mechanics

HDD & SSD Combined Into One

Wafer Scale HDDThe SSD Guy has often explained to readers that the storage industry is caught between two alternatives:  fast and costly, or cheap and slow.  This is the key difference between SSDs and HDDs.  I have recently learned of a new secret government research effort, code named “SiliDisk,” that will provide the best of both worlds by marrying flash memory with the mechanics of an HDD.

The approach is incredibly ingenious, while remaining deceptively simple: All that is required is to replace the disks in an HDD with the wafers used to manufacture NAND flash.  Both are round, so there’s little engineering effort to switch from a magnetic disk to a flash wafer.

The NAND flash on the wafer is almost completely standard.  The only two changes are that the chips aren’t scribed or sawn apart, saving a small sum, but a hole must be etched through the center (which can be seen in the photo below) offsetting this savings.  The HDD mechanisms are unchanged with one exception: While today’s HDDs are largely manufactured using 2.5″ and 3.5″ platters (65mm & 90mm), NAND flash is exclusively produced on 300mm wafers.  This means that Continue reading