Flashcards · 0417 · Topic 7

The systems life cycle flashcards

21 cards on Topic 7, subtopics 7.1 to 7.6. Pick a subtopic or study them all.

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Name four methods of researching the current system: Observation, interviews, questionnaires and examining existing documents.
Observation vs interviews: Observation shows what really happens, but staff may behave differently when watched. Interviews give detailed answers with follow-up questions, but take time, so only a few people can be asked.
Questionnaires: advantage and disadvantage: Many people can answer quickly and the results are easy to analyse. But answers may be rushed or untruthful, the response rate may be low and no follow-up questions are possible.
What is a requirements specification?: The agreed list of what the new system must do, produced at the end of analysis, along with the inputs, outputs and processing needed.

What is produced at the design stage?: Data capture forms and screen layouts, report layouts, the file or database structure (field names, data types, lengths, key field), validation routines, verification methods, choice of hardware and software, and a test plan.
Name six validation checks: Range check, length check, type check, presence check, format check and check digit.
Validation vs verification: Validation checks that data is sensible and allowed, but not that it is correct. Verification checks that data has been copied accurately from the source, by visual checking or double data entry.

Normal, abnormal and extreme test data: Normal: valid data that should be accepted. Abnormal: invalid data that should be rejected. Extreme: the largest and smallest valid values, at the edge of the range (some mark schemes say boundary).
A field accepts ages 11 to 16. Is 17 extreme or abnormal data?: Abnormal. It is outside the range, so it should be rejected. The extreme values are 11 and 16, which should be accepted.
What is live data?: Real data whose results are already known from the old system, used to test the new system after testing with test data.
What does a test plan contain?: Each test, the data to be used, the expected result and, once run, the actual result, so the two can be compared.

Direct changeover: advantage and disadvantage: The old system stops and the new one starts at once. It is quick and cheap, but if the new system fails there is nothing to fall back on.
Parallel running: advantage and disadvantage: Both systems run side by side. It is the safest, as results can be compared and the old system is a backup, but it is the most expensive because all work is done twice.
Phased implementation vs pilot running: Phased: the new system is introduced one part at a time, so problems affect one part only, but the change takes longer. Pilot: the whole system is tried in one branch first, so failure affects only that branch.
Why would a hospital avoid direct changeover for patient records?: If the new system failed there would be no working backup, putting patient safety at risk.

Who is technical documentation for, and what does it contain?: For the people who maintain or upgrade the system. It contains the purpose of the system, hardware and software requirements, flowcharts, program listings, file structures, input and output formats, validation rules and test results.
Who is user documentation for, and what does it contain?: For the people who use the system. It contains how to log in and use the features, example screens, error messages and what to do, troubleshooting tips and FAQs.
Give two items in technical documentation but not usually in user documentation: Any two of: flowcharts, program listings, file structures, hardware requirements, validation rules.

What is checked when a new system is evaluated?: Whether it meets the requirements in the original specification, how easy it is to use, how efficient it is, user satisfaction and the appropriateness of the solution.
What evidence is used in an evaluation?: A comparison of results with the requirements specification, user feedback (e.g. questionnaires) and test results.
What happens after evaluation finds limitations?: Improvements are proposed, which can start the analysis stage of the next version, which is why the stages form a cycle.