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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
     Command Interface for SCSI-3 Support Open Specification, Version 1.04,
     Valence Number 1, dated 2000/11/27, produced by Compaq Computer Corpora-
     tion.

     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
     external 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.

HARDWARE

     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)

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 5.4			August 3, 2004			   FreeBSD 5.4

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