4/8: Systems Analysis & Development Systems change affecting organizations Systems development...
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4/8: Systems Analysis & Development
• Systems change affecting organizations
• Systems development
• Influences on & challenges to implementation
• Systems development approaches
• Systems building methodologies
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Systems development & org. change
automation
rationalization
reengineering
paradigm shift
RIS
K
RETURN
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automation
Systems development & org. change• Automation
– Using the computer to speed up the performance of existing tasks
RETURN
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Systems development & org. change
rationalization
• Rationalization– Involves streamlining of standard operating
procedures, eliminating obvious bottlenecks, so that automation makes operating procedures more efficient.
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Systems development & org. change
reengineering
• Reengineering– Radical redesign of business processes, combining &
eliminating steps to reduce waste and repetition, to improve cost, quality, and service.
– Management must understand & measure current design to assess improvements with new design.
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Systems development & org. change
paradigmshift
• Paradigm shift– Rethinking the nature of the business and the nature
of the organization itself.
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2 Ways to Find the IS Requirements• Enterprise Analysis: “looking at the whole”
– Central approach: ask large number of managers:• How they use information, where they get it• What their environments are like• What their objectives are• How they make decisions• What their data needs are
– Create logical application groups:• Groups of data elements that support related sets of
organizational processes.
– Tends to automate whatever exists, no fundamental change.
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2 Ways to Find the IS Requirements• Strategic Analysis, or CSF: Critical Success
Factors– CSFs shaped by industry, environment, and manager– Central approach: 3-4 personal interviews with top
management, identify goals and the CSFs.– Advantages
• smaller data set to analyze.• Takes into account the environment & industry.
– Disadvantages: • it’s an art form• opinions may differ on what the CSFs are• Biased toward top management
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Systems Development• All activities that produce an IS solution to an
organizational problem or opportunity.
• A structured kind of problem-solving with six distinct activities:– Systems analysis– Systems design– Programming– Testing – Conversion– Production & Maintenance
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Systems Analysis• Defining the problem
• Identifying its causes
• Specifying the solution
• Identifying the information requirements needed.
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Systems Analysis• Includes a feasibility study
– Technical feasibility• Is the proposed solution technically achievable? Is it
possible?
– Economic feasibility• Do the benefits outweigh the costs?
– Operational feasibility• Will it work in the organizational & managerial
framework?
• Do an organizational impact analysis:– How a new IS will affect org. structure, attitudes, decision-
making, and operations.
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Systems Analysis: Info Requirements• Basically: who needs what information, when,
where, and how?
• Incredibly important!
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Systems Design• Detailed how a systems will met the information
requirements as determined by the systems analysis.
• Like a blueprint of a house
• Logical design– Lays out IS components and their relationships as
they would appear TO USERS.– Shows what the proposed IS is supposed to DO.
• Physical design– Specs out the hardware, sofware, databases, etc.
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Programming & Testing• Programming: System specifications created in
the design phase are translated into program code.
• Testing: vital step, often shortchanged.– Unit testing: seeking errors in particular programs– System testing: does the whole thing work together?– Acceptance testing: evaluation by real users, review
by management.
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Conversion• Putting the new IS into production
• Parallel strategy:– run both old & new simultaneously.
• Direct cutover:– Old completely replaced by new on spec. day.
• Pilot study:– Limited implementation by small group of users.
• Phased approach:– Parts of new IS are introduced separately.
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Production & Maintenance• New IS is up and running: in production.
• At this point, changes in the IS are called “maintenance”.
• Changes made are usually to improve efficiency.
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Influences on & Challenges to Systems Implementation
• User involvement & influence
• Management support
• Level of complexity & risk
• Management of implementation
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Systems Development Approaches• Traditional systems lifecycle
• Prototyping
• Application software packages
• End-user development
• Outsourcing
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Traditional Systems Lifecycle• Variation of systems development cycle
• Oldest method for building ISes, necessary for large, complex projects.
• Steps:– Project definition– systems study– Design– Programming– Installation– Postimplementation
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Other Approaches: Prototyping• Create an experimental system rapidly and
inexpensively for end-users
• Steps:– Identify the user’s basic requirements.– Develop an initial prototype.– Use the prototype. – Revise & enhance the prototype.
• Iterative approach: repeat the process.
• Especially good for end-user interfaces.
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Other Approaches: Application Software Packages
• Buying a premade, prepackaged application software package.
• Prewritten code can often fulfill most requirements of an proposed IS.
• Customization– Can be modified to meet needs better with optional
add-ons.
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Application Software Packages: Examples
Accounts receivable; Bond & stock management; Computer-aided design (CAD) ; document imaging; E- mail; Enterprise Resource Planning (ERP); Groupware; Health care; Hotel Management; Internet telephone; Inventory control; Job costing; Library systems; Life insurance; Mailing labels; Mathematical / statistical modeling; Order processing; Payroll; Process control;Tax accounting; Web browser; Word processing
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Other Approaches: End-User Development
• End-users develop information system with little help from technical specialists using 4th Generation tools.
• Advantages:– Increased user satisfaction– Improved requirements determination– Reduced applications backlog for IS dept.
• Disadvantages:– Relatively inefficient, rarely scalable– May hamper updating systems & requirements
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Other Approaches: Outsourcing
• Contracting– Computer center operations– Telecommunications networks– Application development to external vendors
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Systems-Building Methodologies• Structured methodologies
– Structured analysis– Structured design– Structured programming
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Structured Methodologies• Techniques are step-by-step, each step building
on the last one.– Structured analysis– Structured design– Structured programming
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Structured Analysis• Widely used to define inputs, processes, and
outputs.
• Logical, graphical model of information flow
• Primary tool: Data Flow Diagram (DFD)
• Process specifications describe the transformation occurring within the lowest level of the data flow diagram. They express the logic for each process.
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Symbols for Data Flow DiagramsDATA FLOWDATA FLOW
PROCESSPROCESS
SOURCESOURCEOR SINKOR SINK
FILEFILE
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Data Flow Diagram (DFD)
GENERATE BILL
CUSTOMER
GENERATE BALANCE
GENERATE REPORT
MANAGER
PAYMENTFILE
CUSTOMERFILE
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Structured Design• A set of design rules and techniques that
promotes program clarify & simplicity.
• Reduces effort of coding, debugging, etc.
• Documented in a structure chart:– Top-down chart, showing each level of design & its
relationship to other levels.Payroll
Get valid inputs Calc. pay Write outputs
Getinputs
Validateinputs
Calc. Gross pay
Calc. Net pay
Updatemaster
Writechecks