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Systems Analysis

Transition to Systems Design. Systems Analysis. Chapter 6. Transition to Systems Design. Objectives. Evaluate software alternatives and development strategies Explain advantages and disadvantages of developing in-house software versus purchasing and customizing a software package

Melvin
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Systems Analysis

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  1. Transition to Systems Design Systems Analysis

  2. Chapter 6 Transition to Systems Design Systems Analysis and Design Fourth Edition

  3. Objectives • Evaluate software alternatives and development strategies • Explain advantages and disadvantages of developing in-house software versus purchasing and customizing a software package • Describe how companies use out-sourcing and user applications Systems Analysis and Design Fourth Edition

  4. Objectives • 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) • Describe the system requirements document and the presentation to management at the end of the systems analysis phase Systems Analysis and Design Fourth Edition

  5. Objectives • 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 Systems Analysis and Design Fourth Edition

  6. Objectives • Discuss the systems design process and provide guidelines for system design • Create and use appropriate codes during systems design and development Systems Analysis and Design Fourth Edition

  7. Chapter 6 covers the remaining tasks in the systems analysis phase Evaluation of alternative solutions Preparation of the system requirements document Presentation to management Introduction Systems Analysis and Design Fourth Edition

  8. Make or buy decision In-house software Developed by the company’s IS department Software package Purchased or leased from software publishers or vendors Horizontal application Vertical application Evaluating Software Alternatives Systems Analysis and Design Fourth Edition

  9. Developing software in-house Reasons for in-house development Satisfy unique requirements Minimize changes in business procedures and policies Meet constraints of existing systems Meet constraints of existing technology Develop internal resources and capabilities Evaluating Software Alternatives Systems Analysis and Design Fourth Edition

  10. Purchasing a software package Reasons for purchasing a software package Lower costs Less time to implement Proven reliability and performance benchmarks Less technical development staff Future upgrades provided by the vendor Other companies as resources Evaluating Software Alternatives Systems Analysis and Design Fourth Edition

  11. Customizing Software packages Purchase a basic package that can be customized to suit your needs Negotiate with software vendor to make enhancements to suit your needs Purchase the package and make your own modifications Evaluating Software Alternatives Systems Analysis and Design Fourth Edition

  12. Other software alternatives Application service providers (ASP) Outsourcing End-user applications Evaluating Software Alternatives Systems Analysis and Design Fourth Edition

  13. Application service providers Delivers applications by charging a usage or subscription fee Service provided is called application hosting Offer applications on a rental basis Evaluating Software Alternatives Systems Analysis and Design Fourth Edition

  14. Outsourcing Using outside companies to handle portion of the workload, on short-term or long-term basis Contract personnel firms Systems management or facilities management firms Evaluating Software Alternatives Systems Analysis and Design Fourth Edition

  15. End-user systems Utilizes standard business software Can offer simple, low-cost solutions Users can design their own data entry forms and reports Evaluating Software Alternatives Systems Analysis and Design Fourth Edition

  16. Selecting a software alternative Decision will affect remaining SDLC phases Systems analyst’s involvement depends on which alternative is selected Evaluating Software Alternatives Systems Analysis and Design Fourth Edition

  17. Evaluating Software Alternatives Systems Analysis and Design Fourth Edition

  18. Five step process 1. Evaluate the information system requirements 2. Identify potential software vendors 3. Evaluate software package alternatives 4. Make the purchase 5. Install the software package Steps in Evaluating and Purchasing Software Packages Systems Analysis and Design Fourth Edition

  19. Step 1: evaluate the information system requirements Identify the key features of the system Estimate volume and future growth Specify any hardware constraints Prepare a request for proposal or quotation Steps in Evaluating and Purchasing Software Packages Systems Analysis and Design Fourth Edition

  20. Step 2: identify potential software vendors Next step is to contact potential vendors An RFP will help vendors to identify solutions Various sources of information on suppliers Retailers Computer manufacturers Industry trade journals or Web sites IT consultants Newsgroups Steps in Evaluating and Purchasing Software Packages Systems Analysis and Design Fourth Edition

  21. Step 3: evaluate software package alternatives Object is to compare software packages and select the best alternative Obtain information from many sources Evaluation process Obtain information from existing users Test the application Benchmark the package if necessary Steps in Evaluating and Purchasing Software Packages Systems Analysis and Design Fourth Edition

  22. Step 4: make the purchase Software licenses Lease agreements Maintenance agreements Steps in Evaluating and Purchasing Software Packages Systems Analysis and Design Fourth Edition

