6-1 component-based development the sdlc focuses only on the project at hand component-based...
TRANSCRIPT
6-1
COMPONENT-BASED DEVELOPMENT
The SDLC focuses only on the project at handComponent-based development (CBD) – focuses
on building small self-contained blocks of code (components) that can be reused across a variety of applications
CBD focuses on1. Using already-developed components to build
systems quickly
2. Building new components as needed that can be used in all future systems
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Component-Based Development Methodologies
Rapid application development (RAD)Extreme programming (XP)Agile methodology
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Rapid Application Development (RAD)
Rapid application development (RAD) (also called rapid prototyping) - emphasizes extensive user involvement in the rapid and evolutionary construction of working prototypes of a system to accelerate the systems development process
Prototypes are models of the software componentsThe development team continually designs,
develops, and tests the component prototypes until they are finished
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Rapid Application Development (RAD)
Build new software
components
Use already-existing software
components
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Extreme Programming (XP)
Extreme programming (XP) - breaks a project into tiny phases and developers cannot continue on to the next phase until the first phase is complete
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Agile Methodology
Agile methodology - a form of XP, aims for customer satisfaction through early and continuous delivery of useful software components
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SoA – An Architecture Perspective
Service-oriented architecture (SoA) – perspective that focuses on the development, use, and reuse of small self-contained blocks of code (called services) to meet all application software needs
All CBD methodologies adhere to an SoAServices are the same as components, which are
the same as small self-contained blocks of codeMore in Chapter 7
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SELFSOURCING
Selfsourcing (end-user development) – the development and support of IT systems by end users with little or no help from IT specialists
Do-it-yourself systems development approach Can relieve IT specialists of the burden of
developing many smaller systems
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Selfsourcing Approach
Is similar to traditional SDLCBig exception is that design, development, testing,
and implementation are replaced by the process of prototyping
Prototyping is the process of building models, and – in this case – continually refining those models until they become the final system
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Selfsourcing Approach
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Selfsourcing Advantages
Improves requirements determinationIncreases end user participation and sense of
ownershipIncreases speed of systems developmentReduces invisible backlog
Invisible backlog – list of all systems that an organization needs to develop but – because of the prioritization of systems development needs – never get funded because of the lack of organizational resources
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Selfsourcing Disadvantages
Inadequate end user expertise leads to inadequately developed systems
Lack of organizational focus creates “privatized” IT systems
Insufficient analysis of design alternatives leads to subpar IT systems
Lack of documentation and external support leads to short-lived systems
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The Right Tool for the Job
End users must have development tools that:Are easy to useSupport multiple platformsOffer low cost of ownershipSupport a wide range of data types
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PROTOTYPING
Prototype – a model of a proposed product, service, or system
Prototyping - the process of building a model that demonstrates the features of a proposed product, service, or system Proof-of-concept prototype - used to prove the
technical feasibility of a proposed systemSelling prototype - used to convince people of the
worth of a proposed system
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The Prototyping Process
The prototyping process involves four steps:1. Identify basic requirements
2. Develop initial prototype
3. User review
4. Revise and enhance the prototype
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The Prototyping Process
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Advantages of Prototyping
Encourages active user participation Helps resolve discrepancies among usersGives users a feel for the final systemHelps determine technical feasibility Helps sell the idea of a proposed system
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Disadvantages of Prototyping
Leads people to believe the final system will followGives no indication of performance under
operational conditionsLeads the project team to forgo proper testing and
documentation
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OUTSOURCING
Outsourcing – the delegation of specified work to a third party for a specified length of time, at a specified cost, and at a specified level of service
The third “who” option of systems development, after insourcing and selfsourcing
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OUTSOURCING
The main reasons behind the rapid growth of the outsourcing industry include the following: GlobalizationThe Internet Growing economy and low unemployment rateTechnology Deregulation
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Outsourcing Options
IT outsourcing for software development can take one of four forms:
1. Purchase existing software
2. Purchase existing software and pay the publisher to make certain modifications
3. Purchase existing software and pay the publisher for the right to make modifications yourself
4. Outsource the development of an entirely new and unique system for which no software exists
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Outsourcing Options
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Outsourcing Process
Like selfsourcing, the selfsourcing process looks similar to the traditional SDLC
Big exception here is that you “outsource” most of the work to another company
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Outsourcing Process
When outsourcing, you’ll develop two vitally important documents – a request for proposal and a service level
agreement
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Outsourcing Options
There are three different forms of outsourcing:1. Onshore outsourcing - the process of engaging
another company within the same country for services
2. Nearshore outsourcing - contracting an outsourcing arrangement with a company in a nearby country
3. Offshore outsourcing - contracting with a company that is geographically far away
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The Advantages and Disadvantages of Outsourcing
Advantages:Focus on unique core competenciesExploit the intellect of another organizationBetter predict future costsAcquire leading-edge technologyReduce costsImprove performance accountability
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The Advantages and Disadvantages of Outsourcing
Disadvantages:Reduces technical know-how for future innovationReduces degree of controlIncreases vulnerability of your strategic informationIncreases dependency on other organizations