Chapter 10 - PowerPoint PPT Presentation

slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Chapter 10 PowerPoint Presentation
play fullscreen
1 / 38
Chapter 10
112 Views
Download Presentation
eugene
Download Presentation

Chapter 10

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Chapter 10 Developing and Acquiring Information Systems “Pay attention to what works, and do that.” Tom Anderson, Co-founder of MySpace

  2. Customized Vs. Off-the-Shelf Software • Customized software • Customizability • Problem specificity • Off-the-shelf software • Packaged • No specific tailoring • Less costly • Faster to procure • Combining customized and off-the-shelf software

  3. Information Systems Development • Systems analysis and design • Process of designing, building, & maintaining info. systems • Systems analyst • Early IS development • Very unstructured • Programmer skills varied • 1990s - Evolution to IS development as “discipline” • Software engineering • Benefits • Easier to train systems analysts • Systems would be easier to maintain

  4. IS Development in Action • Structured process moving through steps • Problem decomposition • Problems broken up into simpler, smaller pieces

  5. The Role of Users in Systems Development Process • Systems users are involved in all phases of system’s development process • Mutually respectful relationship necessary • Organizational members need to understand the development activities well (SDLC) Systems development life cycle

  6. Phase 1: Systems Planning and Selection • Identify and select potential projects • Projects critical to mission, goals, and objectives • Selection process varies among organizations • Formal information systems planning process • Ad hoc process • Differential focus of projects based on selection source

  7. Evaluation Criteria for Systems Projects • Different criteria may be used to evaluate projects • Usually multiple criteria examined for each project

  8. Phase 2: Systems Analysis • Designers gain understanding of current processes

  9. Key Elements to Development of a System 3 & 4. Modeling Processes and Logic 1. Collecting Requirements 2. Modeling Data

  10. Collecting System Requirements • Most important activity • Requirements collected from: • People: Users & Managers • Business processes • Documents • System requirements collection techniques: • Interviews • Questionnaires, • Observations • Document analysis

  11. Critical Success Factors Methodology • Critical success factor (CSF) • Something that must go well to ensure success • Systems analyst interviews individuals to identify their CSFs • Organization-wide CSFs are identified

  12. Joint Application Design (JAD) • Special type of group meeting • Reduced time for requirements collection

  13. Modeling Organizational Data • Systems analysts need to understand what data will be collected • Data modeling tools • Entity-relationship diagram

  14. Modeling Organizational Processes & Logic • Data flows • Movement of data through an organization • Process Logic • The way in which data are transformed

  15. Designing Forms, Interfaces & Dialogues • Designing forms • Forms are business documents • Contain some data • Collect additional data • Designing Interfaces and Dialogues • Users interact with IS through various interfaces • Example: text-based, menu-driven • User interface standards • Mac and Windows operating systems • Graphical user interface (GUI)

  16. Designing Reports, Databases and Files • Designing reports • Reports are business documents that contain predefined data • Designing databases and files • Data modeling tools used for gaining understanding • Conceptual model —ERD • Physical data model—more detailed

  17. Phase 4: System Implementation and Operation • Transformation of design into a working information system

  18. Software Programming and Testing • Programming • Transforming the system design into a working computer system • Processing and testing should occur in parallel • Tests conducted before system completion

  19. System Conversion • Installation of the new system

  20. Documentation • Information system documentation • Details of the inner workings of the system • Written by programmers • User-related documentation • Written by professional technical writers • User and reference guides • User training and tutorials • Installation procedures and troubleshooting suggestions

  21. User Training and Support • Self-paced training and tutorials the least expensive • One-on-one training the most costly • Ongoing education may be necessary

  22. System Maintenance • Typically starts after software is installed • The largest part of system development effort occurs at this stage

  23. Types of Software Maintenance • Corrective maintenance given higher priority • Corrective maintenance most likely to occur after initial system installation

  24. Prototyping • Used for development of less structured information systems • Hard to specify • Constantly changing • Trial-and-error approach

