Memory Management Knowledge Check Which of the following statements is TRUE?

Introduction / Context:
Operating systems rely on page-replacement algorithms, virtual memory management, and storage performance analysis. Distinguishing correct statements from common misconceptions helps solidify foundational knowledge.

Given Data / Assumptions:

• LRU stands for Least Recently Used, a common approximation of optimal replacement.
• Thrashing can occur under poor working-set management but is not inevitable.
• Seek analysis examines disk head movement and latency—tied to device behavior.

Concept / Approach:
Validate each statement against standard OS theory and storage performance practice. Select the single statement that is unambiguously true.

Step-by-Step Solution:
LRU: By definition, evicts the page whose last use is farthest in the past (i.e., not used recently). This statement is true.Thrashing: Not a “natural consequence”; it results when the total working set of active processes exceeds available frames, causing excessive paging. Proper controls prevent it.Seek analysis: Targets disk device performance (seek and rotational delays), not primarily control-unit busy conditions. Hence this statement, as phrased, is false.

Verification / Alternative check:
Textbook definitions and OS labs demonstrate LRU behavior and show thrashing can be avoided by adjusting the degree of multiprogramming or by using working-set models.

Why Other Options Are Wrong:
Option B exaggerates; virtual memory does not mandate thrashing.Option C misattributes seek analysis to controller bottlenecks rather than disk mechanics.“All of the above” fails because B and C are incorrect.

Common Pitfalls:

• Confusing LRU with MRU (Most Recently Used).
• Assuming thrashing is unavoidable instead of workload- and configuration-dependent.
• Mixing up controller throughput and spindle/seek latencies.

Final Answer:
The LRU page-replacement algorithm evicts pages that have not been used recently.