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CISS(4)		       FreeBSD Kernel Interfaces Manual		       CISS(4)

     ciss -- Common Interface for SCSI-3 Support driver.

     For one or	more adapters:
     device scbus
     device ciss

     The ciss driver claims to provide a common	interface between generic SCSI
     transports	and intelligent	host adapters.

     The ciss driver supports CISS as defined in the document entitled ``CISS
     Command Interface for SCSI-3 Support Open Specification'',	Version	1.04,
     Valence Number 1, dated 20001127, produced	by Compaq Computer Corpora-

     We	provide	a shim layer between the ciss interface	and CAM, offloading
     most of the queueing and being-a-disk chores onto CAM.  Entry to the
     driver is via the PCI bus attachment ciss_probe, ciss_attach, etc and via
     the CAM interface ciss_cam_action,	and ciss_cam_poll.  The	Compaq ciss
     adapters require faked responses to get reasonable	behavior out of	them.
     In	addition, the ciss command set is by no	means adequate to support the
     functionality of a	RAID controller, and thus the supported	Compaq
     adapters utilize portions of the control protocol from earlier Compaq
     adapter families.

     Currently ciss only supports the ``simple'' transport layer over PCI.
     This interface (ab)uses the I2O register set (specifically	the post
     queues) to	exchange commands with the adapter.  Other interfaces are
     available,	but we are not supposed	to know	about them, and	it is dubious
     whether they would	provide	major performance improvements except under
     extreme load.

     Non disk devices (such as internal	DATs and devices attached to the
     external SCSI bus)	are not	yet supported.

     Supported controllers include:

     Compaq Smart Array	5300
     Compaq Smart Array	532
     Compaq Smart Array	5i

     cam(4), pass(4), xpt(4), camcontrol(8),

     ``CISS Command Interface for SCSI-3 Support Open Specification, Version
     1.04,'' Valence Number 1, dated 20001127, produced	by Compaq Computer

     The ciss driver was written by Mike Smith <>.  This
     manual page is based on his comments and was written by

FreeBSD	11.1		       December	29, 2002		  FreeBSD 11.1


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