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Computer Science IX · 2023 · E-Marking Notes (Questions & Solved Better Responses)

AGA KHAN UNIVERSITY EXAMINATION BOARD
Notes from E-Marking Centre on SSC-I Computer Science Annual Examinations 2023
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
Computer operating systems have evolved since the first computers used the Command Line Interface (CLI). Nowadays, many computers use Graphical User Interface (GUI).
Give TWO advantages and TWO disadvantages of using GUI. (4 Marks)
Checking Hints (Marking Scheme • 4 Marks)
  • 1 mark for each correct advantage of GUI (Any TWO required).
  • 1 mark for each correct disadvantage of GUI (Any TWO required).
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (4/4)
Two Advantages of Graphical User Interface (GUI) (2 Marks):
1.User-Friendly & Easy to Learn: Users interact visually via icons, windows, menus, and a mouse pointer (WIMP) without having to memorise complex text commands or exact syntax.
2.Intuitive Multitasking & Visual Feedback: Multiple applications can be viewed side-by-side in separate windows with drag-and-drop file operations and immediate visual alerts.
Two Disadvantages of Graphical User Interface (GUI) (2 Marks):
1.Higher System Resource Consumption: Rendering graphics, windows, and icons requires significantly more RAM, disk space, and CPU/GPU processing power than a CLI.
2.Slower Execution for Repetitive/Scripting Tasks: Navigating nested menus with a mouse is slower than executing a direct CLI command or automated shell script.
Q.2Constructed Response Questions (CRQs)
Out of 2025 Syllabus2 Marks • Level U
Question Text
Give any TWO differences between analog and digital signals. (2 Marks)
Checking Hints (Marking Scheme • 2 Marks)
  • 1 mark for each correct difference (TWO required).
  • No mark for any incomplete difference (point written in only one column).
  • Note: marks to be awarded for accuracy whether mentioned in digital or analog.
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (2/2)
AspectAnalog SignalsDigital Signals
1. Nature of WaveformContinuous electromagnetic wave that varies smoothly over time and can take any infinite value within a range (sine wave).Discrete, non-continuous square pulses representing binary values (0s and 1s / low and high voltage levels).
2. Noise Immunity & SpeedMore susceptible to noise and attenuation during transmission; lower transmission speed in modern computing.Highly resistant to noise/degradation (easily regenerated) and offers faster digital data processing and transmission.
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
a. Draw the diagram of star topology. (1 Mark)
b. Give any ONE advantage of using this topology. (1 Mark)
Checking Hints (Marking Scheme • 2 Marks)
  • 1 mark for the correct diagram of star topology.
  • 1 mark for the advantage (Any ONE required).
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (2/2)
a. Diagram of Star Topology (1 Mark):
Architecture / Topology Diagram
      [Computer 1]         [Computer 2]
            \                 /
             \               /
              [Central Switch/Hub]
             /               \
            /                 \
      [Computer 3]         [Computer 4]
(Multiple computer nodes each connected via an individual point-to-point cable directly to a central Switch or Hub.)
b. ONE Advantage of Star Topology (1 Mark):
•Fault Isolation / Reliability: If a single node or its cable fails/breaks, the rest of the network continues operating normally without disruption.
•(Alternative valid point) Easy Troubleshooting & Scalability: Faulty cables are easy to identify at the central switch, and new nodes can be added without shutting down the network.
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 web page (Fruits — displaying heading Fruits followed by a definition list: Peach: Fruit with one seed, Papaya: Fruit with many seeds).
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> and </html> tags.
  • 1 mark for <body> and </body> tags.
  • 1 mark for <dl> and </dl> tag in the correct place.
  • 1 mark for <dt> and </dt> tag in the correct place.
  • 1 mark for <dd> and </dd> tag in the correct place.
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (5/5)
HTMLSource Code
<html>
<head>
    <title>Fruits</title>
</head>
<body>
    <h1>Fruits</h1>
    <dl>
        <dt>Peach</dt>
        <dd>Fruit with one seed</dd>
        <dt>Papaya</dt>
        <dd>Fruit with many seeds</dd>
    </dl>
</body>
</html>
Q.5aExtended Response Questions (ERQs)
2025 Syllabus Outcome (1.2.3): describe primary and secondary storage devices based on location, cost, capacity, access time, data processing method, and storage technology such as semiconductor (SSD), magnetic (HDD), and optical;
Question Text
a. Describe the term hard disk drive (HDD). (2 Marks)
b. Give any FOUR reasons why hard disk drives (HDD) are being replaced by solid-state drives (SSD). (4 Marks)
Checking Hints (Marking Scheme • 6 Marks)
  • 1 mark for each highlighted statement for HDD (TWO required = 2 Marks).
