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Computer Science IX · 2024 · E-Marking Notes (Questions & Solved Better Responses)

AGA KHAN UNIVERSITY EXAMINATION BOARD
Notes from E-Marking Centre on SSC-I Computer Science Annual Examinations 2024
Digital Edition: Questions, Marking Schemes & Solved Better Responses (2025 Syllabus Aligned)
Q.1Constructed Response Questions (CRQs)
2025 Syllabus Outcome (1.5.2): explain the following types of system software: a. operating system, b. device drivers, c. utility programs, d. language processors;
Question Text
Describe the purpose of file management system in an operating system. (4 Marks)
Checking Hints (Marking Scheme • 4 Marks)
  • 1 mark for each valid function/purpose of the file management system in an operating system (FOUR required, 4 × 1 = 4 Marks).
  • Accept: directory/folder hierarchy organisation, file operations (create/rename/move/delete), mapping logical files to physical disk blocks, enforcing access permissions/security, and tracking metadata.
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (4/4)
The File Management System in an operating system organises, stores, retrieves, and protects files and folders on secondary storage devices (such as HDDs, SSDs, and USB drives). Its core responsibilities include:
1.File & Directory Organisation: Creating, naming, renaming, moving, copying, and deleting files and hierarchical folders/directories so data is logically structured.
2.Storage Space Allocation: Tracking free and allocated disk blocks/sectors and mapping logical file names to physical storage addresses.
3.Access Control & Security: Enforcing read, write, and execute permissions (via Access Control Lists) so unauthorised users cannot modify or view restricted files.
4.Backup, Recovery & Metadata Tracking: Maintaining file metadata (file size, type/extension, creation/modification timestamps) and supporting file recovery and integrity checks.
Q.2Constructed Response Questions (CRQs)
2025 Syllabus Outcome (1.8.1): explain the following communication devices: a. hub, b. modem, c. switch, d. router, e. gateway;
Question Text
Describe the role of network communication devices in enabling efficient communication and collaboration in a modern workplace. (2 Marks)
Checking Hints (Marking Scheme • 2 Marks)
  • 1 mark for explaining how network communication devices (switches, routers, modems, NICs) interconnect workstations and route data packets across local/external networks.
  • 1 mark for explaining how they enable real-time workplace communication and resource sharing (shared servers, printers, video calls, collaborative file access).
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (2/2)
Network communication devices (such as NICs, Switches, Routers, Modems, and Wireless Access Points) play two essential roles in a modern workplace:
1.High-Speed Interconnectivity & Data Routing: Devices like switches and routers direct data packets accurately between workplace computers and external networks/the Internet, enabling real-time email, instant messaging, and video conferencing without collisions or delays.
2.Centralised Resource & File Sharing: They allow multiple employees to simultaneously share central file servers, cloud workspaces, printers, and scanners, supporting seamless team collaboration across departments.
Q.3Constructed Response Questions (CRQs)
2025 Syllabus Outcome (1.9.4): explain the following network topologies emphasising their structure, functionality, advantages, and disadvantages: a. bus topology, b. ring topology, c. tree topology, d. star topology, e. mesh topology;
Question Text
i.Draw the diagram of bus topology. (1 Mark)
ii.Give ONE advantage of using bus topology. (1 Mark)
Checking Hints (Marking Scheme • 2 Marks)
  • Part i: 1 mark for drawing a valid diagram of Bus Topology showing a central shared backbone cable with multiple connected nodes and terminators.
  • Part ii: 1 mark for any ONE valid advantage of Bus Topology (e.g., low cabling cost, simple installation, easy to add a node).
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (2/2)
i. Diagram of Bus Topology (1 Mark):
Architecture / Topology Diagram
   [Node 1]         [Node 2]         [Node 3]
      |                |                |
[Terminator]====================================[Terminator]
      |        Shared Backbone Cable    |
   [Node 4]                          [Node 5]
(A single central backbone cable with terminators at both ends and multiple computer nodes connected via drop lines/taps.)
ii. ONE Advantage of Bus Topology (1 Mark):
•Cost-Effective & Less Cabling: It requires the least amount of cable compared to star or mesh topologies because all nodes share a single common backbone cable.
•(Alternative valid point) Easy to Install & Extend: New nodes can be easily connected to the shared backbone without disrupting existing workstations.
Q.4Constructed Response Questions (CRQs)
2025 Syllabus Outcome (3.4.1): write HTML code to create: a. ordered list, b. unordered list, c. definition list;
Question Text
Consider the given image of a webpage (ordered list.html displaying the heading List of dairy products followed by a numbered list 1. Milk, 2. Yogurt, 3. Butter).
Write the HTML code to display the web page shown in the given image. (5 Marks)
Diagram for Q.4
Checking Hints (Marking Scheme • 5 Marks)
  • 1 mark for <html>...</html> and <body>...</body> structure.
