Question 1(a) [3 marks]

Differentiate between Information and Knowledge.

Answer:

Aspect	Information	Knowledge
Definition	Raw facts and figures	Processed information with understanding
Processing	Data that is organized	Information combined with experience
Application	Can be shared easily	Requires interpretation and context

Information: Raw facts, data, and figures that can be processed
Knowledge: Understanding gained through experience and learning

Mnemonic: "Information Informs, Knowledge Knows"

Question 1(b) [4 marks]

Explain Functions of OS.

Answer:

Primary Functions of Operating System:

Function	Description
Process Management	Controls execution of programs
Memory Management	Allocates and deallocates memory
File Management	Organizes and manages files
Device Management	Controls input/output devices

Process Control: Scheduling and managing running programs
Resource Allocation: Distributing system resources efficiently
User Interface: Providing interaction between user and computer

Mnemonic: "PMFD - Process, Memory, File, Device"

Question 1(c) [7 marks]

Define Universal gate and Build Basic gate using NAND Universal gate.

Answer:

Universal Gate Definition: A logic gate that can implement any Boolean function without using any other type of gate.

NAND Gate Truth Table:

A	B	NAND Output
0	0	1
0	1	1
1	0	1
1	1	0

Basic Gates using NAND:

NOT Gate using NAND:
A ----+
      |
      NAND ---- Output (NOT A)
      |
A ----+

AND Gate using NAND:
A ----+
      |
      NAND ---- NAND ---- Output (A AND B)
      |
B ----+

OR Gate using NAND:
A ---- NAND ----+
                |
                NAND ---- Output (A OR B)
                |
B ---- NAND ----+

NOT: Single input to both NAND inputs
AND: NAND followed by NOT (another NAND)
OR: NOT both inputs, then NAND result

Mnemonic: "NAND Needs Another NAND Definitely"

Question 1(c OR) [7 marks]

Perform Following Conversion:

Answer:

Conversion Solutions:

From	To	Process	Result
(1456)₈	Base 16	8→10→16	(32E)₁₆
(1011)₂	Base 10	Binary to Decimal	(11)₁₀
(247.38)₁₀	Base 8	Integer and Fraction separately	(367.3)₈

Detailed Solutions:

(1456)₈ = (32E)₁₆
- 1×8³ + 4×8² + 5×8¹ + 6×8⁰ = 512 + 256 + 40 + 6 = (814)₁₀
- 814 ÷ 16 = 50 remainder 14(E), 50 ÷ 16 = 3 remainder 2
- Result: (32E)₁₆
(1011)₂ = (11)₁₀
- 1×2³ + 0×2² + 1×2¹ + 1×2⁰ = 8 + 0 + 2 + 1 = (11)₁₀
(247.38)₁₀ = (367.3)₈
- Integer: 247 ÷ 8 = 30 remainder 7, 30 ÷ 8 = 3 remainder 6, 3 ÷ 8 = 0 remainder 3
- Fraction: 0.38 × 8 = 3.04 (take 3)
- Result: (367.3)₈

Mnemonic: "Convert Carefully, Check Calculations"

Question 2(a) [3 marks]

List out types of Memory.

Answer:

Memory Classification:

Type	Examples	Characteristics
Primary Memory	RAM, ROM, Cache	Directly accessible by CPU
Secondary Memory	HDD, SSD, CD/DVD	Non-volatile storage
Cache Memory	L1, L2, L3	High-speed buffer memory

Volatile: Loses data when power off (RAM)
Non-volatile: Retains data without power (ROM, HDD)
Access Speed: Cache > RAM > Secondary Storage

Mnemonic: "Primary Processes, Secondary Stores"

Question 2(b) [4 marks]

Differentiate Kernel Mode Vs User Mode.

Answer:

Aspect	Kernel Mode	User Mode
Privilege Level	Full system access	Restricted access
Instructions	All instructions allowed	Limited instruction set
Memory Access	Complete memory access	Limited memory regions
System Calls	Direct hardware access	Through system calls only

Kernel Mode: Operating system runs with full privileges
User Mode: Applications run with limited privileges
Security: Mode switching prevents unauthorized access

Mnemonic: "Kernel Controls, User Consumes"

Question 2(c) [7 marks]

List out types of OS and Explain any two OS

Answer:

Types of Operating Systems:

Type	Examples	Characteristics
Batch OS	Early mainframes	No user interaction
Time-sharing OS	UNIX, Linux	Multiple users simultaneously
Real-time OS	Embedded systems	Guaranteed response time
Distributed OS	Cloud systems	Multiple connected computers
Network OS	Windows Server	Network resource management
Mobile OS	Android, iOS	Smartphone/tablet systems

