Test and Review chapter 9

1. State the differences between archive and back-up data. Answer: Archive data is a copy of data which is no longer in regular use but may need to be looked at occasionally. Back-up data is a copy of data in regular use taken in case the original is lost, damaged or destroyed.

2.State the difference between data security and data integrity. Data security is about keeping data safe. Data integrity is about the accuracy of data.

3.Tick the correct statements about verification a) Verification is when data on the computer is checked by operators to ensure that it is the same as that recorded on the source document. b) Verification is carried out by the software to reduce the amount of errors introduced to the system. c) A typical verification check is a range check A range check is a validation check x x This describes validation

4.Tick which checks are validation checks. a) Two operators check that the data is transcribed in the same way twice b) Picture check c) Batch header check d) File look up e) Visual check x x

5. What are parity checks and how do they work? A parity check ensure that individual characters have not been altered as they are transferred from one piece of hardware to another. It involves adding an extra 1 or 0 to a transmitted binary number to make the total number of 1s in the number odd. When the binary number is received at the other end it is checked for an odd number of 1s.

6. Describe the difference between on-line and off- line processing. On-line processing means we are connected to the computer that is going to process the data we wish to put onto the system Off-line means that we are working with data that will not be processed by the computer we are working on at present. Note: blue section on page 95 is wrong

7. State the main characteristics of a real time system. Small amounts of data are processed Immediate response to events Data on the system is always up to date

8. State the main characteristics of a batch- processing system. Large volumes of data are verified and validated before processing Data is sorted into the same order as the master file before processing Most records on the master file will be updated on a batch processing run (the hit rate is high)

9. What do we mean by the term “file hit rate”? The hit rate is a measure of the number of files that are accessed (changed). The more files accessed, the higher the hit rate.

10. Stages in a large scale batch processing system a)Collect together the source documents in batches and prepare a batch header. b) c)Validate the data and create a valid transaction file and list of errors. d) e)Match the sorted transactions against the master file and perform any updates necessary f)Produce a list of mismatched data and any other reports Data keyed in off-line and verified. Start processing the data Sort the transactions into the same order as the main file

11. Fact finding or systems investigation methods often used by consultants are O Q and I bservation, uestionnaires nterviews

12. Describe the contents of a feasibility report. A feasibility report contains details of costs, benefits, a preliminary analysis and possible initial solutions or designs.

13. Which comes first – Analysis or Design? Analysis

14.Tick the correct items to be included in the design specification: a) List of problems found b) Screen and report designs c) Detailed hardware and software specification d) User manual e) List of user requirements f) Data structure details g) Test strategy/Test plan h) Details of tests carried out i) Details of any processing X This is part of Analysis X This is part of Development and Testing

15.Describe what happens during the development and testing of a system. 1.Data structures are set up 2.Software is used to develop the processes in the design specification 3.Test strategy decided 4.Test data selected and expected outcomes identified 5.Results of tests documented 6.User instructions developed

16.Describe two changeover methods that may be used during conversion from the old system to the new system. 1.Direct changeover – overnight the new system is put into use and the old system becomes unavailable 2.Phased changeover – Parts of the old system are gradually replaced by parts of the new system.

17.Implementation must be planned and involves user training and two other tasks. What are they? 1.Data conversion 2.System changeover

18.State two tasks we must carry out for maintenance on computerised information systems. 1.Change or add data structures 2.Change or add new procedures

19.State in order the main stages of the systems life cycle. (there are eight in the text book but only these six in the syllabus) 1.Investigation and Analysis 2.Design 3.Development and testing 4.Implementation 5.Monitoring 6.Maintenance

20.State three characteristics of a control system 1.Input comes from the user or from sensors 2.Processing takes place e.g. a greenhouse control system comparing the temperature from its sensor with a preset level 3.Output occurs e.g.a heater switching on or an alarm beeping 4.Feedback may also occur in a closed system

21.Feedback is when some aspect of the output is used later as input. Describe two ways (not example systems) in which feedback is used in computerised information systems. 1.Feedback is used in a closed system that operates without interference from the user 2.Feedback is used when the system generates a turnaround document

22.State three tasks you must carry out when designing a data structure. 1.Choose the correct fields 2.Decide on the data type 3.Decide on default values

23.Form, screen and report designs must be well designed. State three features of a screen layout, which has a good design. 1.Consistent layout 2.Harmonious colour scheme 3.Clear, consistent pathways through the system screens Could also have 4.Clear labelling 5.Uncluttered screens

24. A printed form should include the following features a) A clear title b) Correct amount of space for each item to be written c) Multiple choice tick lists when appropriate to save writing d) Important details at the top of the form e) Fancy fonts f) Sections to split the type of data to be captured g) Lots of pictures h) Space for a signature x x