What if the bar were able to travel linerarly via a voice coil, and had hundreds of heads, but the bar was able to shift in a linear fashion only about a micron back and forth in increments of thousandths of a micron.
Wouldn't that get you to your millions of heads of effective track coverage, without all the complexity of having to move two or three different hinges on several different actuators sweeping the entire arc? Naively speaking it seems like you could mount such a bar even closer to the surface of the track since there is no chance of a head crash, as it could be supported at both ends of its mounting.
Surely the entire armature that moves an articulated set of actuator assemblies plus the head itself would be heavier and more cumbersome and failure-proneto move than a linearly-fixed rail.
Obviously someone has thought of this before me so there's a good reason for it, but track density alone can't be it.
What problem does your proposal potentially solve?
A strip of heads that move in unison won't be able to operate in parallel, for the same reason that on real hard drives heads serving different platters cannot operate in parallel without being mounted on independent actuators. So it seems like your suggestion only reduces the distance that any given head needs to move, at the cost of greatly increasing the mass of heads+wiring that needs to be positioned quickly and accurately. You've seriously inflated cost for no gain in bandwidth and likely no gain in latency (and even if everything worked out in favor, it couldn't do anything to improve rotational latency).
I don't know I keep getting answers to different proposals than the one that I have made, all with a significant detail changed so that the answer makes sense and the proposal sounds absurd.
In this case, I don't know how the impression could be gained that I was suggesting mounting 100 or so individual assemblies of the very same read write head currently used on mechanical drives, each with its own separate wiring harness.
Obviously, yes that would substantially increase the cost and the mass and everything else, you're right. Thanks for setting me straight about the impracticality of very different solution than the one I described, which suggested the heads could be manufactured as a single integrated unit, the way every other matrix of active elements (OLED displays, memory cells, someone else mentioned mems, etc.) is made, which might require two additional wires for selection signalling, if that, depending on what could be multiplexed. In exchange for this weight and complexity you get rid of one, possibly two extra servo joints, one possibly two extra armatures, plus all the wiring and additional control logic required for positioning this very delicate articulated assembly.
Now, if this array cannot be manufactured because no current solid state process exists that can reproduce the characteristics of a wound coil, duplicated a hundred times in a linear array of cells on silicon or some other substrate, that's an obstacle I can reason about and accept as a plausible dead end.
Wouldn't that get you to your millions of heads of effective track coverage, without all the complexity of having to move two or three different hinges on several different actuators sweeping the entire arc? Naively speaking it seems like you could mount such a bar even closer to the surface of the track since there is no chance of a head crash, as it could be supported at both ends of its mounting.
Surely the entire armature that moves an articulated set of actuator assemblies plus the head itself would be heavier and more cumbersome and failure-proneto move than a linearly-fixed rail.
Obviously someone has thought of this before me so there's a good reason for it, but track density alone can't be it.