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Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 1 Managing Information Technology 6 th Edition CHAPTER 10 METHODOLOGIES FOR CUSTOM.

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Presentation on theme: "Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 1 Managing Information Technology 6 th Edition CHAPTER 10 METHODOLOGIES FOR CUSTOM."— Presentation transcript:

1 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 1 Managing Information Technology 6 th Edition CHAPTER 10 METHODOLOGIES FOR CUSTOM SOFTWARE DEVELOPMENT

2 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 2 Methodologies for Custom Software Development Although firms are likely to purchase software packages whenever they can, the development of custom software is still highly important and in demand Different approaches to developing customized applications – Traditional Systems Development Life Cycle (SDLC) – Evolutionary Prototyping – Rapid Application Development (RAD) – Agile Development

3 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 3 SYSTEMS DEVELOPMENT LIFE CYCLE Highly structured process for developing customized applications Most often requires a lot of documentation Outputs from one step inputs to next Often referred to as the “waterfall” model Key characteristic is extensive formal reviews at the end of each major step The SDLC steps

4 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 4 SYSTEMS DEVELOPMENT LIFE CYCLE Definition Feasibility Analysis Requirements Definition Construction System Design System Building System Testing Implementation Installation Operations Maintenance The SDLC Waterfall

5 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 5 SYSTEMS DEVELOPMENT LIFE CYCLE Extensive up-front time spent determining requirements to avoid expensive changes later The SDLC steps

6 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 6 SYSTEMS DEVELOPMENT LIFE CYCLE The first phase of the SDLC is the definition phase This phase contains two steps: – Feasibility analysis – Requirements definition Definition phase

7 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 7 SYSTEMS DEVELOPMENT LIFE CYCLE Three types of feasibility are assessed 1.Technical Primary responsibility of the IS analyst Based on – Knowledge of current and emerging technological solutions – IT expertise of in-house personnel – Anticipated infrastructure needed to both develop and support the proposed system Definition phase – Feasibility analysis

8 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 8 SYSTEMS DEVELOPMENT LIFE CYCLE Three types of feasibility are assessed (cont’d) 2.Operational Primary responsibility of the business manager Entails assessing the degree to which a proposed system addresses the business issues that gave rise to the idea for a new information system Definition phase – Feasibility analysis

9 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 9 SYSTEMS DEVELOPMENT LIFE CYCLE Three types of feasibility are assessed (cont’d) 3.Economic Business managers and IS analysts work together to prepare a cost/benefit analysis IS analyst responsible for establishing the developmental costs for the project Definition phase – Feasibility analysis

10 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 10 SYSTEMS DEVELOPMENT LIFE CYCLE Deliverable is a 10-20 page document: – Executive overview and recommendations – Description of what system would do and how it would operate – Analysis of costs and benefits – Development plan Definition phase – Feasibility analysis

11 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 11 SYSTEMS DEVELOPMENT LIFE CYCLE Focuses on processes, data flows, and data interrelationships rather than a specific physical implementation Requirements are gathered by: – Interviewing individuals or groups – Reviewing documents – Observing employees doing their jobs Definition phase – Requirements Definition

12 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 12 SYSTEMS DEVELOPMENT LIFE CYCLE Deliverable is a system requirements document: – Detailed descriptions of inputs and outputs, processes used to convert input data to outputs – Formal diagrams and output layouts – Revised cost/benefit analysis – Revised plan for remainder of project Definition phase – Requirements Definition

13 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 13 SYSTEMS DEVELOPMENT LIFE CYCLE The second major phase of the SDLC is the construction phase This starts after the systems requirements document from the definition phase is approved The phase contains three steps: – System design – System building – System testing Construction phase

14 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 14 SYSTEMS DEVELOPMENT LIFE CYCLE Includes: – Deciding what hardware and software to use – Designing structure and content of databases – Defining programs and their interrelationships Good design is critical for the quality of the system Construction phase – System design

