2.2.2 Software Development

Question 1

Describe what a software development methodology is

Answer 1

A process or series of processes used in software development.

Question 2

Describe the waterfall lifecycle methodology

Answer 2

• Series of stages - Followed in order - Can go back up the order - Then needs to follow back down in order.
• Progress to the next step is not made until the previous step is completed.
• Uses formal documented stages
• Focuses on the end user at the start
• Each stage in the life cycle feeds information to the next stage

Question 3

In what scenario would it be beneficial to use the waterfall methodology?

Answer 3

• When the requirements are clear and unlikely to change
• Very reliant on getting the definition of requirements correct at the start; changes are harder to add in at a later stage. However, this forces the definition to be well-understood.

Question 4

Describe extreme programming (XP)

Answer 4

• An iterative process designed to allow development to respond to changing user requirements.
• Involves paired programming
• The end user integral throughout XP
• The focus is on good-quality code

Question 5

Describe rapid application development

Answer 5

• Use of prototypes
• No formal analysis, or design stages so requirements do not need to be stated at the start (more flexible)
• Feedback used to influence future stages
• Reduced development time due to each subtask being given strict time limits.
• The prototype is tested and feedback is obtained from users
• The results of feedback and testing are used to inform the next prototype.

Question 6

Describe the spiral model

Answer 6

• Mostly used for large-scale projects, where risk is a factor.
• Has more focus on risk management; projects may be modified or even dropped if the risk is too great. Prioritises riskiest elements first
• Has four quadrants (determine objectives, identify and manage risk, develop and test, and plan the next iteration).
• Relies on frequent client feedback to inform future development of prototypes.
• Produces functional prototypes.

Question 7

Describe the main differences between agile and waterfall

Answer 7

• Waterfall needs fixed requirements as it is hard to change - Agile does not
• Waterfall used formal stages that are followed in order - Agile does not
• Waterfall does not involve the user in the development stages - Agile does.

Question 8

Describe White Box Testing

Answer 8

• The internal structure/ design is known (to the tester)
• Requires programming knowledge
• Tests the algorithms to ensure they do what they were designed to. Does not test functionality

Question 9

Describe Black Box Testing

Answer 9

• The internal structure/ design is not known to the tester
• Requires limited/no programming knowledge
• Testing to make sure the program produces the expected outputs based on an input.
• Does not look at the code, looks only at program specification

Question 10

Describe Alpha Testing

Answer 10

Internal testing by the programmers before showing to end user

Question 11

Describe Beta Testing

Answer 11

Testing by third party/end users to ensure it meets requirements and is functional. Helps test usability.

Question 12

Three types of test data

Answer 12

Normal - Data that is correct, so should be accepted

Extreme - The minimum/maximum values of the data that could be entered for example for teenagers 13 and 19.

Invalid / Erroneous - Invalid– Correct data type, but values higher or lower than the expected range, for teenagers greater than 19. Erroneous – Incorrect data type that the program should not accept such as entering ‘Dave’ in an age field.