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Phase 2 – Systems Analysis

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  1. Phase 2 – Systems Analysis Transition to Systems Design Chapter 6

  2. Objective • Evaluate software alternatives and development strategies. • Explain advantages and disadvantages of developing in-house software versus purchasing and customizing software. • Describe how companies use outsourcing and user applications. • List the steps in purchasing and evaluating a software package • Explain the differences between a request for proposal (RFP) and a request for quotation (RFQ).

  3. Objective • Describe the system requirements document and the presentation to management at the end of the systems analysis phase. • Explain the transition from systems analysis to systems design, and the difference between logical and physical design. • Explain the importance of prototyping and describe various prototyping methods, tools, and techniques. • Discuss the system design process. • Create and use appropriate codes during systems design and development.

  4. SOFTWARE ALTERNATIVES • DEVELOP IN-HOUSE • PURCHASE SOFTWARE PACKAGES

  5. IN HOUSE Software developed by technical staff in a company’s information systems department

  6. SOFTWARE PACKAGE • Software written by another company and available for purchase • commercial application software • available for sale by software publishers or software vendors

  7. HORIZONTAL SOFTWARE • Software package that can be used by many different types of organizations • Accounting • Invoicing • Accounts payable

  8. VERTICAL SOFTWARE • Software developed to handle requirements of IS for specific type of organization • colleges • banks • insurance companies • doctor offices

  9. Developing Your Own Software • Satisfy unique requirements • Minimize changes to business procedures and policies • meet constraints of existing system • meet constraints of existing technology • utilize new technology

  10. Buying a Software Package • Less expensive • Less time to implement • Fewer errors • Already in use in other companies • Requires fewer technical staff for development • Upgraded by vendor • ????????

  11. Customize Software Packages • Off the shelf package • vendor’s standard package • Customized package • a software package that YOU or the VENDOR modify to meet your unique specifications

  12. Customizing Software Packages • Vendor makes modifications • $$$$$ and time • YOU make modifications • time , money and technical expertise • Add on supplemental components

  13. Application Service Providers • ASP • Delivers applications, or access to applications, by charging a usage or subscription fee • Application hosting

  14. Outsourcing • Use of outside company to handle a portion of company’s IT work load • Either temporary or long-term • Advantages?? • Disadvantages?? • consulting firms • consultants • contract programmers

  15. User Applications • Typically use standard business software (Office 2000), to allow user to perform tasks

  16. User Applications • Development of entire/portion of IS by end users for a company • limited to end user department • not integral to central IS • spreadsheets, database reports • often 4th generation tools

  17. User Applications • WHY • NOT ENOUGH TIME FOR IS TO DO EVERYTHING

  18. Selecting Software Steps • Evaluate IS requirements • Identify potential software vendors • Evaluate software package alternatives • Make the purchase • Install the software package

  19. Evaluate IS Requirements • Identify key features of IS • Identify IS current volume and future growth • Specify IS external constraints • hardware and software • REQUEST FOR PROPOSAL -- RFP

  20. Identify Potential Vendor • PC, midrange, mainframe, network???? • Horizontal vs Vertical • Computer store (PC only) • Hardware manufacturers • Industry trade magazines • Relative cost for pc vs mainframe

  21. EVALUATE SOFTWARE PACKAGE ALTERNATIVES • Compare identified possible software package solutions • vendor presentations • Existing users • benchmarks • literature • evaluations in trade journals • evaluations from market research • try it yourself

  22. EVALUATE SOFTWARE ALTERNATIVES • BENCHMARK TEST • measure time it takes to process set number of transactions • compare different software results

  23. MAKE THE PURCHASE • WHAT DO YOU ACTUALLY PURCHASE?? • SOFTWARE LICENSE • right to use the software under certain terms and conditions • single computer restriction very common

  24. MAKE THE PURCHASE • network?? -- site license • leasing agreements • MAINTENCE AGREEMENT • give you the right to contact vendor for assistance

  25. INSTALL SOFTWARE • IMPLEMENTATION • Load software • Test software • Train end users • Convert data to system files

  26. HARDWARE ALTERNATIVES • Request for Quotation • Request for Bid

  27. TURNKEY SYSTEM • Complete IS that includes all hardware, systems and application software, documentation, training, installation, and support from outside vendor • Usually used in smaller companies

  28. COMPLETION OF SYSTEMS ANALYSIS • Systems Requirement Document • Formal Presentation

  29. SYSTEMS REQUIREMENTS DOCUMENT • Management Summary • IS Background • Functional Requirements • Environmental Requirements • Alternatives • Recommended Alternatives • Time and Cost Estimates • Appendices

  30. SYSTEMS REQUIREMENTS DOCUMENT • Could be lengthy!!!

  31. Presentations after Systems Analysis Phase • One of the most critical milestones in entire SDLC

  32. POSSIBLE MANAGEMENT DECISIONS • Develop in-house • Modify current system • Purchase software package • Purchase and develop in house • Perform additional systems analysis • Stop all further work

  33. CHANGE CONTROL • Process of managing and controlling the requested changes in requirements for an information system

  34. CHANGE CONTROL • Freeze the requirements • maximize chance for successful delivery of IS that satisfies requirements within projected costs and schedules • Change is inevitable

  35. Transition to Systems Design • Analysis Phase – logical or essential model • Logical design of IS defines the functions and features of system and relationships among its components • Includes the output that must be produced, the input needed, processes that must be performed • without regard to how tasks will be accomplished physically

  36. Transition to Systems Design • Design Phase – physical model • Physical design of IS is a plan for the actual implementation of the system • Built on logical design • Describes the actual processes of entering, verifying and storing data, physical layout of data files, sorting procedures, exact format of reports…

  37. PROTOTYPING • Early, rapidly developed working version of IS that exhibits the essential features of the target IS • working model

  38. Approaches to Prototyping • System prototyping – full-featured, working model of IS, ready for implementation • RAD • Design prototyping (throwaway) • Used to verify user requirements, after which the prototype is discarded • Gives us a user approved design

  39. PROTOTYPING TOOLS • Procedural vs. non-procedural tools

  40. Prototyping Tools • Data Dictionary • RDBMS • report generator • query language • screen generator • application generator • 4 GL

  41. Prototyping during Systems Analysis • given to end users to evaluate how well it satisfies their needs • working model -- changes made often • takes time to develop and evaluate • lower costs in later phases of SDLC

  42. CASE TOOLS • SOFTWARE PRODUCT THAT AUTOMATES A SPECIFIC SYSTEMS LIFE CYCLE TASK • Screen generator • Computerized data dictionary • Advantages and Disadvantages of CASE tools

  43. ALTERNATIVE GRAPHICAL TOOLS • System flowchart

  44. SYSTEMS DESIGN Look carefully at system requirements from systems analysis phase to complete system design

  45. Components of IS are interdependent • First must thoroughly understand entire logical design before beginning physical design

  46. First step of System Design • Review system requirements document from Systems Analysis phase • analyst assigned to design may not have participated in analysis • time has passed since analysis phase

  47. SYSTEM DESIGN ACTIVITIES • Need to consider IS components of data, data stores, people, procedures, hardware, software, and information interrelationships