Abstract: The preferred embodiment of present invention is directed to an improved method and system for buffering incoming/unsolicited data received by a host computer that is connected to a network such as a storage area network. Specifically, in a host computer system in which the main memory of the host server maintains a I/O control block command ring, and which a connective port (e.g., a host bus adaptor) is operatively coupled to the main memory for handling I/O commands received by and transmitted from the host server, a host buffer queue (HBQ) is maintained for storing a series of buffer descriptors retrievable by the port for writing incoming/unsolicited data to specific address locations within the main memory.

Abstract: A 32-word command IOCB format is disclosed. A conventional 8-word format is supported, although in both cases 32-word command IOCBs are used. When the conventional 8-word format is used, the host sets the LE bit=1 and writes a conventional 8-word command IOCB into words 0-7 of the 32-word command IOCB. The firmware performs a DMA operation and reads the LE bit. With the LE bit=1, the firmware knows to read only words 0-7. When the new 32-word format is used, the host sets the LE bit=0 and writes a 32-word IOCB command into the 32-word command IOCB, including command and response buffer pointers, one or more data buffer pointers, and perhaps the command buffer. The firmware performs a DMA operation and reads the LE bit. With the LE bit=0, the firmware knows to read all 32 words of the command IOCB.