Enterprise customers looking to assemble storage systems have a number of interfaces available for connecting drives, but the physical form factor of the devices generally follows one of four forms, traditionally designed for client machines: the familiar 2.5" or 3.5" cuboids, M.2 gumsticks, or PCIe cards. Intel is adding a new option that the company says is tailored to the density and connectivity needs of datacenters, the "ruler" form factor.
On first glance, the ruler form factor looks something like a super-sized M.2 card with its long, slender profile measuring 12.8" (32.5 cm) long and 1.5" (3.9 cm) wide with a slightly narrower edge connector. Each ruler SSD is a separate module with room for several times more storage chips than conventional drive form factors, resulting in increased capacity and greater parallelism. Intel says the form factor should let manufacturers cram 1 PB of flash storage into a 1U server chassis.
According to Anandtech, ruler drives use a SFF-TA-1002 "Gen-Z" connector. That Gen-Z interface supports four- and eight-lane PCIe 3.1 interfaces for up to 7.88 GB/s of bidirectional bandwidth. The connector itself has more pins than an M.2 connector. The extra pins are used for enterprise features like SMBus management and charging power loss protection capacitors. The drives are supplied +12 V DC.
The site goes on to say that the form factor has been in service at some of Intel's select partners for the last eight months and that the company's DC P4500 drives will be the first available through the normal channels in the new form factor. Drives based on Intel's 3D XPoint products will also follow in the future.