I'm guessing that the status quo exists and that my suggestion is inherently flawed because of the precision required to maintain the head at 10 nm above the surface and as such letting fluid dynamics wrestle with gravity might do the trick for you (given that you can make the spindles in a precise manner that the forces cancel out in a way that ensures that the head is exactly at the desired distance above the drive)
That leads to another thought, would the following conjecture be in the realm of possibility? Imagine that you have coated the disk with mystery thing X - which is an etched semiconductor that does something very magical. When an incident beam of light strikes a point on the coating, it releases electrons, which are then controlled through magical mechanism Y etched on X to create a magnetic field that flips the bit. If you do this then you can remove all of this stuff and it might lead to some gains.
In terms of the mystery thing 'x', most of what you might think of as candidate materials have been tried. The challenge is to reliably (well at least reasonably so) flip the state of a bit on the substrate in about a microsecond. And do that as cheaply as possible.
It is exceptionally challenging engineering.
>>> It is exceptionally challenging engineering. <<<
It's also very beautiful... When you look at something like that it's a bit like looking at a work of art - I don't know how to explain it but it is awe inspiring. I wonder how people end up working on such things... How do you get to the point where you can raise your sleeves and create a system as beautiful as this?
Keep in mind that the size of a magnetic grain (which stores 1 bit, roughly) is about 8nm. Compare that to the current cutting edge lithography scale of 14nm, which is the size of the semiconductor 'wires'.
Thus, a bit is smaller than the size even of the wires in any semiconductor circuit we can build, which means a system as you describe would have much lower storage density.
The head is only "flying" relative to the platter. A hard drive works pretty much like you describe -- a short stack of fast-spinning platters and a read/write head on a swing arm that pivots back and forth over the platters.
A pic: http://msuweb.montclair.edu/~maciakl/blog/img/hd.jpg
They are child's play to take apart (http://turmon.org/Images/celeste-disk.jpg)
The read/write arm needs speed and extremely fine-tuned movement that can't be had from a mechanical actuator. See: https://www.youtube.com/watch?v=Wiy_eHdj8kg
Disk heads "fly" above the surface of the disk on a cushion of gas that's pulled under the head by the spinning disk. If there isn't enough gas pressure inside the disk enclosure, this method of locating the heads won't work. Wikipedia actually says:
If the air density is too low, then there is not enough lift for the flying head, so the head gets too close to the disk, and there is a risk of head crashes and data loss. Specially manufactured sealed and pressurized disks are needed for reliable high-altitude operation, above about 3,000 m (9,800 ft).
http://en.wikipedia.org/wiki/Hard_disk_drive#Integrity_and_f...
Atmospheric pressure on the top and bottom faces of a 3.5" drive case (~22 square inches) is in the neighborhood of 300 pounds each, and there's still more on the front, back, and sides. A square box of thin aluminum is probably not a great starting point for building a pressure vessel. If the box is filled with a gas at close to atmospheric pressure, you don't have to worry about it.
Helium's specific heat is five times that of air, so it probably offers better heat conduction than air at 1/7th atmospheric pressure would.