Section A
Instructions: Attempt any TWO questions. Total marks: (2×10 = 20)
Question 1 (7+3 marks)
Describe different types of software with their roles.
Software is categorized into two primary types: system software and application software.
- System Software:
- Role: Manages and controls computer hardware, providing a platform for application software to operate.
- Examples:
- Operating Systems (OS): Such as Windows, macOS, and Linux, which manage hardware resources like memory, CPU, and storage, and provide user interfaces.
- Utility Programs: Including antivirus software (e.g., Norton), disk management tools, and file compression tools, which assist in maintaining system performance.
- Device Drivers: Software that enables communication between the OS and hardware devices like printers or graphics cards.
- Purpose: Ensures the computer operates efficiently and provides essential services to applications.
- Application Software:
- Role: Enables users to perform specific tasks tailored to their needs.
- Examples:
- Productivity Software: Such as Microsoft Word (word processing) and Excel (spreadsheets).
- Web Browsers: Like Google Chrome or Firefox, for accessing the internet.
- Entertainment Software: Including games (e.g., Minecraft) and media players (e.g., VLC).
- Database Management Systems: Such as MySQL, for organizing and retrieving data.
- Purpose: Addresses user-specific requirements, from work to leisure.
In essence, system software keeps the computer running, while application software makes it useful for users.
How do system software and application software interact with each other to provide a seamless computing experience?
System software and application software work together through a layered interaction:
- Role of System Software: The operating system acts as an intermediary, managing hardware resources (e.g., CPU, memory, storage) and providing services like file handling, process management, and input/output operations.
- Application Software Requests: Applications use system calls or APIs (Application Programming Interfaces) to request these services. For example, when a user saves a document in a word processor, the application instructs the OS to write the file to the disk.
- Seamless Experience: The OS abstracts hardware complexities, allowing applications to focus on user tasks without managing low-level details. This ensures compatibility, efficiency, and stability across diverse hardware.
For instance, a game relies on the OS to allocate memory and process graphics card commands, delivering a smooth experience to the player. This collaboration ensures users can work or play without interruptions.
Question 2 (6+4 marks)
Describe different network topologies along with their advantages and disadvantages.
Network topologies describe how devices are physically or logically connected in a network. Here are the main types:
- Bus Topology:
- Description: All devices connect to a single central cable (the bus).
- Advantages:
- Simple and inexpensive to set up.
- Requires less cable than other topologies.
- Disadvantages:
- Single point of failure: If the bus cable fails, the entire network stops.
- Limited scalability: Adding devices degrades performance.
- Star Topology:
- Description: Devices connect to a central hub or switch.
- Advantages:
- Easy to troubleshoot: Issues are isolated to individual connections.
- Scalable: New devices can be added easily.
- Disadvantages:
- Hub dependency: If the central hub fails, the network collapses.
- Higher cost due to additional hardware (hub/switch).
- Ring Topology:
- Description: Devices form a closed loop, each connected to two others.
- Advantages:
- Predictable data flow reduces collisions.
- Equal access for all devices.
- Disadvantages:
- Difficult to reconfigure: Adding/removing devices disrupts the ring.
- Single failure can break the network unless dual-ring is used.
- Mesh Topology:
- Description: Every device connects to every other device.
- Advantages:
- Highly reliable: Multiple paths ensure data delivery even if one link fails.
- Robust and fault-tolerant.
- Disadvantages:
- Expensive and complex: Requires extensive cabling and setup.
Each topology suits different needs based on cost, reliability, and scale.
Explain how networking transformed sectors such as education, business, and healthcare.
Networking has reshaped these sectors by enhancing connectivity and access:
- Education:
- Transformation: Online platforms (e.g., Zoom, Moodle) enable remote learning, virtual classrooms, and access to global resources like e-libraries.
- Impact: Increases accessibility for students worldwide and supports interactive, multimedia-based education.
- Business:
- Transformation: E-commerce (e.g., Amazon), remote work tools (e.g., Microsoft Teams), and cloud services facilitate global trade and collaboration.
