The storage system has been increasing its data capacity and I/O performance. Larger capacity per a hard disk drive (HDD) requires more highly accurate head positioning control and higher performance leads larger power consumption of equipment (MPUs, memories, and HDDs) and faster fan speed to cool them. Head positioning errors (PESs) caused by acoustic excitation due to the cooling fans has been a common issue between HDD manufactures and storage box designers. And, to quantify acoustic excitations in a storage box is also the common need. We have proposed a 3.5” HDD acoustic surrogate as a measurement tool for the acoustic excitations. It has similar size and shape with a 3.5” HDD and uses two 1/4” size condenser microphones. The key idea is to model the acoustic excitations with diffuse sound field, and we showed measured sound data represents for actual acoustic excitations to an HDD by comparing PES/sound ratios. This paper reports how we determined the number and locations of microphones of the acoustic surrogate experimentally.
Eguchi et al. (Wed,) studied this question.