On Oct 23, 2008, at 2:24 PM, Dan wrote:
> Each set of heads is on an arm, whoze positioning is *critical* -- > the head has to line up exactly over the track, or it fails to read > or write the data correctly. It's done with a step motor and > springs. It's done by a voice-coil "motor", not a stepper motor, and no springs. Positioning of a head above a track is accomplished by feedback control, in which the track data itself is used to position the head. This characteristic is necessary because a voice-coil "motor" has an infinite number of steps (that is, it has NO steps at all). > As the drive ages, metal fatigues. The lifetime of the materials employed far exceeds the expected lifetime of the drive by many times. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed Low End Mac's G3-5 List, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/g3-5-list?hl=en Low End Mac RSS feed at feed://lowendmac.com/feed.xml -~----------~----~----~----~------~----~------~--~---
