Sridhar Ayengar asks: Well, I've seen how much dust a car air filter lets through, and I won't use one on my car anymore. 8-/ Do the heads on older drives hover closer or farther from the data surface than on newer drives? Peace... Sridhar Billy wrote: All of the early cartridge drives used HEPA filters with no problems. Provided you changed them when required by maintenance schedules. Current drives still use a paper type filter but it is inside the drive and not replaceable. Some of the higher speed drives (10-14K RPM) may have two internal filters and a third over the pressure equalization hole. Older drive heads of the ST412 era were in the 40-70 micro inch range. New drives with Dynamic Flying Height ability are in the 1-3 micro inch range. They also deliberately touch the media during the initial calibration cycles. This is usually only once per head during the life of the drive. There is no harm from this touch. Billy