Particle contamination in a hard disk drive has been recognized as an impor
tant issue because particles can significantly affect the reliability of th
e drive. In this study, characteristics of the particle generation in a har
d disk drive during the start/stop period were investigated. The number of
particles generated in the drive was measured at 5 locations using CNC (con
densation nucleus counter) with a sampling probe. It was found that most of
particles were generated whenever the drive started or stopped. The number
of particles detected by the condensation nucleus counter depended on para
meters including sampling location and sampling velocity.