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CISS(4) 		     Kernel Interfaces Manual			 CISS(4)

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

SYNOPSIS
     device scbus
     device ciss

DESCRIPTION
     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 Com-
     mand Interface for SCSI-3 Support Open Specification, Version 1.04, Valence
     Number 1, dated 2000/11/27, produced by Compaq Computer Corporation.

     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 fami-
     lies.

     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 exter-
     nal 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 dri-
     ves) are only exposed as pass(4) devices.	Hot-insertion and removal of de-
     vices is supported but a bus rescan might be necessary.

HARDWARE
     Controllers supported by the ciss driver include:

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

SEE ALSO
     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.

AUTHORS
     The ciss driver was written by Mike Smith <msmith@FreeBSD.org>.

     This manual page is based on his comments and was	written  by  Tom  Rhodes
     <trhodes@FreeBSD.org>.

FreeBSD 5.3			 August 3, 2004 			 CISS(4)

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