That article provides the physical characteristics of a bunch of drives across several decades. The newest there is a 5TB drive that has tracks 85nm wide and bits 17nm long, so each bit is a rectangle with a 5:1 aspect ratio. The oldest is a 44.7MB drive with tracks 40um wide and bits 2.6um long, for an even more extreme ~15:1 ratio, but all the drives follow this pattern: the bits are much wider than they are long. The ratio for floppy disks is even more extreme; its calculation is left as an exercise for the reader.
Of course this doesn't change your argument that millions of heads would be necessary, at sub-micron spacing, to say nothing of how alignment could be maintained with continual thermal expansion and contraction.
They are actually not: https://news.ycombinator.com/item?id=39428728
That article provides the physical characteristics of a bunch of drives across several decades. The newest there is a 5TB drive that has tracks 85nm wide and bits 17nm long, so each bit is a rectangle with a 5:1 aspect ratio. The oldest is a 44.7MB drive with tracks 40um wide and bits 2.6um long, for an even more extreme ~15:1 ratio, but all the drives follow this pattern: the bits are much wider than they are long. The ratio for floppy disks is even more extreme; its calculation is left as an exercise for the reader.
Of course this doesn't change your argument that millions of heads would be necessary, at sub-micron spacing, to say nothing of how alignment could be maintained with continual thermal expansion and contraction.