I was review technical specifications for a Hitachi Disk drive E7K1000. First, I assume that 1D, 2D & 3D refer to the number of disks/platters that are in the physical drive. Is this correct? Assuming that is correct, then as the number of platters increases in the drive the average seek time goes down. This seems opposite to conventional thinking. Normally as you add additional heads (weight) this increases the inertia of the head assembly and it takes longer to move the head from one place to another. If you have ever had to work with any positioning system, you always want the positioner to be as light as possible to have the fastest switching time.
Can someone explain why they show a decreased seek time with more platters?
Link to specification PDF: http://www.hitachigst.com/tech/techlib.nsf/techdocs/CF6C5D47F5BCE65B862574C1007E985D/$file/DS_CS_7K1000.B_Spec_rev3.01.pdf