Lucas123 writes: With the introduction of 3D or stacked NAND flash memory, non-volatile memory has for the first time surpassed that of hard disk drives in density. This year, Micron revealed it had demonstrated areal densities in its laboratories of up to 2.77 terabits per square inch (Tbpsi) for its 3D NAND. That compares with the densest HDDs of about 1.3Tbpsi. While NAND flash may have surpassed hard drives in density, it doesn't mean the medium has reached price parity with HDDs — nor will it anytime soon. One roadblock to price parity is the cost of revamping existing or building new 3D NAND fabrication plant, which far exceeds that of hard drive manufacturing facilities, according to market research firm Coughlin Associates. HDD makers are also preparing to launch even denser products using technologies such as heat assisted magnetic recording.