilities

13. Chapter 10 10-13 © Prentice Hall, 2004 Prepackaged 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).

14. Chapter 10 10-14 © 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.

15. Chapter 10 10-15 © Prentice Hall, 2004 Custom 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.

16. Chapter 10 10-16 © Prentice Hall, 2004 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

17. Chapter 10 10-17 © Prentice Hall, 2004 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

18. Chapter 10 10-18 © Prentice Hall, 2004

19. Chapter 10 10-19 © Prentice Hall, 2004 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

20. Chapter 10 10-20 © Prentice Hall, 2004 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

21. Chapter 10 10-21 © Prentice Hall, 2004 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

22. Chapter 10 10-22 © Prentice Hall, 2004 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

23. Chapter 10 10-23 © Prentice Hall, 2004

24. Chapter 10 10-24 © Prentice Hall, 2004

25. Chapter 10 10-25 © Prentice Hall, 2004 Application Server/Object Framework is the highest scoring alternative

26. Chapter 10 10-26 © Prentice Hall, 2004 3-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

27. Chapter 10 10-27 © 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.

28. Chapter 10 10-28 © Prentice Hall, 2004 Cost-benefit analysis goes through significant update and revision after selecting a design strategy.

29. Chapter 10 10-29 © Prentice Hall, 2004 Schedule estimation goes through significant update and revision after selecting a design strategy.

30. Chapter 10 10-30 © Prentice Hall, 2004 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.