- Impact: Expands market reach, reduces operational costs, and enables 24/7 operations.
- Healthcare:
- Transformation: Telemedicine, electronic health records (EHRs), and networked medical devices allow remote consultations and data sharing.
- Impact: Improves patient care, enables real-time monitoring, and accelerates medical research.
Networking drives efficiency, accessibility, and innovation across these fields.
Question 3 (3+2+5 marks)
Explain the concept of memory hierarchy.
Memory hierarchy is the organization of computer memory into levels based on speed, cost, and capacity:
- Registers: Fastest, smallest, and most expensive; located in the CPU for immediate data access.
- Cache Memory: Fast, small memory near the CPU; stores frequently used data to reduce access time.
- Main Memory (RAM): Larger and slower than cache; holds active programs and data.
- Secondary Storage: Largest, slowest, and cheapest (e.g., HDDs, SSDs); used for long-term data storage.
This hierarchy balances performance and cost, placing critical data in fast memory and bulk data in slower, affordable storage.
How does the hierarchy affect the performance of a computer system?
The memory hierarchy enhances performance by:
- Speed Optimization: Frequently accessed data resides in fast memory (e.g., cache, registers), reducing CPU wait times.
- Cost Efficiency: Less-used data is stored in cheaper, slower memory (e.g., HDDs), keeping expenses low.
- Resource Management: Ensures the CPU accesses data efficiently, improving overall system speed.
For example, a program’s active instructions in cache are accessed quickly, while archived files on a hard drive take longer but don’t clog faster memory.
Explain the difference between hardcopy and softcopy output devices with examples.
- Hardcopy Output Devices:
- Definition: Produce physical, tangible outputs.
- Examples:
- Printers: Print text or images on paper (e.g., inkjet printers).
- Plotters: Create large-scale drawings (e.g., blueprints).
- Characteristics: Permanent, portable, but not editable once produced.
- Softcopy Output Devices:
- Definition: Produce digital or electronic outputs.
- Examples:
- Monitors: Display visual output (e.g., computer screens).
- Speakers: Output sound (e.g., audio from a video).
- Characteristics: Temporary, editable, and requires a device to view/hear.
The main distinction is physical versus digital output, each serving different user needs.
Section B
Instructions: Attempt any EIGHT questions. Total marks: (8×5 = 40)
Question 4 (1+4 marks)
List out the characteristics of a computer.
Computers possess these key traits:
- Speed: Processes tasks rapidly.
- Accuracy: Delivers precise results.
- Diligence: Works tirelessly without errors.
- Versatility: Handles diverse tasks.
- Storage Capacity: Stores vast data.
- Automation: Executes tasks automatically.
- Reliability: Provides consistent performance.
How do these characteristics make computers efficient for various applications?
- Speed: Enables quick data processing (e.g., simulations in science).
- Accuracy: Ensures error-free calculations (e.g., financial records).
- Diligence: Supports continuous operation (e.g., server uptime).
- Versatility: Adapts to tasks like gaming, coding, or design.
- Storage Capacity: Manages large datasets (e.g., databases).
- Automation: Reduces human effort (e.g., assembly lines).
- Reliability: Ensures dependable outcomes (e.g., medical diagnostics).
These traits make computers indispensable across industries.
Question 5 (5 marks)
Compare and contrast primary memory and secondary memory.
| Feature | Primary Memory | Secondary Memory |
|---|---|---|
| Volatility | Volatile (loses data when off) | Non-volatile (retains data) |
| Speed | Fast access | Slower access |
| Capacity | Smaller (e.g., GBs) | Larger (e.g., TBs) |
| Cost | Expensive per byte | Cheaper per byte |
| Examples | RAM, Cache | HDDs, SSDs, USB drives |
| CPU Access | Direct | Indirect (via RAM) |
Summary: Primary memory (e.g., RAM) is fast, temporary storage for active tasks, while secondary memory (e.g., hard drives) offers permanent, high-capacity storage.
