Interview Questions and Answers

Weaknesses of waterfall model are:

a) It is Inflexible
b) Accommodating changes is very hard
c) Longest tangible delivery time. The customer does not see anything but the whole product when it�s ready.
d) Unsuitable for large projects and where requirements are not clear. 

• Requirements are very clear and fixed.
• There are no ambiguous requirements.
• Ample resources with required expertise are available freely.
• The client has high confidence in the organization.
• The organization has experience of similar projects.
• The project is short.

The V-shaped SDLC model is an extension of the waterfall model.

The typical waterfall moves linearly downwards, whereas, in the V-shaped model, phases are turned upwards after the coding phase to form the V shape. It demonstrates the relationship between each phase of SDLC and its respective testing phase. Unlike the waterfall model, the V-Shape includes early test planning.

Phases in V-Shaped model:
Verification phases are on the left side of the V-shape. It consists of:

Requirements analysis: Requirements are gathered and analysis is performed to understand the problem and propose a solution.
System Design: Engineers analyze the requirements gathered and propose ways the system can be created or built from a feasibility point of view.
Architecture design: Architecture of the system is designed consisting of various modules, depicting their relationships and communication between them. 
Module design: This is a low level design where modules are designed individually and in a detailed manner.

Coding: This is at the bottom of the V-Shape model. Module design is converted into code by developers.

Validation phases are on the right side of the V-shape. It consists of:
Unit testing: Testing by analysis of the code by developers for their independent modules is done.
Integration testing: Independent modules are tested together to validate interface and expose errors in them.
System testing: The system is tested against the system specifications.
User Acceptance testing: Testing is performed by end users to validate that the requirements mentioned in requirements phase have been met by the system or not before accepting it for production. 

Strengths of V-Shaped model:

a) Simple and easy to use model.
b) Every phase has clear and fixed deliverables.
c) Higher chances of success as test planning starts early in the SDLC cycle.
d) Quickest for project where requirements are fixed and clearly defined. 

Strengths of the prototype model are:

a) Gains customer's confidence as developers and customers are in sync with each other's expectations continuously.
b) Ideal for online systems where high level of human computer interaction is involved.
c) Very flexible, as changes in requirements can be accommodated much more easily with every new review and refining.
d) Helps the developers and users both understand the system better.
e) Software built through prototyping needs minimal user training as users get trained using the prototypes on their own from the very beginning of the project.
f) Integration requirements are very well understood and deployment channels are decided at a very early stage. 

Weaknesses of the Prototype model are:

a) Focusing on the prototype can mislead developers from understanding the actual desired system.
b) End users get confused, believing the prototype to be the complete system
c) Developers might misunderstand end users objectives.
d) Developer might get too involved in prototype and deviate from the actual system that the prototype must be converted into.
e) Expensive as prototypes need a lot of effort and time. It may take a lot of work to be done for very less needed work to be achieved.

Phases in RAD:

• Business modeling: The information flow is identified between various business functions.
• Data modeling: Information gathered from business modeling is used to define data objects that are needed for the business.
• Process modeling: Data objects defined in data modeling are converted to achieve the business information flow to achieve some specific business objective. The description is identified and created for CRUD of data objects.
• Application generation: Automated tools are used to convert process models into code and the actual system.
• Testing and turnover: Test new components and all the interfaces. 

Strengths of RAD:

a) Reduced development time.
b) Increases reusability of components
c) High modularization achieves a more flexible and maintainable system
d) Quick initial reviews occur.

e) Encourages customer feedback
f) Integration from very beginning solves a lot of integration issues.
g) Business owners actively participate 

Weaknesses of RAD:

a) Depends on strong team and individual performances for identifying business requirements.
b) Only system that can be modularized can be built using RAD
c) Requires highly skilled developers/designers.
d) High dependency on modeling skills
e) Inapplicable to cheaper projects as cost of modeling and automated code generation is very high for cheaper budgeted projects to befit. 

RAD should be used when there is a need to create a system that can be modularized in 2-3 months of time. It should be used if there's high availability of designers for modeling and the budget is high enough to afford their cost along with the cost of automated code generating tools.

RAD SDLC model should be chosen only if resources with high business knowledge are available and there is a need to produce the system in a short span of time (2-3 months). 

The strengths of the incremental model are:

a) Develop high-risk business features first
b) Every increment delivers an operational product
c) Customer's confidence is high as they validate every increment and provide feedback
d) Low initial delivery cost
e) Changes in requirements can be accommodated easily.
f) More flexible than waterfall. 

The incremental model should only be used when:

• The requirements of the complete system are clearly defined and understood.
• Major requirements must be defined; however, some details can evolve with time.
• There is a need to get a product to the market early.
• New technology is being used
• Resources with needed skill sets are not available
• There are some high-risk features and goals. 

Strengths of the Spiral model:

a) Early identification of potential risk areas.
b) Customer sees a prototype very early in the SDLC.
c) Critical and risky features are built first for risk mitigation and clarifying requirements.
d) Design can evolve with iterations.
e) Feedback from users helps maintain their expectations.
f) Cost is assessed frequently, hence better planning. 

Spiral model should be used when:

a) Prototypes are expected/needed.
b) Large and high budget projects
c) When risk assessment is very critical
d) Requirements are not very clearly defined.
e) Requirements are vague and even complex
f) The organization does not have much experience with the domain.
g) Ample time is available. 

Choosing or building the right team is vital for the success of any project.

A project needs a variety of skills and qualities that are not present in any individual. However, as a workaround, a team should be built of people with a variety of skill sets to fulfill the project need.

The main advantage of choosing team members with a mix of personality types is that it provides a wider range of views towards a project or any specific action item in the project, e.g. requirements, design, development, testing or even implementation. Different views allow for a broader angle to a problem and solution minimizing the risk of missing requirements or misunderstanding them.

Some of the personality traits that are essential to any project are:

• Aggressive go getter, contrary, a calm patient and more laid back personality
• Risk taker, contrary, a cautious personality
• Strategic, contrary, analytical personality
• Lateral thinking

Different situations in a project are handled better by different personality types and hence a perfect blend/mix of personality types is essential for the project to complete successfully. 

The 4 stages of team building are:

Forming: Team members are told what is expected out of them and where do they fit in the team. The team is guided using operating guidelines, and communication within.

Storming: During this phase team members show some resistance and frustrations trying to work together. There would be jealousies and ego clashes and the team manager must act as a referee or a coach.

Norming: In this phase the team has learnt to function as a whole. Team members find their consistent ways of working and hold their ideas back to avoid problems and conflicts. The team manager guides the team to not hold themselves back by increasing responsibilities and pressures.

Performing: In this phase the team has learnt to perform their role as whole, have and resolve conflicts, take risks, make adjustments or compromises, and perform actively to face various challenges. 

Of course. There are no hard and fast requirements for a developer to implement any SDLC model for developing a software project. The ability to simplify a project into modules and ascertain the correct progression for completion is the only reason for which SDLC models and methodology was designed in the first place. You can surely work without them but the challenges will be more and there won't be any specific process to organize your work as a whole.

The Rapid Application Development (RAD) paradigm is a software development method that relies on prototyping rather than detailed design. It should be utilized when a system that can be modularized in two to three months is required. It should be employed if there is a large number of designers available for modeling and the budget allows for their costs as well as the costs of automated code generation technologies.