Some time ago another manufacturer produced a HD that was high capacity and low cost. They took a 3.5" mechanism and jacked it up with 5.25" platters. It worked well, but was slow for small file sizes because of the not-so-fast track access time and a (relatively) low rotation speed. For large files the performance was good because it didn’t have to move to another track very often. I thought it was not as much capacity as it could have been because it was thinner than its half-height 5.25" form factor mounting. There was room for another platter or two in the mounting space.
Another HD I had at work 'way back in the early days was large for its day; it had something like eight platters in a full height 5.25" form factor. The neat idea in that one was that the spindle motor was inside the hub, not below the platters. That let them get more platters in the vertical space.
Now: What would be the capacity of a HD that used ALL the half-height 5.25" form factor, and had the motor in the hub? If they can make 4TB in a 3.5" form factor what could they do in a box the same size as a CD/DVD drive? 100T ??
