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CISS(4)			 BSD Kernel Interfaces Manual		       CISS(4)

     ciss -- Common Interface for SCSI-3 Support driver

     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 2000/11/27, produced by Compaq Computer Corpora-

     We	provide	a shim layer between the ciss interface	and CAM(4), 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 ex-
     ternal SCSI bus) are supported as normal CAM devices provided that	they
     are exported by the controller firmware and are not marked	as being
     masked.  Masked devices can be exposed by setting the
     hw.ciss.expose_hidden_physical tunable to non-zero	at boot	time.  Direct
     Access devices (such as disk drives) are only exposed as pass(4) devices.
     Hot-insertion and removal of devices is supported but a bus rescan	might
     be	necessary.

     Controllers supported by the ciss driver include:

     o	 Compaq	Smart Array 5300
     o	 Compaq	Smart Array 532
     o	 Compaq	Smart Array 5i
     o	 HP Smart Array	5312
     o	 HP Smart Array	6i
     o	 HP Smart Array	641
     o	 HP Smart Array	642
     o	 HP Smart Array	6400
     o	 HP Smart Array	6400 EM
     o	 HP Smart Array	6422
     o	 HP Smart Array	V100
     o	 HP Modular Smart Array	20 (MSA20)
     o	 HP Modular Smart Array	500 (MSA500)

     cam(4), pass(4), xpt(4), loader.conf(5), camcontrol(8)

     CISS Command Interface for	SCSI-3 Support Open Specification, Version
     1.04, Valence Number 1, Compaq Computer Corporation, 2000/11/27.

     The ciss driver was written by Mike Smith <>.

     This manual page is based on his comments and was written by Tom Rhodes

BSD				August 3, 2004				   BSD


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