SLR 6 - SOFTWARE DEVELOPMENT

Question 1

What are the stages of the software development lifecycle SDLC?

Answer 1

• feasibility: is the problem solvable?
• requirements: working out what the solution needs to do
• analysis and design: working out how the solution needs to do it
• implementation: coding the solution
• testing: checking it actually works
• deployment: installing it in the target environment
• evaluation: checking in with the user – is the solution complete?
• maintenance: ensuring it continues to function properly by the way of improvements, patches and updates

Question 2

What is a software development methodology?

Answer 2

the arrangement of the phases of the SDLC and how programmers move from one phase to another (both forwards and backwards)

Question 3

What are the 5 main software development methodologies?

Answer 3

• waterfall
• rapid application development (RAD)
• spiral
• agile
• extreme programming

Question 4

What is the waterfall model?

Answer 4

• derives its name from its cascading effect from one phase to another
• each phase has a well-defined start and end point with identifiable deliverables
• a slight evolution of the waterfall model allows you to move back to a previous stage as well as forwards (this reflects the fact that developers often have to rework earlier stages in light of knowledge gained as development progresses)

Question 5

Advs of the waterfall model

Answer 5

• simplicity makes it easy to manage
• everyone on the project is very clear of their responsibilities at each stage
• clear deliverables
• easy to see if a project is running to schedule
• ease of management can make it suitable for large-scale development projects, assuming they are well-understood and carry little risk

Question 6

Disadvs of the waterfall model

Answer 6

• carries a lot of risk
• user doesn’t get to see the product for the first time until the project is near its end
• misunderstanding requirements can lead to a project that isn’t easy to fix
• requirements must be very well understood so this model is not suitable for complex projects

Question 7

What is rapid application development (RAD)?

Answer 7

a methodology that involves producing successive prototypes of the software until a final version is produced and approved

Question 8

Advs of RAD

Answer 8

• requirements don’t need to be made clear from the start
• focus groups involving the user can be used to gather requirements without the need for full formal requirements document upfront
• continuous feedback from the client means that the solution is likely to have excellent usability
• good for projects where the initial requirements are not fully understood, as the iterative nature prevents development from becoming side-tracked

Question 9

Disadvs of RAD

Answer 9

• focus on usability rather than how the product works (not suited for projects where code efficiency is very important
• regular contact with client must be maintained at all times
• scales poorly for large projects with big teams

Question 10

What is the spiral model?

Answer 10

• a risk-driven development methodology
• more of a guide for development teams, allowing them to adopt elements of one or more other methodologies like waterfall or RAD
• better thought of as a process model generator, where decisions on the software development methodology are made based on the risks identified