Abstract
Unstable vibration of the head assembly in flexible disk drives (FDD) induces read and write errors, and it decreases the life expectancy of the magnetic memory. This study experimentally analyzes the unstable Vibration using an FDD unit modified to rotate at variable speeds. The unstable vibration of the disk is measured by a non-contact photosensor. The head vibrates in a pitching mode and the disk vibrates toward the head in a wave-train mode ; these modes are coupled. Instability occurs only within a certain speed range, and the frequency of unstable vibration increases as rotational speed increases.
