Topic 1.5 - Systems Analysis Flashcards
What are the two methodologies for systems analysis?
- Waterfall
- Agile
When would you use the waterfall methodology?
When the requirements are known, clear and fixed and the technology is understood
When would you use the agile methodology?
When the end users’ needs are ever changing in a dynamic business or when they aren’t sure what type of system they want
What are the advantages of the waterfall method?
- Criteria is documented and agreed upon
- Stages aren’t revisited
- Programmers have a clear idea of what they need to do
- Easy to manage
What are the disadvantages of the waterfall method?
- Criteria cannot be changed once it has been signed off
- Difficult to fully understand users requirements at the start of the project
- No working software is created until later in the project
What are the advantages of the agile methodology?
- Working software delivered much sooner than waterfall
- Less time spent on documenting
- Change in circumstances can be accommodated for
What are the disadvantages of the agile methodology?
- The project can be quickly taken of track if the user isn’t clear with their requirements
- Difficult to assess the difficulty and length of the project
What is the first stage in the analysis of a system?
Feasibility study
What is the purpose of a feasibility study?
To decide whether a solution is possible or to decide whether the current system can be replaced / worth replacing
- Plus, seeing if it economically possible or possible to fir within a certain timetable
What is the acronym which outlines the different aims in the feasibility study?
Seeing if its possible for the following: T - Technologically E - Economically L - Legally O - Operationally S - Schedule
What are activities in a feasibility study?
- Observing current system
- Consulting current documentation
- Storage considered
- Interviews of users
- Legal / Social / Environmental issues are considered
- Possible solutions identified
What are the outcomes of a feasibility study?
Whether the project can be completed..
- in the time scale
- within the budget
- if training is required for staff
What is the second stage in systems analysis?
The analysis stage
What are the main methods in the analysis stage?
- Interviews
- Questionnaires
- Time and motion study
- Research of similar solutions from similar businesses
- Documentation inspection
What is a DFD and what does it look like?
Data Flow Diagram
- Shows the flow of data through a system
- From external entities
- Through processes (verbs)
- And into data stores
- All data on arrows should be nouns
What is abstraction?
This is where unnecessary detail is ignored and only the important details are focused on.
What is decomposition?
This is a way of organising complex problems into more atomic ones so a problem is easier to manage
What is high level design?
High level design has three areas:
- User interface
- Logic
- Data
What are structure charts?
Similar to data flow diagrams however it shows the different functions and what parameters are passed between them
What needs to be considered when planning the new system in terms of hardware and software?
- Any off-the-shelf software needed needs to be listed
- Whether existing hardware will be compatible with the new system
- What new hardware will need to be purchased from input devices to storage such as servers
What is the third stage in the systems analysis process?
The design stage
What ‘D.D’ needs to be produced in the design stage? Give some field names
A data dictionary
- Name
- Description
- Validation
- Data type
- If the data is calculated from other data or if it’s imputed
What ‘D.S’ needs to be produced in the design stage? Give some details about this
Data structures
- Needs to be normalised
- Needs to show how data is related
- File formats
- Method of access
What designs need to be documented in the design phase?
- Form designs
- Input box designs
- Report designs
What are the different types of testing?
- Alpha
- Beta
- Acceptance testing
What is alpha testing?
This is where in house development teams test the system to find errors
What are the two types of alpha testing and what do they do?
White box - By programmers who understand the code and can test for efficiency
Black box - By developers who don’t know what the code does and they test it to see if it does what its supposed to do
What is beta testing?
This involves using a large sample of real users to get feedback on the solution. It occurs later in development and problems and automatic feedback is delivered to the development team.
What is acceptance testing?
This is the final stage in testing and it checks the following:
- Meets customer specification
- Whether any major changes are needed in operation procedures
- To test the system in the environment it is going to be run in
How is the agile method structured?
In short 30 day cycles where a working prototype is produced at the end of each
What are the different types of changeover?
Direct - All at once
Phased - Different parts of the system change at different times
Pilot - One location trials the new system first
What are the different ways of maintaining a system?
Perfective - Further improving performance and efficiency
Adaptive - Changing the system to meet the changing needs of the system
Corrective - Correcting errors not found in testing
What are the different methods in backing up data?
- Magnetic tape every evening
- DVD / Blu-Ray (Long term storage)
- Cloud storage
- Redundant Array of Inexpensive Disks (server)