  • 1 mark for <head><title>ordered list.html</title></head>.
  • 1 mark for heading tag <h1>List of dairy products</h1> (accept <h1>–<h3>).
  • 1 mark for <ol>...</ol> ordered list container tags.
  • 1 mark for <li>Milk</li>, <li>Yogurt</li>, and <li>Butter</li> inside the ordered list.
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (5/5)
HTMLSource Code
<!DOCTYPE html>
<html>
<head>
    <title>ordered list.html</title>
</head>
<body>
    <h1>List of dairy products</h1>
    <ol>
        <li>Milk</li>
        <li>Yogurt</li>
        <li>Butter</li>
    </ol>
</body>
</html>
Q.5aExtended Response Questions (ERQs)
2025 Syllabus Outcome (1.2.1): define various input and output devices, including keyboards, touchscreen, pointing devices, biometric scanners, sensors, recognition systems, audio devices, display screens, printers, plotters, cutters, and actuators;
Question Text
You have recently been hired as a consultant by an advertising agency to recommend the best type of monitors for their new office. They are considering LED monitors and want to understand the advantages and disadvantages before making a decision.
Explain THREE advantages and THREE disadvantages of using LED monitors to the agency. (6 Marks)
Checking Hints (Marking Scheme • 6 Marks)
  • 1 mark for each explained advantage of LED monitors (THREE required = 3 Marks): high colour accuracy/contrast, low power consumption, slim/lightweight build, long lifespan.
  • 1 mark for each explained disadvantage of LED monitors (THREE required = 3 Marks): higher initial purchase cost, blue-light eye strain on prolonged use, viewing angle contrast/colour shift.
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (6/6)
Part a: LED Monitors for the Advertising Agency (6 Marks)
Three Advantages of LED Monitors (3 Marks):
1.Superior Colour Accuracy & High Contrast: LED monitors offer vibrant colours, deep blacks, and high dynamic contrast ratios, which are essential for graphic designers and video editors in an advertising agency.
2.Energy Efficiency & Low Heat Emission: LEDs consume significantly less electrical power than CRT or older CCFL-backlit LCD monitors and generate minimal heat during long office hours.
3.Slim, Lightweight Form Factor & Long Lifespan: LED panels are ultra-thin and lightweight (freeing up desk space or allowing multi-monitor wall mounts) and have a long operational lifespan with lower flicker.
Three Disadvantages of LED Monitors (3 Marks):
1.Higher Initial Purchase Cost: High-grade colour-accurate LED monitors have a higher upfront capital cost compared to standard LCD displays.
2.Viewing Angle Colour/Contrast Shift (in non-IPS panels): Some LED panels exhibit brightness or colour shifting when viewed from sharp side angles during team client reviews.
3.Blue Light Emission & Eye Strain: Prolonged high-brightness LED exposure emits blue light that can cause digital eye strain or disrupted sleep if blue-light filters are not configured.
Q.5bExtended Response Questions (ERQs)
2025 Syllabus Outcome (1.5.4): distinguish between open-source, shareware, and freeware software based on their licensing, accessibility, cost, and usage limitations;
Question Text
You work for a non-profit organisation that is looking to switch from proprietary software to a more cost-effective solution.
Explain THREE advantages and THREE disadvantages of using open source software for the organisation's various operations. (6 Marks)
Checking Hints (Marking Scheme • 6 Marks)
  • 1 mark for each explained advantage of open-source software (THREE required = 3 Marks): zero licensing cost, modifiable/auditable source code, no vendor lock-in / active community patches.
  • 1 mark for each explained disadvantage of open-source software (THREE required = 3 Marks): steeper user learning curve/training required, no dedicated official vendor SLA support, file format or hardware driver compatibility issues.
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (6/6)
Part b: Open-Source Software for the Non-Profit Organisation (6 Marks)
Three Advantages of Open-Source Software (3 Marks):
1.Zero Licensing Cost: Open-source software (such as Linux, LibreOffice, and GIMP) is free to download, deploy, and update across unlimited computers, directly reducing the non-profit's software budget.
2.Customisability & Source Code Transparency: Because the source code is publicly accessible, the organisation's developers can inspect, audit, and customise features to fit specific non-profit workflows.
3.No Vendor Lock-In & Strong Community Support: The organisation is not tied to recurring subscription fees from a single vendor and benefits from rapid global community bug fixes and security patches.
Three Disadvantages of Open-Source Software (3 Marks):
1.Steeper Learning Curve & Training Costs: Staff accustomed to commercial proprietary suites (like MS Office or Windows) may require retraining to adapt to open-source interfaces.
