Using compact disc player optical systems to measure differentially hard disk drive slider and disk motion under hostile conditions

When typical hard disk drives are subjected to vibration, data transfer failure was found to be particularly significant at frequencies between 450 and 700 Hz At non-critical frequencies of vibration the typical hard disk drive is capable of reliably transferring data whilst subjected to as much as 45 g of vibration. However, between 450 and 700 Hz they typically fail to transfer data at as little as 1 g. These data failures can be attributed to two key components: the suspension arm and the hard disk. An optical system, based on CD-ROM optics, has been developed to unobtrusively measure disk flutter and flying height variations, and to validate measurements made using PVdF sensors