[TriLUG] OT: the optimum location for inner track/cylinder on rotating media?

[Joseph Mack NA3T]

On Wed, 12 Aug 2009, Joseph Mack NA3T wrote:

> The test of the theory (that the maximum is not used to 
> placate users) would be to measure r for a device that the 
> users can't see, like a floppy or hard disk. These should 
> all have r=R/2. I can't find any floppies to disassemble. 
> and I don't have any dead hard disks

for the floppy disk r=R/2
for the hard disk   r=R/3

the floppy fits the theory, while the hard disk doesn't. 
This is disturbing.

I now see that all disks have a region at the center of 
r=R/3 that isn't used. The vinyl record has a label, The cd 
doesn't use the center section at all. The hard and flopyy 
disks have a large hub (for the drive mechanism?). In that 
case the max area allowed for the constant linear velocity 
type platter is pi*R^2(1-1/9) rather than pi*R^2. This 
doesn't affect my theory that the optimum location for the 
inner cylinder on constant angular velocity platters is 
r=R/2.

Joe

-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!