Detailed Explanation:

1. Time-sharing OS (Linux):

Multi-user: Multiple users can access simultaneously
Multi-tasking: Runs multiple processes concurrently
Resource Sharing: CPU time divided among processes
Examples: UNIX, Linux, Windows

2. Real-time OS:

Deterministic: Guaranteed response within time limits
Priority-based: Critical tasks get higher priority
Applications: Medical devices, industrial control
Types: Hard real-time and Soft real-time

Mnemonic: "Time Ticks, Real-time Reacts"

Question 2(a OR) [3 marks]

Explain Architecture of Linux Operating System.

Answer:

Linux Architecture Layers:

graph LR
    A[User Applications] --> B[System Call Interface]
    B --> C[Kernel Space]
    C --> D[Process Management]
    C --> E[Memory Management]
    C --> F[File System]
    C --> G[Device Drivers]
    G --> H[Hardware Layer]

User Space: Applications and user programs
System Calls: Interface between user and kernel
Kernel: Core operating system functions

Mnemonic: "Users Use, Kernel Controls"

Question 2(b OR) [4 marks]

Explain Working of Search Engine.

Answer:

Search Engine Working Process:

Step	Process	Function
Crawling	Web spiders scan websites	Discovers web pages
Indexing	Analyzes and stores content	Creates searchable database
Ranking	Applies algorithms	Determines relevance order
Retrieval	Returns results	Displays ranked results

Working Steps:

Web Crawlers: Automated bots scan internet content
Index Database: Stores and organizes webpage information
Query Processing: Analyzes user search terms
Result Ranking: Uses algorithms to order results by relevance

Mnemonic: "Crawl, Index, Rank, Retrieve"

Question 2(c OR) [7 marks]

Difference between Open Source Software and Proprietary Software.

Answer:

Aspect	Open Source Software	Proprietary Software
Source Code	Freely available and modifiable	Closed and protected
Cost	Usually free	Requires license purchase
Support	Community-based	Vendor-provided
Customization	Fully customizable	Limited customization
Examples	Linux, Firefox, LibreOffice	Windows, MS Office, Photoshop
Security	Transparent, community-audited	Security through obscurity
Updates	Community-driven	Vendor-controlled

Key Differences:

Licensing: Open source allows redistribution and modification
Cost Model: Open source typically free vs. proprietary paid
Development: Community collaboration vs. company-controlled
Transparency: Open source code visible vs. proprietary hidden

Advantages:

Open Source: Cost-effective, customizable, secure
Proprietary: Professional support, integrated features, user-friendly

Mnemonic: "Open Opens, Proprietary Protects"

Question 3(a) [3 marks]

Give full form of the following: OSI, LLC, FTP

Answer:

Full Forms:

Abbreviation	Full Form
OSI	Open Systems Interconnection
LLC	Logical Link Control
FTP	File Transfer Protocol

OSI: Networking reference model with 7 layers
LLC: Sublayer of Data Link Layer in OSI model
FTP: Protocol for transferring files over network

Mnemonic: "Open Logic Files"

Question 3(b) [4 marks]

Give advantages and disadvantages of Twisted Pair Cable.

Answer:

Twisted Pair Cable Analysis:

Advantages	Disadvantages
Low Cost	Limited Distance
Easy Installation	Electromagnetic Interference
Flexible	Lower Bandwidth
Widely Available	Security Issues

Advantages:

Cost-effective: Cheapest networking cable option
Easy Installation: Simple to install and maintain
Flexibility: Can be bent and routed easily

Disadvantages:

Distance Limitation: Maximum 100 meters without repeater
Interference: Susceptible to electromagnetic interference
Bandwidth: Lower data transmission rates compared to fiber

Mnemonic: "Twisted is Cheap but Limited"

Question 3(c) [7 marks]

What is Modulation? Explain Analog Modulation.

Answer:

Modulation Definition: Process of varying carrier signal characteristics to transmit information over long distances.

