Which statement best describes HDDs vs SSDs in terms of latency and maintenance needs?

• A. HDDs have mechanical latency; SSDs have lower latency and higher throughput; SSDs do not wear out.
• B. SSDs have higher latency than HDDs.
• C. TRIM is not supported on SSDs.
• D. HDDs have mechanical latency; SSDs have lower latency and higher throughput; SSDs require wear leveling and TRIM support to maintain performance.

Answer: (D)

Latency matters: spinning hard drives have mechanical parts that must move and wait for the platter to rotate, so their access times are higher and overall latency is larger. Solid-state drives use flash memory with no moving parts, so access is almost immediate, giving much lower latency and higher throughput, especially for random reads and writes.

Maintenance matters too: SSDs wear out because flash cells have a finite number of program/erase cycles, so wear leveling spreads writes evenly to extend life. TRIM helps by informing the drive which blocks are no longer in use, allowing garbage collection to reclaim space and keep performance from degrading over time. HDDs don’t rely on wear leveling or TRIM in the same way, so those maintenance concepts are not as applicable.

The other statements don’t fit because one wrongly claims SSDs never wear out, another says SSDs have higher latency than HDDs, and another incorrectly claims TRIM isn’t supported on SSDs. The described combination—HDDs with mechanical latency, SSDs with lower latency and higher throughput, and SSD-specific maintenance like wear leveling and TRIM—best matches how these drives behave in practice.