Access Time Test
Modern IDE hard drives need at least 11 ms on average to access one sector or file. If the manufacturer states shorter access times, these generally refer to the pure seek times, which do not take into account rotational latency or the time it takes to initiate the read operation. Rotational latency describes the time it takes for the requested sectors to "pass by" the read heads once these have been aligned.
I/O Benchmark
It came as no surprise that a modern hard drive is able to execute more transfers per second than the older models in this test. What was astonishing, however, was the DTTA series from IBM, which should be more up-to-date and work faster than the much older Fireball ST series from Quantum.
The reason for this can be found in its market alignment. While the Fireball ST was a high-end drive, the 5,400 rpm DTTA was designed for the mass market. IBM's portfolio included a drive with 7,200 rpm for performance-hungry applications.