Analog Modulation Types:

Type	Parameter Varied	Application
AM	Amplitude	Radio broadcasting
FM	Frequency	FM radio, TV sound
PM	Phase	Digital communications

Amplitude Modulation (AM):

graph LR
    A[Message Signal] --> C[Modulator]
    B[Carrier Signal] --> C
    C --> D[Modulated Signal]

Key Concepts:

Carrier Wave: High-frequency signal for transmission
Message Signal: Information to be transmitted
Modulation Index: Degree of modulation applied

Applications:

AM Radio: 530-1710 kHz frequency band
FM Radio: 88-108 MHz frequency band
Television: Various modulation techniques

Advantages:

Long Distance: Enables long-range communication
Noise Immunity: FM provides better noise resistance

Mnemonic: "Amplitude Alters, Frequency Fluctuates"

Question 3(a OR) [3 marks]

List out Network Topologies. Write Advantages and Disadvantages of Bus Topology.

Answer:

Network Topologies:

Bus Topology
Star Topology
Ring Topology
Mesh Topology
Hybrid Topology

Bus Topology Analysis:

Advantages	Disadvantages
Simple Design	Single Point of Failure
Cost-effective	Limited Cable Length
Easy to Expand	Performance Degradation

Mnemonic: "Bus is Simple but Single-failure-prone"

Question 3(b OR) [4 marks]

Differentiate Serial and Parallel Transmission.

Answer:

Aspect	Serial Transmission	Parallel Transmission
Data Path	Single communication line	Multiple lines simultaneously
Speed	Slower for short distances	Faster for short distances
Cost	Lower cost	Higher cost
Distance	Suitable for long distances	Limited to short distances

Characteristics:

Serial: Bits transmitted one after another
Parallel: Multiple bits transmitted simultaneously
Applications: Serial for networks, Parallel for internal buses

Mnemonic: "Serial Single-file, Parallel Processes"

Question 3(c OR) [7 marks]

Explain Transmission Modes.

Answer:

Transmission Modes Classification:

Mode	Direction	Examples	Applications
Simplex	One-way only	Radio, TV broadcast	Broadcasting
Half-duplex	Two-way, not simultaneous	Walkie-talkie	Turn-based communication
Full-duplex	Two-way simultaneous	Telephone	Real-time communication

Detailed Explanation:

1. Simplex Mode:

Unidirectional: Data flows in one direction only
Examples: Television broadcasting, radio transmission
Advantage: Simple implementation
Disadvantage: No feedback possible

2. Half-duplex Mode:

Bidirectional: Data can flow both ways, but not simultaneously
Examples: Walkie-talkies, CB radio
Advantage: Two-way communication with single channel
Disadvantage: Cannot send and receive simultaneously

3. Full-duplex Mode:

Simultaneous Bidirectional: Data flows both ways at same time
Examples: Telephone conversations, modern networks
Advantage: Efficient real-time communication
Disadvantage: Requires more complex implementation

Mnemonic: "Simplex Single, Half-duplex Halts, Full-duplex Flows"

Question 4(a) [3 marks]

Draw Crossover Ethernet Cable.

Answer:

Crossover Cable Wiring Diagram:

RJ-45 Connector A          RJ-45 Connector B
Pin 1: White-Orange  <---> Pin 3: White-Green
Pin 2: Orange        <---> Pin 6: Green
Pin 3: White-Green   <---> Pin 1: White-Orange
Pin 4: Blue          <---> Pin 4: Blue
Pin 5: White-Blue    <---> Pin 5: White-Blue
Pin 6: Green         <---> Pin 2: Orange
Pin 7: White-Brown   <---> Pin 7: White-Brown
Pin 8: Brown         <---> Pin 8: Brown

Key Points:

Purpose: Direct connection between similar devices
Crossed Pairs: Transmit and receive pairs are swapped
Usage: PC to PC, Switch to Switch connections

Mnemonic: "Cross Connects Computers"

Question 4(b) [4 marks]

Difference between IPv4 and IPv6.

Answer:

Feature	IPv4	IPv6
Address Size	32 bits	128 bits
Address Format	Dotted decimal	Hexadecimal colon
Address Space	4.3 billion addresses	340 undecillion addresses
Header Size	Variable (20-60 bytes)	Fixed (40 bytes)

Key Differences:

IPv4 Example: 192.168.1.1
IPv6 Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
Security: IPv6 has built-in IPSec support
NAT: IPv4 requires NAT, IPv6 eliminates need

Mnemonic: "IPv4 Four-billion, IPv6 Six-teen-times-more"

Question 4(c) [7 marks]

Draw neat and clean figure of OSI Model and write down the functionality of Physical Layer and Data Link Layer.

