Could someone please clarify the statement below? I see the words "adhesion" and "stick" associated with the air moving with the disk platter. Then, we are told this is NOT caused by friction between the air and the platter. Pray tell, what physical effect IS responsible? I can assure you that a smooth, even very smooth platter will drag along the air adjacent to it, due to skin friction. The air moving with the platter is typical of what is called a boundary layer. I suspect that this layer is laminar for a smooth platter. Rougher platters may not work as well because they may lead to boundary layer transition to turbulent flow, which, on the small scales we are talking about, may give the heads a relatively rougher ride. Certainly they would cause more drag, consuming more power.
Thanks, from a puzzled aerodynamicist, Bob -------------------- Begin Original Message -------------------- Message text written by INTERNET:[EMAIL PROTECTED] "The adhesion effect discovered by Tesla is what allows hard drives to work. Air sticks to the surface of the platters and is carried around with them. The heads have a slope on their leading edge so they can "surf" on top of the layer of air. This effect is NOT caused by friction between the air and the platters. The smoother the platters are, the better they work. Hard drives cannot work in a vacuum because there's no air for the heads to fly on. (And the volatile components in the bearing lube would gass off.) Any hard drive used on a spacecraft must be in a container or other sealed space with air or some sort of gas." -------------------- End Original Message -------------------- -- Vintage Macs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac <http://lowendmac.com/lists/support.html> Vintage Macs list info: <http://lowendmac.com/lists/vintagemacs.shtml> The FAQ: <http://macfaq.org/> Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/vintage.macs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