15 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 15 SYSTEMS DEVELOPMENT LIFE CYCLE Deliverable is a detailed design document: – Models, such as diagrams of system’s physical structure – Descriptions of databases – Detailed specification for each program in the system – Plan for the remaining steps of the Construction phase Construction phase – System design

16 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 16 SYSTEMS DEVELOPMENT LIFE CYCLE Includes: – Producing the computer programs – Developing or enhancing the databases and files to be used by the system – Procuring new hardware and support software Construction phase – System building

17 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 17 SYSTEMS DEVELOPMENT LIFE CYCLE Might require as much time as writing the code for the system Involves testing by IS specialists, then user testing Multiple steps: – Each module of code is tested – Modules are assembled into subsystems and tested – Subsystems are combined and entire system is integration tested Construction phase – System testing

18 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 18 SYSTEMS DEVELOPMENT LIFE CYCLE Construction phase – System testing Ensures that the system performs reliably and does what it is supposed to do in the user environment User acceptance testing Major mechanism of communication among members of the project team Documentation

19 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 19 SYSTEMS DEVELOPMENT LIFE CYCLE The final phase of the SDLC is the implementation phase The success of this phase is dependent upon business managers The three steps in this phase are: – Installation – Operations – Maintenance Implementation phase

20 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 20 SYSTEMS DEVELOPMENT LIFE CYCLE Includes: – Building files and databases – Converting relevant data from one or more old systems to the new system – Training system’s end users Implementation phase – Installation

21 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 21 SYSTEMS DEVELOPMENT LIFE CYCLE Conversion from an old system to a new system can be difficult Several transitioning strategies are commonly used to assist in this change: – Parallel: organization operates old system in parallel with new system until new system is working sufficiently – Pilot: new system is introduced to only one part of the organization first Implementation phase – Installation

22 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 22 SYSTEMS DEVELOPMENT LIFE CYCLE Transitioning strategies (cont’d) – Phased: new system is implemented one component at a time – Cutover: old system is totally abandoned as soon as the new system is implemented Implementation phase – Installation

23 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 23 SYSTEMS DEVELOPMENT LIFE CYCLE New application begins operation in “production mode” Project team is usually disbanded Requires adequate documentation – System documentation for IS specialists who operate and maintain the system – User documentation for those who use the system Implementation phase – Operations

24 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 24 SYSTEMS DEVELOPMENT LIFE CYCLE The process of making changes to a system after it has been put into production mode Reasons for maintenance – Correct errors in the system – Adapt the system to changes in the environment – Enhance or improve the system Implementation phase – Maintenance

25 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 25 SYSTEMS DEVELOPMENT LIFE CYCLE Maintenance makes up about 80% of total costs over a system’s life Implementation phase – Maintenance

26 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 26 SYSTEMS DEVELOPMENT LIFE CYCLE Problems with maintenance: – Documentation may not be updated when changes to the system are made, causing problems for future maintenance – Changes to one part of the system may have an unanticipated effect on other parts of the system (i.e., ripple effect ) – Maintenance is considered low-status work by programmers, so typically only new programmers are assigned the job Implementation phase – Maintenance

27 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 27 SYSTEMS DEVELOPMENT LIFE CYCLE Problems with maintenance (cont’d): – Maintenance may introduce new errors into the system Implementation phase – Maintenance – If resources are not available, business managers may suffer long delays before needed changes are made

28 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 28 SYSTEMS DEVELOPMENT LIFE CYCLE Usually temporary Includes personnel from IS and business units Has a project manager – Traditionally from IS – Can be from business unit – May be one from each – Responsible for success of project – delivering quality system on time and within budget The SDLC project team

29 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 29 SYSTEMS DEVELOPMENT LIFE CYCLE Critical success factors: – Manageable project size – Accurate requirements definition – Executive sponsorship Managing an SDLC project

30 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 30 SYSTEMS DEVELOPMENT LIFE CYCLE SDLC advantages and disadvantages

31 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 31 PROTOTYPING METHODOLOGY Takes advantage of fourth generation procedural languages and relational database management systems Enables creation of system (or part of system) more quickly, then revise after users have tried it Is a type of evolutionary development process Can be used as a complete alternative to the SDLC or within an SDLC process