  23. Step 5: install the software package Installation time depends on size and complexity Before using the package, complete all implementation steps Loading, configuring, and testing the software Training users Converting data files to new format Steps in Evaluating and Purchasing Software Packages Systems Analysis and Design Fourth Edition

  24. Evaluation and selection teams Objective of the process is to obtain the product with the lowest cost of ownership Team approach ensures that critical factors are not overlooked and that a sound choice is made Steps in Evaluating and Purchasing Software Packages Systems Analysis and Design Fourth Edition

  25. Evaluation and selection teams Primary objectives Eliminate system alternatives that will not work Rank the alternatives that will work Present the viable alternatives to management for a final decision Steps in Evaluating and Purchasing Software Packages Systems Analysis and Design Fourth Edition

  26. System requirements document Also called software requirements specification Describes alternatives and makes recommendation to management Similar to a contract for what will be delivered Must be clear and understandable to users Completion of Systems Analysis Systems Analysis and Design Fourth Edition

  27. Presentation to management Five probable management decisions 1. Develop an in-house system 2. Modify the current system 3. Purchase or customize a software package 4. Perform additional systems analysis work 5. Stop all further work Completion of Systems Analysis Systems Analysis and Design Fourth Edition

  28. Transition to Systems Design • Essential to have an accurate and understandable system requirements document • Errors, omissions, and ambiguities will affect the quality of the finished product Systems Analysis and Design Fourth Edition

  29. Transition to Systems Design • Systems design overview • Logical design defines the functions and features of the system • Also know as the essential model • Physical design is a plan for the implementation of the system Systems Analysis and Design Fourth Edition

  30. Transition to Systems Design • The relationship between analysis and design • Design phase cannot begin until analysis work is complete • Should return to the analysis phase only in very limited situations Systems Analysis and Design Fourth Edition

  31. Analysts must understand entire logical design before beginning physical design Systems design steps Review the system requirements Design the system Output Input Files and databases System architecture Present the systems design Overview of Systems Design Systems Analysis and Design Fourth Edition

  32. Systems design objectives Build a system that is: Effective Reliable Maintainable Overview of Systems Design Systems Analysis and Design Fourth Edition

  33. Systems design considerations User considerations Make the system user-friendly Consider where users receive output, or provide input to the system Anticipate future needs Users Information system Organization Must provide flexibility Overview of Systems Design Systems Analysis and Design Fourth Edition

  34. Overview of Systems Design • Systems design considerations • Data considerations • Enter data where and when it occurs • Verify data where it is input • Use automated data-entry methods • Control access for data entry • Report all entries or changes to critical values • Enter data into a system only once • Avoid data duplication Systems Analysis and Design Fourth Edition

  35. Overview of Systems Design • Systems design considerations • Processing considerations • Use a modular design • Design modules that perform a single function Systems Analysis and Design Fourth Edition

  36. Overview of Systems Design • Design tradeoffs • Design goals often conflict with each other • Easier use might create more complex programming requirements • More flexibility might increase maintenance needed • Meeting one user’s requirements might make it harder to satisfy another’s needs • A major issue is quality versus cost Systems Analysis and Design Fourth Edition

  37. Designing and Using Codes • A code is a set of letters or numbers that represents an item of data • Overview of codes • Codes serve many useful purposes • Save storage space and costs • Reduce data transmission time • Decrease data entry time • Can reveal or conceal information • Can reduce input errors Systems Analysis and Design Fourth Edition

  38. Designing and Using Codes • Types of coding • Sequence codes • Block sequence codes • Alphabetic codes • Category codes • Abbreviation codes • Mnemonic codes Systems Analysis and Design Fourth Edition

  39. Designing and Using Codes • Types of Coding • Sequence codes • Block sequence codes • Alphabetic codes • Category codes • Abbreviation codes • Mnemonic codes • Significant digit codes Systems Analysis and Design Fourth Edition

  40. Designing and Using Codes • Types of coding • Sequence codes • Block sequence codes • Alphabetic codes • Category codes • Abbreviation codes • Mnemonic codes • Significant digit codes • Derivation codes Systems Analysis and Design Fourth Edition

  41. Designing and Using Codes • Types of coding • Sequence codes • Block sequence codes • Alphabetic codes • Category codes • Abbreviation codes • Mnemonic codes • Significant digit codes • Derivation codes • Cipher codes • Action codes • Self-checking codes Systems Analysis and Design Fourth Edition

  42. Designing and Using Codes • Developing a code • Keep codes concise • Allow for expansion • Keep codes stable • Makes codes unique • Use sortable codes • Avoid confusing codes • Make codes meaningful • Use a code for a single purpose • Keep codes consistent Systems Analysis and Design Fourth Edition

  43. EndChapter 6

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