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Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition.

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Presentation on theme: "Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition."— Presentation transcript:

1 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition 3 C H A P T E R INFORMATION SYSTEM DEVELOPMENT

2 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Chapter Three Information System Development Describe the motivation for a system development process in terms of the Capability Maturity Model (CMM) for quality management. Differentiate between the system life cycle and a system development methodology. Describe eight basic principles of system development. Define problems, opportunities, and directives—the triggers for systems development projects. Describe the traditional, basic phases of system development. For each phase, describe its purpose, inputs, and outputs. Describe cross life cycle activities that overlap all system development phases. Describe four basic alternative “routes” through the basic phases of system development. Describe how routes may be combined or customized for different projects. Differentiate between computer-aided systems engineering (CASE), application development environments (ADEs), and process and project management technology as automated tools for system development.

3 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Chapter Map

4 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Process of System Development A system development process is a set of activities, methods, best practices, deliverables, and automated tools that stakeholders (Chapter 1) use to develop and maintain information systems and software. (Some books use the term ‘systems development life cycle. Don’t confuse this with the waterfall development approach, which we will consider later).

5 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition The CMM Process Management Model The Capability Maturity Model (CMM) is a framework to assess the maturity level of an organization’s information system development and management processes and products. It consists of five levels of maturity as measured by a set of guidelines called the key process areas. –Level 1—Initial: System development projects follow no prescribed process. –Level 2—Repeatable: Project management processes and practices are established to track project costs, schedules, and functionality. –Level 3—Defined: A standard system development process (sometimes called a “methodology”) is purchased or developed, and integrated throughout the information systems/services unit of the organization. –Level 4—Managed: Measurable goals for quality and productivity are established. –Level 5—Optimizing: The standardized system development process is continuously monitored and improved based on measures and data analysis established in Level 4.

6 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition The CMM Process Management Model –CMM is the information technology response to the total quality management initiative. –CMM breathed new life into the importance of a system development process. –The term “process” in CMM is equivalent to the term “methodology” as popularized in systems analysis and design methods. –Most organizations pursuing the CMM are targeting Level 3, that is, consistently using a standardized process or methodology to develop all systems. –CMM Level 2 deals with project management. CMM Level 3 deals with what has come to be known as process management.

7 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Capability Maturity Model (CMM) Level 5 OPTIMIZED Level 4 MANAGED Level 3 DEFINED Level 2 REPEATABLE RISK COMPETITIVENESS Level 1 INITIAL

8 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Life Cycle versus Methodology A system life cycle divides the life of an information system into two stages, systems development and systems operation and support. A system development methodology is a very formal and precise system development process that defines (as in CMM Level 3) a set of activities, methods, best practices, deliverables, and automated tools that system developers and project managers are to use to develop and maintain information systems and software.

9 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition A System Life Cycle Conversion Obsolescence Lifetime of a System LIFE CYCLE STAGE System Development using System Development Methodology LIFE CYCLE STAGE System Operation and Support using Information Technology Note: systems development is usually only a small portion of the total system operation and support life cycle – hopefully… Discuss!

10 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Principles of System Development Get the owners and users involved. Use a problem-solving approach. Establish phases and activities. Establish standards. Justify systems as capital investments. Don’t be afraid to cancel or revise scope. Divide and conquer. Design systems for growth and change.

11 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Phases of a Representative Methodology Note the ‘phases’ or ‘activities.’ These are pretty Standard – although not exact in ALL cases. We will discuss…

12 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Overlap of System Development Phases ID 1 2 3 4 5 6 7 8 9 Project management Preliminary investigation Problem analysis Requirements analysis Decision analysis Design Construction Implementation Operations and support MayJunJulAugSepOctNovDecJan 20012002 Task Name Every project is different depending on the size, complexity, and development methodoology or route. The key point is that the phases occur in parallel. It is important that everyone not misinterpret that the phases in this chapter are sequential. Note that project and process management are illustrated as ongoing activities that lsst the durination of a project. Will talk about project and process management in next chapter.

13 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Project Identification and Initiation Problems are undesirable situations that prevent the organization from fully achieving its purpose, goals, and/or objectives. Opportunities are chances to improve the organization even in the absence of specific problems. Directives are new requirements that are imposed by management, government, or some external influence. Note that problems, opportunities, and/or directives can either be planned or unplanned.

14 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition The PIECES Problem-Solving Framework P the need to improve performance I the need to improve information (and data) E the need to improve economics, control costs, or increase profits C the need to improve control or security E the need to improve efficiency of people and processes S the need to improve service to customers, suppliers, partners, employees, etc. PIECES is a useful way to characterize all problems. Can use PIECES to analyze requirements and solutions as well.

15 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition FAST System Development Phases This is NOT the waterfall model. This slide represents ONE methodology the authors call FAST. Remaining slides in chapter come from this. There are many variations and methodologies on this slide. Note that the full ‘life cycle’ is illustrated. Development is simply partitioned into seven phases followed by operations and support Diamonds  go/no go feasibility checkpoints consistent with creeping commitment philosophy.

