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Systems analysis (Describe the purpose of a feasibility study and describe…
Systems analysis
Describe the purpose of a feasibility study and describe the processes that an analyst would carry out during a feasibility study / Explain that proposed solutions must be cost effective, developed to an agreed time scale and within an agreed budget.
A feasibility study is a preliminary investigation to decide whether a solution is possible and how it may be done.
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Activities - documentation; observations; questionnaires; interviews. Outcomes - cost effective; agreed time scale; agreed budget; technically feasible?
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Represent and interpret systems in an appropriate diagrammatic form showing the flow of data and the information processing requirements.
Represent and interpret systems in an appropriate diagrammatic form showing the flow of data and the information processing requirements
Data Flow Diagrams (DFDs) - produced by a Systems Analyst; allows us to create a graphical representation of how data travels through a system.
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Describe the various methods of changeover: direct, pilot, phased and parallel, identify the most suitable in a given situation and their relative merits
Changeover
Phased - system is replaced feature by feature. Projects split by modules. Replacing some modules of old system with a new system.
Allows users to get used to the new system; staff training done in stages' focus on one feature to resolve any problems; difficulties managed in one area can be in the next area.
Slow to get new system up and running; communication between old and new systems; if new system fails, data can be lost.
Pilot - whole system is replaced department by department. Large organisations tend to have more than one site. Pilot would test on a limited number of sites.
Whole system can be fully trialed; only part of the organisation is affected by failure; pilot staff can help train other staff; difficulties identified and managed in one area can be resolved and managed in the next area.
Slower to get new system up and running; for the department. no backup if things go wrong; communication between departments with old and new systems.
Direct - 'Big Bang' approach, sudden change to a new system. Simple but dangerous. Used if there's no old system or it is broken. All new system liable to have bugs.
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Parallel - both systems running together for a time. Used if cannot afford the system to fail for any time. Safest but the most work.
SAFEST OPTION; new system available, if required; I/O can be compared to check the new system is running correctly.
Expensive as requires additional staff to operate both systems; confusion for staff/customers having 2 systems.
When would you use each?
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Pilot - GCSE Computer Science trial (some schools); Tesco 'Scan your on shopping; trial (some stores).
Direct - anytime you want a quick changeover. Simply stop using old system one day and start using the new one the next.
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