32 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 32 PROTOTYPING METHODOLOGY Prototype examples: – Input and output screens developed for users to test as part of requirements definition – “First-of-a-series” – a completely operational prototype used as a pilot – “Selected features” – only some essential features included in prototype, more added later

33 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 33 PROTOTYPING METHODOLOGY The prototyping steps

34 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 34 PROTOTYPING METHODOLOGY Representatives from IS and user management necessary Need team members who can quickly build systems using advanced tools Requires dedicated business user roles The prototyping project team

35 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 35 PROTOTYPING METHODOLOGY Advantages: – Only basic requirements needed at front end – Used to develop systems that radically change how work is done, so users can evaluate – Allows firms to explore use of new technology – Working system available for testing more quickly – Less strong top-down commitment needed at front end – Costs and benefits can be derived after experience with initial prototype – Initial user acceptance likely higher Prototyping advantages and disadvantages

36 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 36 PROTOTYPING METHODOLOGY Disadvantages: – End prototype often lacks security and control features – May not undergo as rigorous testing – Final documentation may be less complete – More difficult to manage user expectations Prototyping advantages and disadvantages

37 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 37 PROTOTYPING METHODOLOGY Two ways in which prototyping is usually incorporated into an SDLC process: Prototyping within an SDLC process 1.Used in the Definition phase to help users define system requirements

38 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 38 PROTOTYPING METHODOLOGY Two ways in which prototyping is usually incorporated into an SDLC process: Prototyping within an SDLC process 2.Includes a pilot implementation of a working prototype

39 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 39 NEWER APPROACHES Hybrid methodology combines aspects of SDLC and prototyping Goal is to produce a system in less than a year Rapid applications development (RAD)

40 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 40 NEWER APPROACHES Advantages and disadvantages Rapid applications development (RAD)

41 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 41 NEWER APPROACHES Alternative methodology for smaller projects Objective is to deliver software with very low defect rates Based on four key values: – Simplicity – Communication – Feedback – Courage Agile methodologies

42 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 42 NEWER APPROACHES eXtreme programming (XP) – Programmers write code in pairs – Use simple design and frequent testing – Three traits characterize the program design 1.System must communicate everything you want to communicate 2.System must contain no duplicate code 3.System should have the fewest number of components as possible Agile methodologies

43 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 43 NEWER APPROACHES Scrum – Based on well-orchestrated movement between team members Similar to the coordination in a rugby scrum – Emphasizes: Independent project teams Coordination and communication between and within teams Iterative and continuous monitoring of work Highly efficient work methods Agile methodologies

44 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 44 MANAGING SOFTWARE PROJECTS USING OUTSOURCED STAFF Advantages of outsourcing: – Helps keep software development costs down – Make use of technical expertise not available in- house – Can hire capacity above baseline for current amount of development work – Frees up internal resources to work on more strategic or proprietary projects – Can often complete projects more quickly

45 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 45 MANAGING SOFTWARE PROJECTS USING OUTSOURCED STAFF Onshore outsourcing: contracting with companies within the same country or region Offshore outsourcing: contracting with companies not within the same country or region – Driven by price because labor costs are typically much lower – Risks include loss of some control, language and cultural barriers, and threats of piracy of intellectual property

46 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 46 MANAGING SOFTWARE PROJECTS USING OUTSOURCED STAFF Offshore outsourcing is a good alternative when: – System requirements well-defined and remain stable – Time is of essence and 7x24 hour availability of resources a good idea – Cost of project important

47 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 47 MANAGING SOFTWARE PROJECTS USING OUTSOURCED STAFF Guidelines for managing offsite outsourcer: – Manage expectations, not staff – Take explicit actions to integrate the offsite workers – Communicate frequently – Abandoning informal ways may result in increased rigor – Create a centralized project management office – Begin with pilot projects – Hire offshore legal expertise – Use secure and redundant communication links

48 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 48


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