pt(4) [freebsd man page]

PT(4)							   BSD Kernel Interfaces Manual 						     PT(4)

NAME

     pt -- SCSI processor type driver

SYNOPSIS

     device pt

DESCRIPTION

     The pt driver provides support for a SCSI processor type device.  These are usually scanners and other devices using the SCSI link as a com-
     munication interface with device specific commands embedded in the data stream.

     A SCSI adapter must be separately configured into the system before this driver can be used.

     This device supports read(2) and write(2), and the ioctl(2) calls described below.

IOCTLS

     The following ioctl(2) calls are supported by the pt driver.  They are defined in the header file <sys/ptio.h>.

     PTIOCGETTIMEOUT  This ioctl allows userland applications to fetch the current pt driver read and write timeout.  The value returned is in
		      seconds.

     PTIOCSETTIMEOUT  This ioctl allows userland applications to set the current pt driver read and write timeouts.  The value should be in sec-
		      onds.

FILES

     /dev/ptN	 the Nth processor device.

SEE ALSO

     cam(4)

HISTORY

     The pt driver appeared in FreeBSD 2.1.

BSD
								   March 2, 1995							       BSD

PASS(4) 						   BSD Kernel Interfaces Manual 						   PASS(4)

NAME

     pass -- CAM application passthrough driver

SYNOPSIS

     device pass

DESCRIPTION

     The pass driver provides a way for userland applications to issue CAM CCBs to the kernel.

     Since the pass driver allows direct access to the CAM subsystem, system administrators should exercise caution when granting access to this
     driver.  If used improperly, this driver can allow userland applications to crash a machine or cause data loss.

     The pass driver attaches to every SCSI device found in the system.  Since it attaches to every device, it provides a generic means of access-
     ing SCSI devices, and allows the user to access devices which have no "standard" peripheral driver associated with them.

KERNEL CONFIGURATION

     It is only necessary to configure one pass device in the kernel; pass devices are automatically allocated as SCSI devices are found.

IOCTLS

     CAMIOCOMMAND     This ioctl takes most kinds of CAM CCBs and passes them through to the CAM transport layer for action.  Note that some CCB
		      types are not allowed through the passthrough device, and must be sent through the xpt(4) device instead.  Some examples of
		      xpt-only CCBs are XPT_SCAN_BUS, XPT_DEV_MATCH, XPT_RESET_BUS, XPT_SCAN_LUN, XPT_ENG_INQ, and XPT_ENG_EXEC.  These CCB types
		      have various attributes that make it illogical or impossible to service them through the passthrough interface.

     CAMGETPASSTHRU   This ioctl takes an XPT_GDEVLIST CCB, and returns the passthrough device corresponding to the device in question.  Although
		      this ioctl is available through the pass driver, it is of limited use, since the caller must already know that the device in
		      question is a passthrough device if they are issuing this ioctl.	It is probably more useful to issue this ioctl through the
		      xpt(4) device.

FILES

     /dev/passn  Character device nodes for the pass driver.  There should be one of these for each device accessed through the CAM subsystem.

DIAGNOSTICS

     None.

SEE ALSO

     cam(3), cam_cdbparse(3), cam(4), xpt(4), camcontrol(8)

HISTORY

     The CAM passthrough driver first appeared in FreeBSD 3.0.

AUTHORS

     Kenneth Merry <ken@FreeBSD.org>

BUGS

     It might be nice to have a way to asynchronously send CCBs through the passthrough driver.  This would probably require some sort of
     read/write interface or an asynchronous ioctl interface.

BSD
								 October 10, 1998							       BSD