Interface for heterogeneous PCI-e storage devices

A storage device interface, comprising:

• a plurality of Peripheral Component Interconnect Express (PCIe) device request engines to receive Input/Output (I/O) commands formatted for a respective one of a plurality of PCIe storage device communication standards;
• a plurality of PCIe device completion engines to receive notifications of command completions by a plurality of PCIe storage devices that communicate using said plurality of PCIe storage device communication standards, said plurality of PCIe device request engines and said PCIe device completion engines to operate concurrently to process received I/O commands and received command completions;
• and
• a queue configuration for each of said plurality of PCIe storage devices, wherein said queue configuration includes an indicator of a device type associated with each of said plurality of PCIe storage devices, wherein said indicator of said device type is used to determine a respective format of said I/O commands formatted for a respective one of a plurality of PCIe storage device communication standards, and wherein said indicator of said device type is used to select a one of said plurality of PCIe device request engines to transfer a corresponding I/O command to a corresponding one of said plurality of PCIe storage devices.