Chapter 10: Building Information Systems Flashcards
Systems Development Life Cycle (SDLC)
Series of well-defined phases performed in sequence that serves as a framework for developing a system or project
- Each phase’s output becomes the input for the next phase
- Used to design information systems from scratch
4 Phases of Systems Development Life Cycle (SDLC)
- Planning
- Requirements gathering and analysis
- Implementation
- Maintainance
Conduct Feasibility Studies (5 dimentions)
1) Economic: Assesses a system’s costs and benefits
2) Technical: Assesses whether technology to support new system is available or feasible
3) Operational: How well the proposed solution will work in the organization
4) Scheduling: Will the new system can be completed on time
5) Legal: Will the system violate any legal issues in the country where it will be used?
Phase 1: Planning
Systems designer must define the problem the organization faces
- Examine goals and how proposed system can support goals
- Identify potential system -> conduct analysis to define problem -> conduct feasibility studies -> make go decisions
Internal users
Employees who use the system regularly
External users
Not employees but do use the system
- Ex: Customers, contractors, suppliers, and other business partners
Formation of the Task Force: Joint Application Design (JAD)
Collective activity involving users, top management, and IT professionals that centers on a structured workshop to develop an application
Feasibility Study
Measure of how beneficial or practical an information system will be to an organization
1) Economic: Assesses a system’s costs and benefits
2) Technical: Assesses whether technology to support new system is available or feasible
3) Operational: How well the proposed solution will work in the organization
4) Scheduling: Will the new system can be completed on time
5) Legal: Will the system violate any legal issues in the country where it will be used?
Phase 2: Requirements-Gathering and Analysis
Defining the problem and generating alternatives for solving it
- Information is gathered for process and data analysis
2 approaches:
1) Structured systems analysis and design (SSAD): Sequential approach that treats process and data independently
2) Object-oriented: Combines process and data analysis
Phase 3: Design
The most realistic solution that offers the highest payoff for the organization is chosen
- Details of the proposed solution are outlined
3 designs:
1) Conceptual design: Overview of the system and does not include hardware or software choices
2) Logical design: Makes conceptual design specific by indicating hardware and software
3) Physical design: Created for specific platforms
Computer-Aided Systems Engineering (CASE) Tools
Automate parts of the application development process
Prototyping
Small-scale version of the system is developed
- Illustrates system benefits and allows users to offer feedback
2 types
1) Proof-of-concept prototype: Determines a system’s technical feasibility (how tasks can be done)
2) Selling prototype: Sells the proposed system to users and management by showing some features
Phase 4: Implementation
Solution is transferred from paper to action
- Team configures the system and procures components for it
- Ex: Parallel, phased-in-phased-out, Plunge (direct cutover), pilot
Parallel Implementation
Old and new systems run simultaneously for a short time to ensure the new system works correctly
Phased-in-phased-out implementation
As each module of the new system is converted, the corresponding part of the old system is retired - Process continues until the entire system is operational
Plunge (direct cutover) implementation
Old system is stopped and the new system is implemented
Pilot implementation
Analyst introduces the system in a limited area of the organization
- Implemented in the rest of the organization in stages or all at once if the system works correctly
Project Management Tools and Techniques
- Help solve scheduling problems, plan and set goals, and highlight potential bottlenecks
- Project management software helps study cost, time, and resource impact of schedule changes
PERT (Program Evaluation Review Technique) and CPM (Critical Path Method)
Determine critical paths for the completion of a series of interrelated activities
Gantt chart
Constructed using the critical path
- Allows the systems analyst to monitor the progress of the project
- Helps detect delay in the daily operation of the project
Request for Proposal (RFP)
A written document with detailed specifications the is used to request bids for equipment, supplies, or serviced from vendors
Request for information (RFI)
An alternative to RFP that narrows the list of potential vendors by focusing on project requirements
Approaches for developing information systems
1) Insourcing: Organization’s team develop system internally
2) Self-sourcing: End users develop information systems on their own
3) Outsourcing: Organizations hire external vendors or consultants
- Crowdsourcing: Process traditionally performed by employees or contractors to a crowd through an open call
Phase 5: Maintenance
- Information system is operating
- Enhancements and modifications to the system have been developed and tested
- Hardware and software components have been added or replaced
- Performance data and information is gathered and assessed
- Feedback
- Corrective action is taken if the system’s objectives are not being met
Service-Oriented Architecture (SOA)
Philosophy software that focuses on reuse of small self-contained blocks of codes to meet software needs
Rapid Application Development (RAD)
Concentrates on user involvement and continuous interaction between users and designers
Extreme Programming (XP)
Method for developing software applications and information systems (IS) projects that are divided into smaller functions in a step by step function
- Developers cannot move to the next phase until the current phase is finished
Pair programming
Extreme Programming
Two programmers participate in one development effort at one workstation
- Each programmer performs the action that the other is not currently doing
Agile Methodology
Similar to extreme programing where there is less emphasis on team coding and more emphasis on limiting the project’s scope
- Focuses on an incremental development process and timely delivery of working software
- Sets a minimum number of requirements and turns them into a working product
