Introduction to IT Systems (4311602) - Winter 2023 Solution

Question 1(a) [3 marks]

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Differentiate between Information and Knowledge.

Answer:

• 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]

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Explain Functions of OS.

Answer:

Primary Functions of Operating System:

• 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]

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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:

Basic Gates using 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]

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Perform Following Conversion:

Answer:

Conversion Solutions:

Detailed Solutions:

1. (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

2. (1011)₂ = (11)₁₀

   • 1×2³ + 0×2² + 1×2¹ + 1×2⁰ = 8 + 0 + 2 + 1 = (11)₁₀

3. (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]

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List out types of Memory.

Answer:

Memory Classification:

• 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]

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Differentiate Kernel Mode Vs User Mode.

Answer:

• 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]

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List out types of OS and Explain any two OS

Answer:

Types of Operating 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]

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Explain Architecture of Linux Operating System.

Answer:

Linux Architecture Layers:

graph TD
    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]

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Explain Working of Search Engine.

Answer:

Search Engine Working Process:

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]

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Difference between Open Source Software and Proprietary Software.

Answer:

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]

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

Answer:

Full Forms:

• 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]

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Give advantages and disadvantages of Twisted Pair Cable.

Answer:

Twisted Pair Cable Analysis:

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]

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What is Modulation? Explain Analog Modulation.

Answer:

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

Analog Modulation Types:

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]

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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:

Mnemonic: “Bus is Simple but Single-failure-prone”

Question 3(b OR) [4 marks]

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Differentiate Serial and Parallel Transmission.

Answer:

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]

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Explain Transmission Modes.

Answer:

Transmission Modes Classification:

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]

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Draw Crossover Ethernet Cable.

Answer:

Crossover Cable Wiring Diagram:

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]

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Difference between IPv4 and IPv6.

Answer:

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]

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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 TD
    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:

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]

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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]

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List out types of Networking Device and Explain any one.

Answer:

Networking Devices:

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]

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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:

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]

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Explain the need for information security.

Answer:

Information Security Needs:

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]

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Write advantages and disadvantages of Fiber Optic Cable.

Answer:

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]

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

Answer:

Types of Attacks:

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]

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Explain Confidentiality, Integrity and Availability.

Answer:

CIA Triad Components:

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]

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Find class of following IP addresses.

Answer:

IP Address Class Identification:

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]

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Explain Cryptography.

Answer:

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

Cryptography Types:

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”