Which metric can be used to measure the data transfer performance of a hard disk drive?

• A. Disk capacity
• B. Rotation speed
• C. Data transfer rate
• D. Average access time

Answer: (C)

Data transfer rate is the metric that measures how much data can be moved between the disk and the host per unit time. For a hard disk drive, this reflects the sustained sequential read/write throughput, typically expressed in MB/s, and directly indicates transfer performance during continuous data operations. Disk capacity only tells you how much can be stored, not how fast data moves. Rotation speed influences mechanical access and data density but does not itself quantify transfer speed. Average access time measures latency to start an operation, not the ongoing rate of data transfer. So the data transfer rate best captures the drive’s data movement performance.