Hitachi HDS723020BLA642 - Acoustics; Table 21 Sound Power Levels

Hitachi hard disk drive specifications
42
6.7 Acoustics
The upper limit criteria of the octave sound power levels are given in Bels relative to one picowatt and are shown
in the following table. The sound power emission levels are measured in accordance with ISO 7779.
Mode
7200rpm (Typical / Max)
Idle
2.7 / 2.8
Operating
2.8 / 3.0
Table 21 Sound power levels
Mode definition:
Idle mode. The drive is powered on, disks spinning, track following, unit ready to receive and respond to
interface commands.
Operating mode. Continuous random cylinder selection and seek operation of the actuator with a dwell
time at each cylinder. The seek rate for the drive is to be calculated as shown below:
 Dwell time = 0.5 x 60/RPM
 Seek rate = 0.4 / (Average seek time + Dwell time)