On Thursday, August 19, 2010 02:27:03 am Tim did opine: > On Wed, 2010-08-18 at 13:38 -0400, Gene Heskett wrote: > > Subtly mixed in with this might be a longer than normal spinup time at > > powerup, leading to higher head wear in the first turn or two of the > > spinup, > > I wouldn't have thought that would happen. The heads don't touch the > drive in operation, and I thought parking the heads moved the arm > completely off the disc. It's been a while since they have been parked off disk. None of the drives I have opened up in the last decade did anything but park them at a non- data bearing location on the disk. This can often be identified by a thin line of slightly higher polish on the surface. They use very little pressure these days, and with decent brakes, usually by shorting the drive motor when stopping, the time the head actually touches the disk is very short, likewise when spinning up, the head takes off and flies at a safe altitude before the disk has made a full turn. The heads fly in the 'ground effect', with contours such that the faster the disk turns, carrying the air with it, the closer to the disk the airflow pushes them, which when balanced against the ground effect, results in a very consistent head flying height of a very few microns. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) I have defined the hundred per cent American as ninety-nine per cent an idiot. -- George Bernard Shaw -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