  • 1 mark for each correct reason why HDDs are being replaced by SSDs (FOUR required = 4 Marks).
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (6/6)
Part a: Hard Disk Drive (HDD) vs Solid-State Drive (SSD) (6 Marks)
i. Description of Hard Disk Drive (HDD) (2 Marks):
•A Hard Disk Drive (HDD) is a non-volatile magnetic secondary storage device used for storing the operating system, software applications, and user files permanently.
•It consists of one or more circular magnetic platters (divided into concentric tracks and sectors) that spin rapidly while mechanical read/write heads read and write data magnetically.
ii. FOUR Reasons Why HDDs Are Being Replaced by SSDs (4 Marks):
1.Significantly Faster Read/Write & Boot Speed: SSDs use semiconductor NAND flash memory with near-instantaneous random access, booting OS and loading apps several times faster than mechanical HDDs.
2.No Moving Parts & Higher Durability: Unlike HDDs (which have spinning platters and fragile read/write heads), SSDs have no mechanical moving parts, making them shock-resistant and durable against drops.
3.Silent Operation & Less Heat Generation: Because SSDs have no spinning motor or moving actuator arm, they operate completely silently and emit far less heat.
4.Lighter Weight, Compact Size & Lower Power Consumption: SSDs (especially M.2 NVMe drives) are much smaller, lighter, and consume less battery power, making them ideal for modern laptops.
Q.5bExtended Response Questions (ERQs)
Out of 2025 Syllabus6 Marks • Level U
Question Text
a. Name the basic operations of a computer. (2 Marks)
b. Describe each basic operation of a computer. (4 Marks)
Checking Hints (Marking Scheme • 6 Marks)
  • 1 mark for naming TWO operations (FOUR operations required = 2 Marks; no marks if only one operation is named; 1 mark if three names are written).
  • 1 mark for each description (FOUR required = 4 Marks).
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (6/6)
Part b: Basic Operations of a Computer (Data Processing Cycle) (6 Marks)
i. Names of the Four Basic Operations of a Computer (2 Marks):
1.Input Operation
2.Processing Operation
3.Storage Operation
4.Output Operation
ii. Description of Each Basic Operation (4 Marks):
1.Input Operation (1 Mark): The process of accepting raw data and instructions from the user or environment via input devices (such as a keyboard, mouse, or scanner) and transferring them into main memory.
2.Processing Operation (1 Mark): Performed by the Central Processing Unit (CPU — ALU and Control Unit), which fetches instructions and data from memory, decodes them, and executes arithmetic or logical operations to transform raw data into meaningful information.
3.Storage Operation (1 Mark): The process of holding data, instructions, and processed results either temporarily in primary memory (RAM) during execution or permanently on secondary storage (HDD/SSD) for future retrieval.
4.Output Operation (1 Mark): The process of presenting the processed result (information) to the user in human-readable form via output devices such as a monitor (softcopy), printer (hardcopy), or speakers.
Q.6aExtended Response Questions (ERQs)
2025 Syllabus Outcome (1.9.3): explain guided media and unguided media;
Question Text
a. Write TWO differences between guided (wired) and unguided (wireless) media. (2 Marks)
b. Describe any TWO examples of guided media. (4 Marks)
Checking Hints (Marking Scheme • 6 Marks)
  • 1 mark for each complete difference between guided and unguided media (Any TWO required = 2 Marks; no marks if the difference is incomplete).
  • 1 mark for each statement in each guided media description (Any TWO statements required for each of the TWO examples = 4 Marks).
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (6/6)
Part a: Guided vs Unguided Media (6 Marks)
i. TWO Differences Between Guided (Wired) and Unguided (Wireless) Media (2 Marks):
| Aspect | Guided (Wired) Media | Unguided (Wireless) Media |
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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
Explain Local Area Network (LAN) and Wide Area Network (WAN) with the help of TWO characteristics and a diagram of each. (6 Marks)
Checking Hints (Marking Scheme • 6 Marks)
  • 1 mark for the diagram of LAN.
  • 1 mark for the diagram of WAN.
  • 1 mark for the description of LAN.
  • 1 mark for the description of WAN.
  • 1 mark for any TWO characteristics of LAN.
  • 1 mark for any TWO characteristics of WAN.
✓ BETTER RESPONSE (SOLVED MODEL ANSWER)Full Marks (6/6)
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