Legacy-compatible extended command input-output control block

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 - of the 32-word command IOCB...

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Bibliographic Details
Main Authors Nicolson, IV, Alexander, Scherer, Gregory John
Format Patent
LanguageEnglish
Published 05.01.2010
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Summary: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 - 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 -. 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.