HDDs Limited by Form Factor
Well, how to cram more bits in a square inch on an HDD platter has been going on for a long time. HAMR and MAMR HDDs are the next generations as PMR HDDs reach the limits imposed by physics. SMR HDDs are an error-prone aberration. Helium filled HDDs are more of a gimmick. Helium atoms themselves are very hard to contain for a long time. The real problem is HDDs are constrained by their form factor. NAND flash in all its various form factors is more flexible and extensible. Caging electrons is going to prove more productive than manipulating magnetic domains. NAND flash already dominates the 3TB and under storage drive market. NAND flash prices are at or slightly below the $0.10 per GB price. HDDs are living on borrowed time. They weigh too much, use too much space and consume too much electricity.