International Blinking Pattern Interpretation

[1] SGPIO has been adopted across the storage industry, and has in large replaced proprietary protocols such as SCSI Enclosure Services (SES) and SAF-TE.

Note, however, that both IBPI and the underlying SGPIO are documenting common practice rather than providing requirements; the entire changelog for version 0.4 of IPBI is "Text changes made to identify this specification as one alternative, rather than the only one.

The state of a drive or slot is determined by the host bus adapter, and is typically transmitted to the backplane through SGPIO-signals on a cable.

In a typical system architecture, the host bus adapter (HBA) connects to a backplane through a 4× iPass[clarification needed] cable.

SGPIO is typically used in conjunction with SAS or SATA cables, where each physical port is attached to a single disk drive.

The figure below shows the relationship between SClock, SLoad and the two data bits named SDataOut and SDataIn.

The original SGPIO stream was intended for a low-cost implementation, and is limited to the capability of representing activity, locate, and fail LEDs.

With the advent of SAS/SATA hard drives, backplanes typically do not vary much from low to high end systems, except the addition of an extra physical port in the case of SAS.

This resulted in the IBPI specification, which uses blinking frequencies of bits in the SGPIO stream to represent additional states of drives.