fly >when at speed, they do have to drag on the surface. For this they also >put a very thin layer of lub on the surfaces. Billy Pettit has been surprisingly quiet about all of this... The one case of lubricant stiction I know of for a fact is in Quantum Q540. Apple had a huge field failure problem because of this in HD40s. They modified the firmware to giggle the head on powerup to help prevent landing zone lubricant accumulation.