Ok, there was some confusion about what HDDs do when they do a soft or hard stop.
I found this whitepaper by Hitachi(former IBM) about the issue. Shortly, head unloading is used mostly only in mobile drives (2.5" and smaller for notebooks). It also works in emergencies, where the head is unloaded by drawing the power from a dynamo powered by the rotational momentum of the spindle. In most desktop drives, the heads _do_ rest on the disk surface when not powered. Usually today with the high capacity disks, they rest on a special textured area where data aren't stored. Seemingly, with a power failure, they won't return there :( Only now some desktop drives employ head unloading (incl. emergency unloading), especially bigger server drives and just now even some smaller desktop drives. See all the technical details here: http://www.hitachigst.com/hdd/library/whitepap/load/load.htm >From my layman's view, my next 3.5" desktop HDD will be 100% with head unloading. Frantisek
