Which of the following best describes the function of the Key Register in an…
2025
Which of the following best describes the function of the Key Register in an associative (content-addressable) memory system?
- A.
It tracks the number of hits and misses during memory access.
- B.
It holds the data to be compared with the stored addresses in memory.
- C.
It maintains a list of available memory locations.
- D.
It stores the physical address of memory blocks.
Attempted by 84 students.
Show answer & explanation
Correct answer: B
In an associative memory system, also known as content-addressable memory (CAM), the primary function is to retrieve data based on its content rather than a specific address. The Key Register plays a critical role in this process by holding the search key or data value that needs to be compared against all stored entries simultaneously. When a lookup operation occurs, the content in the Key Register is broadcast to every memory cell for parallel comparison. If a match is found, the corresponding data or address is returned. Option B correctly identifies this function as holding the comparison data.
Option A describes performance monitoring rather than memory operation logic.
Option C refers to a free list or allocation table, which is unrelated to the core CAM comparison mechanism.
Option D describes a standard address register in conventional memory systems, not the search key function specific to associative memory.