Answer:

OSI Model Diagram:

graph LR
    A[Application Layer - 7] --> B[Presentation Layer - 6]
    B --> C[Session Layer - 5]
    C --> D[Transport Layer - 4]
    D --> E[Network Layer - 3]
    E --> F[Data Link Layer - 2]
    F --> G[Physical Layer - 1]

Layer Functions:

Layer	Function	Examples
Physical (Layer 1)	Bit transmission over medium	Cables, hubs, repeaters
Data Link (Layer 2)	Frame delivery between adjacent nodes	Switches, MAC addresses

Physical Layer Functions:

Bit Transmission: Converts data into electrical/optical signals
Medium Specification: Defines cable types and connectors
Signal Encoding: Determines how bits are represented
Transmission Rate: Controls data speed

Data Link Layer Functions:

Frame Formation: Organizes bits into frames
Error Detection: Identifies transmission errors
Flow Control: Manages data transmission rate
MAC Addressing: Uses hardware addresses for local delivery

Mnemonic: "Physical Pushes, Data-Link Delivers"

Question 4(a OR) [3 marks]

Explain Time Division Multiplexing.

Answer:

Time Division Multiplexing (TDM):

gantt
    title TDM Time Slots
    dateFormat X
    axisFormat %L
    
    section Channel A
    Data A1 :0, 100
    Data A2 :300, 400
    
    section Channel B
    Data B1 :100, 200
    Data B2 :400, 500
    
    section Channel C
    Data C1 :200, 300
    Data C2 :500, 600

TDM Characteristics:

Time Slots: Each channel gets dedicated time period
Synchronization: All channels must be synchronized
Bandwidth Sharing: Single high-speed link shared among multiple channels

Mnemonic: "Time Takes Turns"

Question 4(b OR) [4 marks]

List out types of Networking Device and Explain any one.

Answer:

Networking Devices:

Device	Layer	Function
Hub	Physical	Signal repeater
Switch	Data Link	Frame switching
Router	Network	Packet routing
Bridge	Data Link	Network segmentation

Switch Explanation:

Function: Forwards frames based on MAC addresses
Learning: Builds MAC address table dynamically
Collision Domain: Each port creates separate collision domain
Full-duplex: Simultaneous send/receive on each port

Advantages:

Bandwidth: Full bandwidth per port
Security: Frames sent only to intended recipient
Collision: Eliminates collisions

Mnemonic: "Switch Smartly Sends"

Question 4(c OR) [7 marks]

What is Computer Network? Explain types of Computer Network.

Answer:

Computer Network Definition: Interconnected collection of autonomous computers that can communicate and share resources.

Types of Computer Networks:

Type	Coverage	Examples	Characteristics
LAN	Local area (building)	Office network	High speed, low cost
MAN	Metropolitan area (city)	City-wide network	Medium speed, moderate cost
WAN	Wide area (country/world)	Internet	Lower speed, high cost

Detailed Explanation:

1. Local Area Network (LAN):

Coverage: Single building or campus
Speed: High (100 Mbps to 10 Gbps)
Technology: Ethernet, Wi-Fi
Ownership: Single organization

2. Metropolitan Area Network (MAN):

Coverage: City or metropolitan area
Speed: Medium (10-100 Mbps)
Technology: Fiber optic, microwave
Examples: Cable TV networks

3. Wide Area Network (WAN):

Coverage: Countries or continents
Speed: Variable (depends on technology)
Technology: Satellite, leased lines
Examples: Internet, corporate networks

Network Benefits:

Resource Sharing: Files, printers, applications
Communication: Email, messaging, video conferencing
Cost Reduction: Shared resources reduce costs
Data Backup: Centralized backup systems

Mnemonic: "Local Loves, Metro Manages, Wide Wanders"

Question 5(a) [3 marks]

Explain the need for information security.

Answer:

Information Security Needs:

Threat	Impact	Protection Need
Data Theft	Financial loss	Confidentiality
Unauthorized Access	Privacy breach	Access control
System Attacks	Service disruption	Availability

Key Requirements:

Confidentiality: Protecting sensitive information from unauthorized access
Data Protection: Preventing loss or corruption of valuable data
Business Continuity: Ensuring systems remain operational

Mnemonic: "Security Secures Sensitive Systems"

Question 5(b) [4 marks]

Write advantages and disadvantages of Fiber Optic Cable.

Answer:

Advantages	Disadvantages
High Bandwidth	High Cost
Immunity to EMI	Difficult Installation
Long Distance	Fragile Nature
Secure Transmission	Specialized Equipment

Advantages:

Speed: Highest data transmission rates
Distance: Can span long distances without signal degradation
Security: Difficult to tap, providing secure communication

Disadvantages:

Cost: Expensive cable and equipment
Installation: Requires skilled technicians
Maintenance: Difficult to repair and splice

Mnemonic: "Fiber is Fast but Fragile"

Question 5(c) [7 marks]

List out types of Attack. And Explain any two web based attack.

