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