2.Lack of Dedicated Official Vendor Support: Unlike commercial software with guaranteed 24/7 SLA helpdesks, support often relies on community forums unless paid third-party support is contracted.
3.Compatibility & Driver Issues: Certain proprietary file formats, specialised peripheral hardware drivers, or legacy donor databases may not work seamlessly with open-source alternatives.
Q.6aExtended Response Questions (ERQs)
2025 Syllabus Outcome (1.9.3): explain guided media and unguided media;
Question Text
A company is considering installing a new network infrastructure in its office. They are exploring different types of guided media and have asked you to explain the advantages and disadvantages of using twisted pair cable.
i.What is twisted pair cable and how does it work? (2 Marks)
ii.Give TWO advantages and TWO disadvantages of using twisted pair cable for network infrastructure. (4 Marks)
Checking Hints (Marking Scheme • 6 Marks)
  • Part i: 1 mark for defining twisted pair cable (insulated copper wires twisted in pairs) + 1 mark for explaining how it works (carries electrical signals while helical twisting cancels EMI and crosstalk).
  • Part ii: 1 mark each for TWO advantages (low cost, easy to install/flexible) + 1 mark each for TWO disadvantages (high attenuation beyond 100m, lower bandwidth / higher EMI susceptibility than fibre-optic cable).
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (6/6)
Part a: Twisted Pair Cable (6 Marks)
i. Definition and Working of Twisted Pair Cable (2 Marks):
•Definition (1 Mark): A twisted pair cable is a guided (wired) copper transmission medium consisting of pairs of insulated copper wires twisted together in a helical spiral (available as Unshielded Twisted Pair — UTP, or Shielded Twisted Pair — STP).
•How It Works (1 Mark): Data is transmitted as electrical signals through the copper conductors; twisting the wire pairs cancels out electromagnetic interference (EMI) and reduces crosstalk from adjacent pairs and external electrical sources.
ii. TWO Advantages and TWO Disadvantages of Twisted Pair Cable (4 Marks):
•Advantages (2 Marks):
1.Low Cost & Wide Availability: It is the least expensive guided medium and is universally supported by standard RJ-45 Ethernet NICs and switches.
2.Easy Installation & Flexibility: The cables are thin, flexible, and easy to terminate and pull through office walls and conduits.
•Disadvantages (2 Marks):
1.Short Distance Limitation (High Attenuation): Signal attenuation restricts standard Ethernet twisted pair segments to a maximum distance of about 100 metres without a repeater/switch.
2.Susceptibility to EMI/Eavesdropping & Lower Bandwidth than Fibre: Compared to fibre-optic cable, copper twisted pair offers lower bandwidth and (especially UTP) remains more vulnerable to strong electromagnetic interference.
Q.6bExtended Response Questions (ERQs)
2025 Syllabus Outcome (1.9.2): explain different types of computer networks, i.e., Local Area Network (LAN), Wide Area Network (WAN), and Metropolitan Area Network (MAN), highlighting their characteristics and applications;
Question Text
i.Describe Metropolitan Area Network (MAN). (2 Marks)
ii.Give TWO advantages and TWO disadvantages of MAN. (4 Marks)
Checking Hints (Marking Scheme • 6 Marks)
  • Part i: 2 marks for describing MAN as a network spanning a city or metropolitan area (5–50 km) that interconnects multiple LANs (e.g., city bank branches, university campuses, cable TV network).
  • Part ii: 1 mark each for TWO advantages (high-speed city-wide LAN interconnection, centralised city resource sharing) + 1 mark each for TWO disadvantages (high installation/leased-line cost, complex multi-site security and maintenance).
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (6/6)
Part b: Metropolitan Area Network (MAN) (6 Marks)
i. Description of Metropolitan Area Network (MAN) (2 Marks):
•A Metropolitan Area Network (MAN) is a high-speed computer network that spans an entire city, town, or large metropolitan campus (typically covering 5 km to 50 km), interconnecting multiple Local Area Networks (LANs) such as city bank branches, university campuses, or cable TV/ municipal fibre networks.
ii. TWO Advantages and TWO Disadvantages of MAN (4 Marks):
•Advantages (2 Marks):
1.Efficient City-Wide Connectivity & Resource Sharing: Connects multiple branch offices or campuses across a city at high speeds (often using fibre-optic backbones) to share centralised databases and internet gateways.
2.Wider Coverage than LAN with Higher Speed than WAN: Bridges the gap between LAN and WAN, offering fast data transfer across a metropolitan region.
•Disadvantages (2 Marks):
1.High Setup & Maintenance Cost: Laying city-wide fibre or leasing metropolitan communication lines requires substantial capital investment and technical administration.
2.Complex Security & Management: Because a MAN spans multiple sites across public metropolitan infrastructure, securing it against unauthorised access/hackers is more complex than managing a single-building LAN.