System and Software Development Life Cycle (SDLC) (Phases and Models) : MCQs & PYQs with Explanation

Option C

A Software Development Life Cycle (SDLC) model defines the structured process followed to develop software. It describes how software moves from the requirement stage to deployment and maintenance.
The Waterfall Model is one of the earliest and most well-known SDLC models. It follows a linear and sequential approach, where each phase must be completed before moving to the next phase.
The typical phases in the Waterfall Model are:
1.  Requirement Analysis.
2.  System Design.
3.  Implementation (Coding).
4.  Testing.
5.  Deployment.
6.  Maintenance.
Due to its rigid structure, it is not suitable for accommodating changes easily once a phase is completed.

• It is not flexible for changes.
• Any modification requires going back to the earlier stages, which is costly and time-consuming.
• It works well only when requirements are very clear and stable.

Option A

The Spiral Model is a risk-driven software development model that follows iterative cycles or loops. Each loop includes planning, risk analysis, development, and evaluation. These cycles continue throughout the life of the software.
The spiral does not stop after a fixed number of loops or after a specific phase like testing or release. Instead, it continues even after deployment for maintenance and improvements.
The model finally ends only when the software is no longer in use and is retired.

Option C

Option A

The Preliminary Investigation phase is the first step in the System Development Life Cycle (SDLC). This phase acts like a screening process to decide if a project should move forward. During this phase, the system analyst evaluates:

• New project requests.
• The purpose of the project.
• Problems in the current system.
• Whether the project is feasible.
• Whether it should be accepted, modified, or rejected.

Option D

The Spiral Model integrates the structured nature of Waterfall with the risk assessment and iterative approach of Prototyping.

Option B

The Cleanroom software engineering strategy focuses on developing software with high reliability and zero defects by using formal methods, correctness verification, and statistical quality control. It follows an Incremental Development Approach, where the system is built and delivered in small, verified increments.

Option C

A generic process framework in software engineering consists of five main framework activities, usually, Communication, Planning, Modeling, Construction, Deployment. When these activities are carried out one after another in a strict sequence, it is called a Linear Process Flow.
The linear process flow means, no overlaps, one activity must finish before the next begins, follows a straight, step-by-step path. This is very similar to the Waterfall Model.

Option D

In Software Engineering, there are four fundamental activities that guide the development and maintenance of software systems.

Option C

When developing a new system, it is often helpful to build a quick, small, and low-cost version of the actual system first. This early version is called a Prototype. 
A prototype is  working model of the system. It is created with the intention of being modified, refined, or replaced later by a full-scale, fully operational system.

Note:

In system or software development, building the full system at once can be costly and risky if requirements are unclear. To address this, a Prototype is made as an early version that may not have all features but represents essential aspects of the system.

Option C

The Waterfall Model is a linear sequential model where each phase must be finished before the next one starts.

Option D

SDLC begins with identifying user and system requirements to define the scope and objectives of the system.

Option C

In software development, system analysis involves understanding what the system must do by gathering functional and non-functional requirements from users and stakeholders. It focuses on identifying solution requirements and expectations, not on designing or implementing the system.

Option C

The Waterfall Model represents the simplest approach in software development, featuring a linear, sequential progression through distinct phases: 

1. Requirements Analysis
2. Design
3. Implementation
4. Testing
5. Deployment
6. Maintenance

Each phase must complete fully before the next begins, with no overlap or iteration, making it straightforward to understand and manage for small, well-defined projects with stable requirements.

• Prototyping involves building and refining models repeatedly.
• Iterative follows repeated cycles of development.
• Spiral is a complex model combining iteration with risk analysis.

Option D

During the System Designing phase of the System Development Life Cycle (SDLC), the database design focuses on how data will be stored, organized, and structured. This includes creating models that describe data elements, their relationships, and the final physical storage format.

However, the Input/Output Volume is not part of database design. It relates to system performance and workload analysis.

Option D

A software process model is a structured approach that defines the sequence of steps or phases to be followed for systematic software development.

The COCOMO (Constructive Cost Model) is a well-known software cost estimation model developed by Barry W. Boehm in the late 1970s. It helps predict the amount of effort, time, and resources required to complete a software development project based on software size, usually measured in lines of code (LOC).