(SEM VI) THEORY EXAMINATION 2024-25 SOFTWARE ENGINEERING

BCS601 – SOFTWARE ENGINEERING

Time: 3 Hours | Max Marks: 70

SECTION A – Short Answer Questions

(2 × 7 = 14 marks | Attempt ALL)
Write definition + 2–3 crisp points

a. Components of Software                                     Programs: Instructions for execution

Data: Information used by programs                      Documentation: Manuals, design documents

Procedures: Steps for installation & use

b. “Software does not wear out and is not manufactured”

Software is developed, not manufactured           It does not degrade physically like hardware

Failures occur due to changes, bugs, or environment

c. Software Risk Analysis Management

Process of identifying, analyzing, and controlling risks that may affect software quality, cost, or schedule.

d. Use Case & Common Template

Use Case: Describes interaction between actor and system.

Template Components:                           Use case name

Actor                                                          Description

Pre-conditions                                           Main flow

Alternate flow                                            Post-conditions

e. Size-Oriented Measures of Software

Based on Lines of Code (LOC)                 Measures productivity, cost, and defects per LOC

Language dependent and less accurate early

f. “Exhaustive Testing is not Possible”        Infinite input combinations

Time and cost constraints                          Hence testing is selective and risk-based

g. Software Re-engineering

Process of analyzing and modifying existing software to improve maintainability, performance, or adaptability.

SECTION B – Medium Answer Questions

(7 × 3 = 21 marks | Attempt ANY THREE)
Write definition → explanation → diagram/example

a. Software Quality Attributes & Error Index

Quality Attributes:                                    Reliability

Maintainability                                            Efficiency

Usability                                                      Portability

Error Index (EI):

EI=∑(Errors×Severity)Total ErrorsEI = \frac{\sum (Errors \times Severity)}{Total\ Errors}EI=Total Errors∑(Errors×Severity)​

Used in Statistical Quality Assurance to indicate software quality.

b. DFD & State Transition Diagram (Library Management System)

DFD (2-Level):

External entities: User, Librarian, Admin

Processes: Issue book, Return book, Authentication

Data stores: Book DB, User DB

State Diagram:

States: Available → Issued → Returned             (Diagram question – very scoring)

c. Drawbacks of LOC & Function Point (FP) Method

LOC Drawbacks:                                              Language dependent

Cannot be estimated early                                Encourages lengthy code

Function Point Method (Albrecht):               Based on inputs, outputs, files, queries

CAF adjusts FP by ±35%

FP=UFP×CAFFP = UFP \times CAFFP=UFP×CAF 

d. Testing Techniques                                         Unit Testing: Individual modules

Integration Testing: Module interaction          System Testing: Complete system behavior

Each level ensures defect detection at different stages.

e. Software Maintenance is Inevitable

Reasons:                                                             Changing user requirements

Environment changes                                        Bug fixes

Types & Cost Distribution:                             Corrective (20%)

Adaptive (25%)                                                  Perfective (50%)

Preventive (5%)

SECTION C – Attempt ANY ONE

(7 marks)

a. Spiral Model                                                  Risk-driven iterative model

Phases: Planning → Risk analysis → Development → Evaluation

Suitable for large & high-risk projects           Model Selection Criteria:

Project size                                                        Risk level

User involvement

b. Software Crisis

Occurs due to:                                                   Increased software complexity

Poor project management                                Lack of standards
Results in delay, cost overrun, low quality