16 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Cross Life Cycle Activities Cross life cycle activities are activities that overlap many or all phases of the methodology. –Fact-finding –Documentation and presentation –Feasibility analysis –Process and project management

17 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition A repository is a database where system developers store all documentation, knowledge, and products for one or more information systems or projects. Sometimes we use the term ‘dictionary’ or even ‘encyclopedia.’ (Usually depends upon what the CASE tool calls its repository…) Important thing: system development documentation (knowledge) is shared via a ‘repository’ ‘as well as’ flowing between phases and people. Sharing Knowledge via a Repository

18 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Alternative Routes through a Methodology There are MANY of variations of MANY methodologies!!!! Contrary to popular marketing and consulting hype, the routes are often merely different implementations of the same basic phases already covered (usually cleverly disguised in proprietary languages and terminology). Different routes emphasize different phases, tools, and techniques. So there are many strategies / routes through traditional phases! One size ‘does not fit all’ projects!!! Here are a few: –Model-Driven Development (MDD) –Rapid Application Development (RAD) –Commercial Off-the-Shelf Software (COTS) –Maintenance and Reengineering or hybrids of the above We will look at these….

19 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Model-Driven Development Route Modeling is the act of drawing one or more graphical representations (or pictures) of a system. Modeling is a communication technique based upon the old saying, “a picture is worth a thousand words.” Model-driven development techniques emphasize the drawing of models to help visualize and analyze problems, define business requirements, and design information systems. Model- driven route is most typically associated with / based upon: –Structured systems analysis and design — process-centered –Information engineering (IE) — data-centered –Object-oriented analysis and design (OOAD) — object-centered (integration of data and process concerns) NOT Trying to teach these techniques here…Later we will look at these in the modeling chapters. But for now:

20 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Model-Driven Development (MDD) Route The model-driven approach, with the exception of OOAD) is most commonly associated with the “waterfall” approach to system development (SDLC) While often criticized for its time and effort intensity, model-driven strategies still work well with large and unstructured problem domains!!

21 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Rapid Application Development Route Rapid application development (RAD) techniques emphasize extensive user involvement in the rapid and evolutionary construction of working prototypes of a system to accelerate the system development process. RAD is based on building prototypes that evolve into finished systems (often using time boxing) –A prototype is a smaller-scale, representative or working model of the users’ requirements or a proposed design for an information system. –A time box is a nonextendable period of time, usually 60-120 days, by which a candidate system must be placed into operation. This ‘route’ is most typically associated with prototyping, JAD, and incremental or iterative approaches to system development.

22 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Rapid Application Development (RAD) Route This approach is most often used with an incremental or iterative approach to system development. Very popular for smaller and relatively structured projects in which requirements are fairly well understood from the beginning of the project. Here, see the iterative approach…. Whole model is RAD.

23 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Commercial Off-the-Shelf Software Route Commercial off-the-shelf (COTS) software is a software package or solution that is purchased to support one or more business functions and information systems. May well be the choice! COTS has become extraordinarily important to aspiring systems analysts because an ever-increasing percentage of all information systems are purchased, not built in-house. Notion of software ‘procurement’ is very important nowadays. Likely that tomorrow’s systems analysts will be as likely to participate in a software package selection and integration as they will in a traditional design and construction type project!

24 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Commercial Off-the-Shelf (COTS) Software Route Slide depicts a typical project to select a software package and then integrate that package into a business (and its other existing information systems). COTS look more complex becauase few software packages fulfill 100 percent of an organization’s requirements. Thus a COTS project does not preclude traditional analysis, design, and construction activities to supplement capabilities not provided by the chosen software package. Most require customization. (within application’s language)

25 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Hybrid: Rapid Architected Development First of three common hybrids. Combines front-end RAD with back-end MDD methods!!!! Very popular!!! Some call this RAAD – rapid architected application development.

26 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Hybrid: Multiple Implementation This too done a lot. Methodology is based entire on MDD However, multiple design/construction/ and implementation subprojects occur in parallel after decision analysis is done. Disadvantages: subprojects implemented separately and in parallel; may not work together as originally hoped. May need a full integration subproject. May be useful for large projects with enough staff to assign to multiple subjects.

27 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Hybrid: Staged Implementation This Model driven approach has the back-end phases repeated in succession to produce ‘versions’ of the final information system. Each version can be placed into operation to provide some value to the user community until the next version is released to provide incremental functionality. Used by lots of independent software vendors as their standard approach to building a software product that then improving it with subsequent versions.

28 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition Automated Tools and Technology Computer-aided systems engineering (CASE) –Older terms: upper case and lower case for tools addressing different phases of development… Application development environments (ADEs) Process and project managers

29 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition CASE Tools Computer-aided systems engineering (CASE) tools are software programs that automate or support the drawing and analysis of system models and provide for the translation of system models into application programs. –A CASE repository is a system developers’ database. It is a place where developers can store system models, detailed descriptions and specifications, and other products of system development. Synonyms include dictionary and encyclopedia. –Forward engineering requires the systems analyst to draw system models, either from scratch or from templates. The resulting models are subsequently transformed into program code. –Reverse engineering allows a CASE tool to read existing program code and transform that code into a representative system model that can be edited and refined by the systems analyst.

30 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition CASE Architecture Some CASE tools have repository on project by project basis. Others provide or integrate into a project-independent repository to promote sharing of models and specifications between projects…. Most CASE tools interface with one or more ADEs to provide for round-trip engineering that supports the full life cycle.

31 Irwin/McGraw-Hill Copyright © 2000 The McGraw-Hill Companies. All Rights reserved Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS5th Edition ADE Tools Application development environments (ADEs) are integrated software development tools that provide all the facilities necessary to develop new application software with maximum speed and quality. A common synonym is integrated development environment (IDE) –ADE facilities may include: Programming languages or interpreters Interface construction toolsMiddleware Testing toolsVersion control tools Help authoring toolsRepository links Many ADEs either interface with one or more CASE tool repositories or they provide rudimentary CASE-like modeling tools within the ADE. This allows developers to integrate RAD and MDD techniques as was demonstrated in the first hybrid route presented earlier in these slides.


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