Question 6 (3+2 marks)
Describe the different phases of the instruction cycle.
The instruction cycle has four phases:
- Fetch: CPU retrieves an instruction from memory.
- Decode: CPU interprets the instruction’s meaning.
- Execute: CPU performs the instruction (e.g., arithmetic operation).
- Store: CPU saves the result to memory or registers.
How does it help in executing a program?
The cycle ensures:
- Instructions are fetched accurately.
- Decoded correctly for execution.
- Executed efficiently.
- Results are stored for further use.
This step-by-step process allows programs to run systematically.
Question 7 (3+2 marks)
Convert the binary number 110101.101 to its equivalent octal and hexadecimal representations.
- Binary to Octal:
- Group into threes from the decimal point:
- Left: 110 101 → 6 5 (110 = 6, 101 = 5).
- Right: 101 → 5 (101 = 5).
- Result: 65.5₈.
- Group into threes from the decimal point:
- Binary to Hexadecimal:
- Group into fours from the decimal point:
- Left: 0011 0101 → 3 5 (0011 = 3, 0101 = 5).
- Right: 1010 → A (1010 = 10 = A).
- Result: 35.A₁₆.
- Group into fours from the decimal point:
(Note: Leading zeros were added for complete groups.)
Question 8 (2+2+1 marks)
Describe the different layers in the internet architecture and how each layer contributes to internet communication.
The TCP/IP model defines four layers:
- Application Layer:
- Description: Manages user-facing services (e.g., HTTP, FTP).
- Contribution: Formats data for applications like web browsing.
- Transport Layer:
- Description: Handles data transfer (e.g., TCP for reliability, UDP for speed).
- Contribution: Ensures data reaches its destination correctly.
- Internet Layer:
- Description: Manages addressing and routing (e.g., IP).
- Contribution: Directs data packets across networks.
- Network Access Layer:
- Description: Controls physical data transmission (e.g., Ethernet).
- Contribution: Sends data over hardware like cables or Wi-Fi.
Together, these layers enable seamless global communication.
Question 9 (1+4 marks)
What is a database?
A database is an organized collection of structured data, stored electronically and managed by a database management system (DBMS) for efficient access and manipulation.
Explain how databases support operations in business, social media, finance, and healthcare.
- Business: Stores customer data, sales, and inventory (e.g., CRM systems).
- Social Media: Manages user profiles and posts (e.g., Facebook’s database).
- Finance: Tracks transactions and accounts (e.g., banking systems).
- Healthcare: Holds patient records and research data (e.g., EHRs).
Databases provide fast retrieval, organization, and analysis, supporting critical operations.
Question 10 (1+4 marks)
Explain how multimedia applications enhance user experience in areas like online learning, gaming, and virtual reality.
Multimedia integrates text, audio, images, and video:
- Online Learning: Videos and animations (e.g., Khan Academy) make lessons engaging and clear.
- Gaming: Graphics and sound (e.g., Fortnite) create immersive worlds.
- Virtual Reality: 3D visuals and audio (e.g., VR training) simulate reality.
These elements boost interactivity and enjoyment.
Question 11 (5 marks)
Why computer security is essential?
Computer security protects:
- Data from theft or loss.
- Systems from disruptions.
- Privacy and confidentiality.
- Against financial and reputational damage.
Explain how confidentiality and integrity services are maintained.
- Confidentiality:
- Encryption: Scrambles data (e.g., AES).
- Access Controls: Limits access (e.g., passwords).
- Integrity:
- Checksums: Detects changes.
- Digital Signatures: Verifies authenticity.
These ensure data remains private and unaltered.
Question 12 (2+2+1=5 marks)
Write short notes on:
a) Big Data:
- Large, complex datasets requiring advanced tools (e.g., Hadoop) to process. Used in analytics for insights in marketing, science, etc.
b) E-Commerce:
- Online buying/selling (e.g., Amazon). Expands markets and streamlines transactions via the internet.