2. Computer Organisation

Question 1

1. Identify the main components of the Central Processing Unit (CPU) and describe their functions. (4 marks)

Answer 1

• Arithmetic Logic Unit (ALU): Performs calculations and logic operations (1).
  
  • Control Unit (CU): Directs operations and instructions within the CPU (1).
  • Registers: Small, fast memory for immediate data access (1).
  • Cache: Temporary storage for frequently used data, enhancing speed (1).

Question 2

2. Explain the Fetch-Decode-Execute cycle in a CPU. (6 marks)

Answer 2

• Fetch: Retrieves instruction from memory (1).
  
  • Decode: Interprets instruction in the CU (1).
  • Execute: Carries out the instruction using ALU or other CPU parts (1).
  • Cycle repeats to complete program execution (1).
  • Importance: Ensures sequential execution of instructions (1).
  • Efficiency: Faster cycle = better CPU performance (1).

Question 3

3. Describe the differences between primary and secondary memory and provide examples. (4 marks)

Answer 3

• Primary memory: Temporary storage, fast access (e.g., RAM) (2).
  
  • Secondary memory: Long-term storage, slower access (e.g., hard drive) (2).

Question 4

4. Outline how clock speed, number of cores, and cache memory affect CPU performance. (6 marks)

Answer 4

• Clock speed: Faster speed means quicker execution of instructions (2).
  
  • Number of cores: More cores allow parallel processing (2).
  • Cache memory: Reduces access time by storing frequently used data (2).

Question 5

5. Compare the characteristics and uses of RAM and ROM. (4 marks)

Answer 5

• RAM: Volatile, used for temporary data storage while running programs (2).
  
  • ROM: Non-volatile, stores critical instructions like boot firmware (2).

Question 6

6. Explain the differences between volatile and non-volatile memory, giving examples. (3 marks)

Answer 6

• Volatile: Data lost when power is off, e.g., RAM (1).
  
  • Non-volatile: Data retained without power, e.g., SSD, HDD (1).
  • Importance: Determines data persistence and backup needs (1).

Question 7

7. Describe how virtual memory works and explain its importance in modern computers. (5 marks)

Answer 7

• Virtual memory: Uses hard drive space to extend RAM capacity (2).
  
  • Mechanism: Swaps inactive data from RAM to storage (1).
  • Importance: Allows multitasking beyond physical RAM limits (2).

Question 8

8. Compare and contrast SSD and HDD in terms of speed, durability, and cost. (4 marks)

Answer 8

• Speed: SSDs are faster than HDDs (1).
  
  • Durability: SSDs are more shock-resistant; no moving parts (1).
  • Cost: SSDs are more expensive per GB than HDDs (1).
  • Use cases: SSDs for performance; HDDs for cost-effective storage (1).

Question 9

9. Outline the purpose of cache memory and explain its role in improving performance. (5 marks)

Answer 9

• Purpose: Stores frequently accessed data close to CPU (2).
  
  • Role: Reduces fetch time for data/instructions (2).
  • Impact: Enhances system responsiveness and CPU efficiency (1).

Question 10

10. Explain ‘memory hierarchy’ and arrange components by speed. (3 marks)

Answer 10

• Definition: Layers of memory ranked by speed and size (1).
  
  • Order: Registers > Cache > RAM > Secondary Storage (2).

Question 11

11. List four functions of an operating system and describe each briefly. (4 marks)

Answer 11

• Memory Management: Manages RAM usage (1).
  
  • Process Management: Handles task execution and scheduling (1).
  • File Management: Organises and stores files (1).
  • Device Management: Manages hardware through drivers (1).

Question 12

12. Explain the difference between multitasking and multiprocessing. (4 marks)

Answer 12

• Multitasking: Switching between tasks on one CPU (2).
  
  • Multiprocessing: Using multiple CPUs/cores for simultaneous tasks (2).

Question 13

13. Describe the role of device drivers within an OS. (3 marks)

Answer 13

• Role: Enables communication between hardware and OS (2).
  
  • Example: Printer driver allows OS to interact with printer (1).

Question 14

14. Define ‘kernel’ and ‘user interface’ in an OS and explain their roles. (5 marks)

Answer 14

• Kernel: Core part of OS, manages hardware and system processes (2).
  
  • User Interface: Allows user interaction with OS, e.g., GUI or CLI (2).
  • Importance: Kernel enables system control; UI offers user access (1).

Question 15

15. Explain why file management is essential in an OS. (3 marks)

Answer 15

• Importance: Organises storage for data retrieval (1).
  
  • Supports data hierarchy and access rights (1).
  • Enhances user and system efficiency (1).