Section 7 - The systems life cycle Flashcards
What does the analysis look at?
Current problems Problem to be solved by new system What does the user want Identify inputs, processing and outputs User and information requirements of new system (what tasks it should be able to do)
What are the methods of researching an existing system?
Observation
Interviews
Questionnaires
Examination of existing documents
Observation
An analyst observes somebody using the current system
Advantages + disadvantages of observation
ads:
Can see exactly what is going well
disads:
Person might feel uncomfortable → work differently
Interviews
Face to face, talks to people at various levels of the business, detailed questions
Advantages + disadvantages of interviews
ads:
Questions can be explained
Questions can be changed to suit different people
disads:
Expensive to carry out
Takes longer
Questionnaires
Prepared questions given to users, left to compete (paper/digital)
Advantages + disadvantages of questionnaires
ads:
Questions can be answered quickly
Fairly cheap
disads:
Unclear questions cannot be explained
Incorrect data if people misunderstand
Examination of existing documents
Looking at paperwork for current system
Advantages + disadvantages of examining existing documents
ads:
Allows analyst to predict size of system needed
Can see existing inputs, processing and outputs
disads:
Time consuming
Expensive
What is ‘requirements specification’?
Systems analysts specifies a list of requirements for new system
What are ‘designs’ for?
the new system have a lot of thoughts put into them to try and reduce faults at a later stage.
What are the things that are designed?
- Data entry screens (how data can be entered in system (e.g text boxes, drop menus)
- User-interface layouts (what will things - menus, searching look like
- Printed outputs (what will printed outputs look like)
- Screen-based outputs (what will outputs on screen look like)
- Structures to store data (e.g. for databases, how table will be designed)
- Data validation methods (how will system prevent incorrect data from being entered)
- Data verification methods (How will system check data entered is correct)
What are the four stages of development?
- Creating data/file structures
- Creating validation routines
- Creating input methods (e.g. user interface)
- Creating output formats
What do validation checks/rules make sure of?
Validation checks/rules make sure that only the correct data can be entered into system
How are systems created?
System developed from lines of code (using code then creating interface)
How are data structures tested?
Entering data that should be accepted
Purposely entering data that should not be accepted
What are input methods?
A system that allows users to enter data into the system is known as data entry forms
What are two types of system outputs?
On screen
Printouts (hard copies)
How are system outputs created?
Report invoices
Pay slips
etc.
Why is it important that testing takes place?
It must be tested to make sure that it works correctly
Examples of modules that should be tested
Data structures - do tables hold data correctly?
Validation rules
Input screens
Output screens
How to test for the whole system?
Make sure that all the individual modules work with each other correctly
What is ‘normal data’?
data which should be accepted and pass the test without any problems (in this example any numbers between 1 and 5)
E.g. the numbers 1,2,3,4, or 5 should be accepted
