Systems Analysis Flashcards
What are the stages of the cycle in order
Feasibility study, investigation, analysis, documentation, testing, design, implementation, changeover, maintenance/ backup
Describe the benefits and drawbacks of the agile approach
Pros:
- Easier to add features that keep upto date
- allows for changes to be made after initial planning
Cons:
- documentation is neglected
- as the project doesn’t gave a definitive plan, the final product can be very different
Describe the benefits and drawbacks of the waterfall approach
Pros:
Requires less communication between client and developer
Cons:
-cannot go back and make changes
-very bad at reacting to changing requirements
List and explain the different types of feasibility that is including the study
Technical feasibility: will the proposed system meet its objectives? Does the technology exist?
Social feasibility:, the effects on the employees and customers of the proposed system
Legal feasibility: are there any legal constraints thet would probibit parts of the system?
Why is feasibility study important?,
It is important as it shows whether or not the proposed system is worth continuing with
What are the 4 different methods of investigation
Observation
Questionnaire
Document collection
Interviews
What are the benefits and drawbacks of observation
Benefits:
Can see what’s happening
Pics up parts of the system that isn’t immediately obvious
Drawbacks:
Time consuming
Staff feel watched so behave differently
What are the benefits and drawbacks of a questionnaire
Benefits:
Cheap for a large number of people
Drawbacks:
Not everyone will complete it
What are the benefits and drawbacks of document collection
Benefits:
Inexpensive
Drawbacks:
Files can contain sensitive information
What are the benefits and drawbacks of interviews
Benefits:
Gathers large amounts of detailed information
Drawbacks:
Time consuming to carry out
Difficult to analyse large amounts of info
Hoe can a data flow diagram help an analyst
A data flow diagram visualises the process making it more clear to the analyser
What are the four different types of symbols used in dfd
Entity (box) - a data source of destination
Process (box with curved edges) - an operation performed on the data
Data store (rectangle with one missing side) - a file
Data flow (arrow) - the data and its direction of flow
What are the details usually provided in user documentation
- step by step “getting started” guides
- installation guide
- user guide focusing on user tasks
- reference manual
- glossary
- error messages + troubleshooting guide
What are the details usually provided in technical documentation
- the data structures
- algorithm designs
- variable lists
- data dictionary
- entity relationship diagrams
- design documents
Describe alpha testing
Conducted in-house by developers, occurs before the customer agrees to accept the final program.
Describe beta testing
conducted after alpha testing and later on in the software dev cycle by a select few people who report bugs to the developers to fix
Describe end user (acceptance) testing
Where the software is tested by the intended audience
What do the designers need to create during the design stage?,
Design the data structures
Files/database structures
Algorithms
User interface designs
Design the test data to be used
What are the 4 types of changeover methods
Direct changeover
Pilot changeover
Parcel changeover
Phased conversion
Explain direct changeover
Sudden changeover in New system
Explain pilot changeover
Used by part of the organisation
Explain parallel changeover
Both old and new systems running at the same time
Explain phased changeover
Phasing in parts of the system
List the 3 types of maintenance
Perfective maintenance
Adaptive maintenance
Corrective maintenance
Describe perfective maintenance
This type of maintenance improves the current system being used
Describe adaptive maintenance
Current system being used is changed to suit certain requirements
Describe Corrective maintenance
Involves fixing errors found in the current system while being used
Advantages of direct changeover
Fan be cheaper to implement
Can be the least disruptive if implemented well
Advantages of pilot
If something goes wrong only a small part of the organisation is affected
All staff can focus on one area to solve problems
Advantages of phased changeover
Could be direct or parallel
What does the phased changeover method involve
Used with larger systems that can be broken down into individual modules that can be implemented separately at different times
What does pilot changeover involve
A department is selected in the organisation and they run the new system exile the remainder continue either the established procedures
Drawbacks of direct changeover
If the new system fails organisation will have no system which is costly and dangerous
May not work well until staff are fully used to using it
Drawbacks of pilot changeover
Slower to get new system up and running compared to other methods
Might cause problems jn the changeover period when they need to communicate with eachother and have different systems
Drawbacks of phased changeover
May be compatibility issues between the new and the existing modules