Answer:

Types of Attacks:

Category	Attack Types	Target
Web-based	SQL Injection, XSS, CSRF	Web applications
Network	DoS, DDoS, Man-in-Middle	Network infrastructure
Malware	Virus, Trojan, Ransomware	Systems and data
Social	Phishing, Social Engineering	Human users

Web-based Attacks Explained:

1. SQL Injection:

Method: Inserting malicious SQL code into web application inputs
Impact: Unauthorized database access, data theft
Example: Entering '; DROP TABLE users;-- in login form
Prevention: Input validation, parameterized queries
Severity: Can compromise entire database

2. Cross-Site Scripting (XSS):

Method: Injecting malicious scripts into web pages
Impact: Session hijacking, cookie theft, page defacement
Types: Stored XSS, Reflected XSS, DOM-based XSS
Prevention: Input sanitization, output encoding
Target: Affects users visiting compromised websites

Attack Characteristics:

SQL Injection: Targets database through web application
XSS: Targets users through compromised web pages
Common Factor: Both exploit insufficient input validation

Prevention Measures:

Input Validation: Check all user inputs
Regular Updates: Keep software and systems updated
Security Training: Educate users about attack methods

Mnemonic: "SQL Steals, XSS eXploits Scripts"

Question 5(a OR) [3 marks]

Explain Confidentiality, Integrity and Availability.

Answer:

CIA Triad Components:

Component	Definition	Examples
Confidentiality	Information access only by authorized users	Encryption, access controls
Integrity	Data accuracy and completeness	Checksums, digital signatures
Availability	Systems accessible when needed	Redundancy, backup systems

Key Concepts:

Confidentiality: Keeps information secret from unauthorized users
Integrity: Ensures data hasn't been modified without authorization
Availability: Guarantees systems are operational when required

Mnemonic: "CIA Completely Protects Information"

Question 5(b OR) [4 marks]

Find class of following IP addresses.

Answer:

IP Address Class Identification:

IP Address	First Octet	Class	Range
192.12.44.12	192	Class C	192-223
123.77.42.213	123	Class A	1-126
190.65.22.15	190	Class B	128-191
10.0.0.11	10	Class A (Private)	1-126

Class Characteristics:

Class A: 1-126 (first bit 0), supports large networks
Class B: 128-191 (first two bits 10), medium networks
Class C: 192-223 (first three bits 110), small networks
Private IPs: 10.x.x.x, 172.16-31.x.x, 192.168.x.x

Mnemonic: "A is Awesome, B is Better, C is Compact"

Question 5(c OR) [7 marks]

Explain Cryptography.

Answer:

Cryptography Definition: Science of securing communication through encoding information so only authorized parties can access it.

Cryptography Types:

Type	Key Usage	Examples	Applications
Symmetric	Single shared key	DES, AES	Fast bulk encryption
Asymmetric	Public-private key pair	RSA, ECC	Digital signatures, key exchange
Hash Functions	One-way transformation	MD5, SHA	Data integrity, passwords

Key Concepts:

1. Symmetric Cryptography:

Single Key: Same key for encryption and decryption
Speed: Fast processing for large amounts of data
Challenge: Secure key distribution
Examples: AES-256, 3DES

2. Asymmetric Cryptography:

Key Pairs: Public key (shareable) and private key (secret)
Digital Signatures: Proves authenticity and non-repudiation
Key Exchange: Secure method to share symmetric keys
Examples: RSA, Elliptic Curve Cryptography

3. Hash Functions:

One-way: Easy to compute hash, difficult to reverse
Fixed Output: Always produces same length output
Collision Resistance: Different inputs should produce different hashes
Applications: Password storage, digital forensics

Cryptographic Process:

graph LR
    A[Plaintext] --> B[Encryption Algorithm]
    C[Key] --> B
    B --> D[Ciphertext]
    D --> E[Decryption Algorithm]
    C --> E
    E --> F[Plaintext]

Applications:

Secure Communication: HTTPS, VPN, email encryption
Data Protection: File encryption, database security
Authentication: Digital certificates, password hashing
Financial Systems: Online banking, cryptocurrency

Modern Challenges:

Quantum Computing: Threat to current encryption methods
Key Management: Secure storage and distribution of keys
Performance: Balancing security with system performance

Mnemonic: "Cryptography Creates Coded Communications"