Question

Which of the following is the correct sequence of memory hierarchy from fastest to slowest?

• A. Registers $>$ Cache $>$ RAM $>$ Disk
• B. Disk $>$ RAM $>$ Cache $>$ Registers
• C. RAM $>$ Registers $>$ Disk $>$ Cache
• D. Registers $>$ Disk $>$ RAM $>$ Cache

Hint:

To understand memory hierarchy:
- Remember: Registers (fastest), Cache, RAM, Disk (slowest).
- Speed decreases as capacity and cost per unit increase.
- Study CPU design to see how these levels interact.

Answer 1

The Correct Option is A

To determine the correct sequence of the memory hierarchy from fastest to slowest, we need to understand the relative speeds of different memory types in a computer system.
Step 1: Understand the Memory Hierarchy 
The memory hierarchy is designed to balance speed and cost, with faster memory being smaller and more expensive, and slower memory being larger and cheaper. 
The typical order from fastest to slowest is: Registers, Cache, RAM (Random Access Memory), and Disk. 
Step 2: Analyze Option A - Registers $>$ Cache $>$ RAM $>$ Disk 
- Registers are the fastest memory, located inside the CPU for immediate data access. 
- Cache is faster than RAM, serving as a buffer between the CPU and main memory. 
- RAM is slower than Cache but faster than Disk, used for primary storage. 
- Disk (e.g., HDD or SSD) is the slowest, used for long-term storage. 
This sequence matches the standard memory hierarchy from fastest to slowest. 
Thus, option A is correct. 
Step 3: Analyze Option B - Disk $>$ RAM $>$ Cache $>$ Registers 
This reverses the hierarchy, placing the slowest memory (Disk) first and the fastest (Registers) last. 
This is incorrect as it contradicts the known speed order. 
Thus, option B is incorrect. 
Step 4: Analyze Option C - RAM $>$ Registers $>$ Disk $>$ Cache 
This sequence is incorrect because Registers are faster than RAM, and Cache is faster than Disk. 
The order does not align with the memory hierarchy. 
Thus, option C is incorrect. 
Step 5: Analyze Option D - Registers $>$ Disk $>$ RAM $>$ Cache 
This sequence places Disk before RAM and Cache, which is wrong since Disk is slower than both RAM and Cache. 
Thus, option D is incorrect. 
Step 6: Conclusion 
The correct order, based on speed from fastest to slowest, is Registers $>$ Cache $>$ RAM $>$ Disk, making option A the answer.