Software Process Models Questions and Answers

Answer: D

The V-Model is an extension of the Waterfall model.

The V-Model keeps the waterfall's sequential phases but bends the testing phases up into a 'V'. Each development phase on the left has a matching test level on the right: requirements with acceptance testing, system design with system testing, architecture with integration testing, and module design with unit testing. It is also called the verification and validation model.

Agile is iterative and incremental. The spiral model is risk-driven and cyclic. RAD relies on prototyping and fast iterations. None of them is the linear base the V-Model extends.

Answer: C

The most suitable model is the Agile model.

Agile methods such as Scrum deliver working software in short iterations of a few weeks and review priorities with the customer at each one. Changes in requirements are expected and absorbed into the next iteration instead of being treated as exceptions.

The Waterfall and V-models fix requirements at the start, so a late change is expensive. The spiral model iterates, but it is driven by risk analysis and is heavier, so it suits large high-risk projects more than ones whose requirements keep changing.

Answer: B

The pairing is P-2, Q-3, R-1, S-4.

• Requirements capture involves domain analysis, understanding the problem area (P-2).
• Design produces structural and behavioural models of the system (Q-3).
• Implementation is module development and integration (R-1).
• Maintenance includes performance tuning of the running system (S-4).

The other options swap the design and requirements activities, or implementation and maintenance.

Answer: C

Feasibility analysis is done in the planning phase.

Before a project is committed to, the planning (preliminary investigation) phase studies whether it is technically possible, economically worthwhile, operationally acceptable and achievable in the time available. Its result decides whether the project goes ahead at all.

Coding, testing and maintenance come later, after the project has been approved, the requirements analysed and the system designed. Feasibility work done then would be too late to influence the decision.

Answer: B

The model that follows its phases strictly in sequence is Waterfall.

In the waterfall model, requirements, design, implementation, testing, deployment and maintenance follow one another, and each phase is completed and signed off before the next begins, like water falling down a series of steps. Going back to an earlier phase is costly.

Agile works in short iterative cycles, the spiral model loops through repeated phases with risk analysis, and prototyping builds and refines working models with users. All three are iterative rather than strictly sequential.

Answer: B

The model is the Spiral model.

Barry Boehm's spiral model passes repeatedly through four quadrants: setting objectives, identifying and resolving risks (often by building a prototype), developing and testing, and planning the next loop. It combines the systematic, step-by-step character of the waterfall model with the prototyping approach, and its distinguishing feature is risk analysis in every cycle.

Agile emphasises short iterations and customer collaboration, the V-model pairs each development stage with a testing stage, and RAD aims at rapid delivery through reusable components and prototyping, but none of them is built around risk analysis.

Answer: B

The classic life cycle model is the Waterfall Model.

Pressman calls the waterfall model the classic life cycle: a linear, sequential approach that moves through communication, planning, modelling, construction and deployment, each phase finishing before the next begins. It is the oldest software process model.

The spiral model is an evolutionary, risk-driven model that came later. UML is a modelling notation, not a process model, and PSP (Personal Software Process) is a discipline for an individual developer's work.

Answer: A

The evolutionary model is the Spiral Model.

Evolutionary models produce increasingly complete versions of the software in iterations. Boehm's spiral model is the standard example: each loop of the spiral covers planning, risk analysis, engineering and evaluation, and produces a more complete release. Pressman lists prototyping and the spiral model as the evolutionary process models.

The waterfall model is linear and sequential, not evolutionary. UML is a modelling language and PSP a personal process discipline, so neither is a software process model of this kind.

Answer: D

In the spiral model risk analysis is performed in Every iteration.

Boehm's spiral model is risk-driven. Each loop of the spiral passes through the same quadrants: determine objectives, identify and resolve risks, develop and test, and plan the next iteration. Risks are re-assessed on every circuit, which is what distinguishes the spiral from the waterfall model.

Planning, engineering and evaluation are other activities in each loop, not the place where risk is analysed, and risk analysis is not confined to a single phase.

Answer: A

They stand for Rational Unified Process and Personal Software process.

The Rational Unified Process (RUP) is the iterative process framework developed by Rational Software, organised into the inception, elaboration, construction and transition phases. The Personal Software Process (PSP), created by Watts Humphrey at the Software Engineering Institute, is a discipline that helps an individual engineer measure and improve his or her own work.

'Real-time Unified Process' and 'Project Software process' are not the names behind these acronyms.