PCIe and storage devices get connected

Mike Klempa, University of New Hampshire
EDN (January 17, 2014)

SSDs (solid-state drives) are rapidly becoming the storage method of choice. With this changing of the guard from hard-disk drives to SSDs, there is a need for different connections than are used for hard drives or peripherals to utilize the an SSD's full potential. The connector and protocols discussed here are the future for the storage industry.

PCIe (Peripheral Component Interconnect express) has become the dominant connection technology between computer motherboards and internal peripheral devices such as graphics cards. The current generation (PCIe Gen3) operates at 8GT/s/lane on up to 32 lanes. PCIe has broken into the storage world with the advent of SATA Express and, NVMe (Non-Volatile Memory Express), storage technologies that use the PCIe connectors and signaling.

As computers have become smaller such as Ultrathin notebooks or tablet PCs connectors for peripheral devices had to shrink to accommodate tighter spaces. The PCI-SIG developed the M.2 connector to meet this demand. The connector is 22mm wide and the length can vary to make the best use of the technology being employed over it. The size is a 43% reduction in size over the standard x4 lane PCIe connector.

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