pertemuan – 17-18
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Pertemuan – 17-18. Matakuliah: M0304/Corporate Information System Management Tahun: 2008. M ETODOLOGI P ENGEMBANGAN S OFTWARE M ANDIRI. S YSTEMS D EVELOPMENT L IFE C YCLE M ETHODOLOGY. - PowerPoint PPT PresentationTRANSCRIPT
Pertemuan – 17-18
Matakuliah : M0304/Corporate Information System ManagementTahun : 2008
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METODOLOGI PENGEMBANGAN SOFTWARE MANDIRI
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
Systems development life cycle (SDLC) – a highly structured approach for development of new customized software applications
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGYThe SDLC Steps
Figure 17.1 The Systems Development Life Cycle
Key characteristic is extensive formal reviewsrequired at end of each major step
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGYThe SDLC Steps
Figure 17.2 Cost Breakdown for $1 Million SDLC Project
Hallmark of SDLC approach: extensive up-front time spent determining requirements to avoid expensive changes later
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGYThe SDLC Steps
SDLC:– Most often requires a lot of documentation– Outputs from one step inputs to next– Often referred to as the “waterfall” model
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGYDefinition Phase – Requirements Definition
• Focuses on logical design: processes, data flows, and data interrelationships – not specific physical implementation
• Deliverable – 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
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGYConstruction Phase
• System Design• System Building• System Testing
Figure 17.3 Characteristics of High Quality Systems
Documentation is a major mechanism of communication during development process
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGYImplementation Phase
• Installation• Operations• Maintenance
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Implementation Phase – Installation
Figure 17.4 Implementation Strategies
Parallel Strategy
Parallel Strategy
Parallel Strategy
Parallel Strategy
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Implementation Phase – Maintenance
Figure 17.5 Percent of Development Resources Devoted to Maintenance
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Implementation Phase – Maintenance
Figure 17.6 The Widening Gap BetweenOrganization’s Needs and System’s Performance
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGYThe SDLC Project Team
• 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
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGYThe SDLC Project Team
• Includes systems analysts – Have critical roles– Work closely with business managers and end users– Have problem-solving skills, knowledge of IT capabilities,
strong business understanding• Has a business sponsor and a champion
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGYManaging an SDLC Project
• Characteristics critical for success: – Manageable project size– Accurate requirements definition– Executive sponsorship
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
Figure 17.7 Costs of Error Correction by SDLC Step
Managing an SDLC Project
(Adapted from Boehm, 1976)
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGYSDLC Advantages and Disadvantages
Figure 17.8 Advantages and Disadvantages of Traditional SDLC Approach
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PROTOTYPING METHODOLOGY• Prototyping approach:
– Takes advantage of availability 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
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PROTOTYPING METHODOLOGY
• Prototyping 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– Prototyping used as a complete alternative to traditional SDLC
methodology
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PROTOTYPING METHODOLOGY• Prototyping used as a complete alternative to traditional
SDLC methodology:– Good when requirements hard to define– Good when system needed quickly – Impractical for large, complex applications
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The Prototyping Steps
Figure 17.9 The Prototyping Life Cycle
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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
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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
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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
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PROTOTYPING METHODOLOGYPrototyping within an SDLC Process
Figure 17.10 SDLC with Prototyping to Define Requirements
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PROTOTYPING METHODOLOGYPrototyping within an SDLC Process
Figure 17.11 Prototyping/Piloting Replaces SDLC Definition Phase
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NEWER APPROACHESRapid Application Development (RAD)
Figure 17.12 Four-Step RAD Cycle
• Hybrid methodology – aspects of SDLC and prototyping
• Goal is to produce a system in less than a year
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NEWER APPROACHES
Rapid Application Development (RAD)
Joint application design (JAD) – a technique in which a team of users and IS specialists engage in an intense and structured process in order to minimize the total time required for gathering information from multiple participants
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NEWER APPROACHESRapid Application Development (RAD)
Joint application design (JAD) – a technique in which a team of users and IS specialists engage in an intense and structured process in order to minimize the total time required for gathering information from multiple participants
Computer-aided software engineering (CASE) – any software tool used to automate one or more steps of a software development methodology
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NEWER APPROACHESRapid Application Development (RAD)
Figure 17.13 Types of CASE Tools
(Adapted from Valacich, George, and Hoffer, 2001)
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NEWER APPROACHESRapid Application Development (RAD)
Figure 17.14 RAD Advantages and Disadvantages
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NEWER APPROACHES
Agile Software Development Discipline
• Alternative methodology for smaller projects• Based on four key values:
– Simplicity– Communication– Feedback – Courage
• One type: Extreme Programming (XP)– Programmers write code in pairs– Use simple design and frequent testing
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MANAGING SOFTWARE PROJECTS USING OUTSOURCED STAFF
• Advantages:– Helps keep software development costs down– Uses technical expertise not available in-house– Can often complete projects more quickly
• Off-site outsourcing:– Onshore – within same country or region– Offshore – not within same country or region
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MANAGING SOFTWARE PROJECTS USING OUTSOURCED STAFF
• Offshore alternative good option 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
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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
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• Reff-Haag
Prosedure Outsource
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OUTSOURCING
• Developing strategic partnerships• Outsourcing - the delegation of specific work to
a third party for a specified length of time, at a specified cost, and at a specified level of service
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Developing Strategic Partnerships
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Developing Strategic Partnerships• IT outsourcing takes on 1 of 4 forms:
1. Purchasing existing software2. Purchasing existing software and pay the publisher to
make certain modifications3. Purchasing existing software and pay the publisher for
the right to make modifications yourself4. Outsourcing the development of an entirely new and
unique system for which no software exists
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The Outsourcing Process
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The Outsourcing Process
• Steps of the outsourcing process1. Planning2. Define project scope3. Select a target system4. Establish logical requirements
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The Outsourcing Process
5. Develop a request for proposal• Request for proposal (RFP) - a formal document that
describes in detail your logical requirements for a proposed system and invites outsourcing organizations to submit bids for its development
6. Evaluate request for proposal returns and choose a vendor
7. Test and accept solution8. Monitor and reevaluate
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The Outsourcing Process – an RFP
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Offshore Outsourcing
Offshore outsourcing - using organizations from other countries to write code and develop systems
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The Advantages of Outsourcing
• Focus on unique core competencies• Exploit the intellect of another organization• Better predict future costs• Acquire leading-edge technology• Reduce costs• Improve performance accountability
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The Disadvantages of Outsourcing
• Reduces technical know-how for future innovation• Reduces degree of control• Increases vulnerability of strategic information• Increases dependency on other organizations