  25. Rapid Application Development • Four-phase system development methodology • Requirements planning • User design • Construction • Move to the new system • RAD becomes radical in phase 2; intensive user involvement • System builders cycle between phases 2 and 3 until system is built

  26. Object-Oriented Analysis and Design (OOA&D) • OOA&D approach done in terms of common modules (objects). Combines: • the “what” (data) with • the “how” (operations to be performed) • Different methods used to better integrate various aspects of the system • Preexisting objects can be used or adapted

  27. Need for Alternatives to Building Systems Yourself • Building systems in-house is always an option, unless you are faced with: • Limited IS staff (too small; otherwise occupied) • IS staff has limited skill set • IS staff is overworked (too many projects; too little time) • Problems with performance of IS staff • Derailed IS departments • Staff turnover • Changing requirements • Shifts in technology • Budget constraints

  28. 1. External Acquisition • Purchasing an existing system is similar to the process of deciding which car best meets your needs • Steps in External Acquisition • Competitive bid process (find the best system for lowest possible price) • Systems planning and selection • Systems analysis • Development of a request for proposal • Proposal evaluation • Vendor selection

  29. Request for Proposal (RFP) • A report detailing system requirements sent to prospective vendors • Proposal Evaluation • An assessment of proposals received from vendors • May include system demonstrations • System benchmarking • Standardized tests to compare different proposed systems • Common system benchmarks • Response time given a specified number of users • Time to sort records • Time to retrieve a set of records • Time to produce a given record • Time to read in a set of data

  30. Vendor Selection • Usually more than one system will meet the criteria • Need to prioritize/rank the proposed systems • Best ranking system is chosen • Issues to Consider • Managing Software Licenses • Shrink-wrap and click-wrap licenses • Enterprise or volume licenses • Application Service Providers (ASP) of SaaS (Software as a Service)

  31. 2. Outsourcing • Turning over responsibility for some or all of an organization’s IS development and operations to an outside firm • Your IS solutions may be housed in their organization • Your applications may be run on their computers • They may develop systems to run on your existing computers (within your organization)

  32. Why Outsourcing? • Cost and quality concerns—higher quality /lower cost • Problems in IS performance - problems meeting acceptable standards • Supplier pressure—aggressive sales force convinces IS outsourcing • Simplifying, downsizing, and reengineering— focusing on core competencies • Financial factors—liquidation of IT assets • Organizational culture—no political ties • Internal irritants - bad relationship w/ IS dept.

  33. Managing the IS Outsourcing Relationship • Ongoing management of an outsourcing alliance needed • Strong, active CIO and staff • Clear, realistic performance measurements of the system • Multiple levels of interface between customer and outsourcer • Full-time relationship managers should be assigned

  34. 3. End-User Development • Growing sophistication of users • Future users of the system are the system’s developers • Application development may be faster • No need to rely on external entities • Benefits of End-User Development • Cost of labor (reduced by end user tools) • Long development time – Users’ needs may change • End-user development may “skip” the queue – More timely • Better at responding to changing needs • No need to wait for IS staff to make updates • Reduce work overload of IT staff – shift to end users

  35. Encouraging End-User Development • Fourth-generation development (4GL) tools have made end-user development easier • Categories of 4GLs: • Personal computer tools • Example: spreadsheets, DBMS • Query language/reporting generators • Improved searching • Graphics generators • Extracting information and presenting it in graphical format • Decision-support or modeling tools • Support for analysis of more complex, multidimensional problems • Application generators • Analysis specifications given in user-friendly language

  36. End-User Development Pitfalls

  37. Microsoft’s Surface • Technology shown on CSI Miami • Users grab data with fingers • Natural gestures • Touch • Place objects on screen to get information about them • Cell phones • MP3 players

  38. Hackers, Patches, and Reverse Engineering • Hackers • Break into computer systems to steal or manipulate data • Look for security holes • Study applications until they discover a hole • Follow other hackers’ guidelines • Reverse engineer patches • Patches • Released by software producers • Plug security holes