[KLUG Members] re: Revolutionary CD Drives & Rotations Per

[Adam Tauno Williams]

>>I didn't realize that.  Thank you for correcting me.  It reminds me a 
>>bit of the really old drives (like 80 MEG capacity) that had several 
>>alues you could use for sectors per track, depending on whether the 
>>partition in question was inside, middle, or outside of the disk.  Do 
>>you have any idea how the ZBR knows where to put the data when the 
>>tracks are different sizes?  I can't see any way of doing it without 
>>some fairly complicated math.
>Seems odd.  Can't one use a simple table if one knows the size of the 
>disk and the distance from center or edge?

The algorythm used is in the drives firmware,  and would depend upon the OEM or 
even the model.  I suspect cheaper drives use a hash table and more expensive 
(the 73Gb SCSI drives and greater) do use a more "mathmatical" method, based 
upon drive specs I've downloaded from IBM.  I also suspect these 
methods/algorythms are encumbered by the copyright/patent on the drive 
firmware/mechanism, given that I've seen *zero* explicit documentation on how 
ZBR works on a given device.