304 lines
11 KiB
Groff
304 lines
11 KiB
Groff
.\" $Id: ch.4,v 1.11 1997/06/02 21:01:00 max Exp $
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.\" Copyright (c) 1996
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.\" Julian Elischer <julian@freebsd.org>. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\"
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.Dd May 14, 1998
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.Dt CH 4
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.Os FreeBSD
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.Sh NAME
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.Nm ch
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.Nd SCSI media-changer (juke box) driver
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.Sh SYNOPSIS
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.Cd device ch
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.Cd device ch1 target 4 lun 0
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.Sh DESCRIPTION
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The
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.Xr ch
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driver provides support for a
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.Em SCSI
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media changer. It allows many slots of media to be multiplexed between
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a number of drives. The changer device may optionally be equipped
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with a bar code reader, which reads label informationen attached to
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the media.
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.Pp
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A SCSI adapter must also be separately configured into the system
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before a SCSI changer can be configured.
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.Pp
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As the SCSI adapter is probed during boot, the
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.Em SCSI
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bus is scanned for devices. Any devices found which answer as 'Changer'
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type devices will be 'attached' to the
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.Nm
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driver.
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In FreeBSD releases prior to 2.1, the first found will be attached as
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.Em ch0
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and the next,
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.Em ch1
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etc.
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Beginning in 2.1 it is possible to specify what ch unit a device should
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come on line as; refer to
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.Xr scsi 4
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for details on kernel configuration.
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.Pp
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.Sh KERNEL CONFIGURATION
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In configuring, if an optional
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.Ar count
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is given in the specification, that number of SCSI media changers
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are configured; Most storage for them is allocated only when found
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so a large number of configured devices is cheap. (once the first
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has included the driver).
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.Pp
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.Sh IOCTLS
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User mode programs communicate with the changer driver through a
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number of ioctls which are described below. Changer element addresses
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used in the communcation between the kernel and the changer device are
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mapped to zero-based logical addresses. Element types are specified
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as follows:
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.Bl -tag -width CHET_MT
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.It Dv CHET_MT
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Medium transport element (picker).
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.It Dv CHET_ST
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Storage element (slot).
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.It Dv CHET_IE
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Import/export element (portal).
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.It Dv CHET_DT
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Data transfer element (drive).
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.El
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.Pp
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The following
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.Xr ioctl 2
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calls apply to the changer. They are defined in
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in the header file
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.Aq Pa sys/chio.h .
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.Pp
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.Bl -tag -width CHIOEXCHANGE
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.It Dv CHIOMOVE
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.Pq Li "struct changer_move"
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Move a medium from one element to another (\fBMOVE MEDIUM\fR) using
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the current picker. The source and destination elements are specified
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in a changer_move structure, which includes at least the following
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fields:
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.Bd -literal -offset indent
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u_int cm_fromtype; /* element type to move from */
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u_int cm_fromunit; /* logical unit of from element */
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u_int cm_totype; /* element type to move to */
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u_int cm_tounit; /* logical unit of to element */
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u_int cm_flags; /* misc. flags */
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.Ed
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If the \fBCM_INVERT\fR in the \fBcm_flags\fR field is set, the medium
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changer is instructed to flip the medium while moving it.
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.It Dv CHIOEXCHANGE
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.Pq Li "struct changer_exchange"
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Move the medium located in the source element to the first destination
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element, and move the medium that had been in the first destination
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element to the second destination element. In case of a simple
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exchange, the source and second destination elements should be the
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same. The current picker is used to perform the operation. The
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addresses of the affected elements is specified to the ioctl in a
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changer_exchange structure which includes at least the following
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fields:
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.Bd -literal -offset indent
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u_int ce_srctype; /* element type of source */
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u_int ce_srcunit; /* logical unit of source */
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u_int ce_fdsttype; /* element type of first destination */
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u_int ce_fdstunit; /* logical unit of first destination */
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u_int ce_sdsttype; /* element type of second destination */
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u_int ce_sdstunit; /* logical unit of second destination */
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u_int ce_flags; /* misc. flags */
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.Ed
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In \fBce_flags\fR, \fBCM_INVERT1\fR and/or \fBCM_INVERT2\fR may be set
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to flip the first or second medium during the exchange operation,
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respectively.
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.Pp
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\fIThis operation is untested.\fR
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.It Dv CHIOPOSITION
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.Pq Li "struct changer_position"
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Position the current picker in front of the specified element. The
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element is specified with a changer_position structure, which includes
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at least the following elements:
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.Bd -literal -offset indent
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u_int cp_type; /* element type */
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u_int cp_unit; /* logical unit of element */
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u_int cp_flags; /* misc. flags */
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.Ed
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The \fBcp_flags\fR field may be set to \fBCP_INVERT\fR to invert the
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picker during the operation.
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.It Dv CHIOGPICKER
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.Pq Li "int"
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Return the logical address of the current picker.
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.It Dv CHIOSPICKER
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.Pq Li "int"
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Select the picker specified by the given logical address.
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.It Dv CHIOGPARAMS
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.Pq Li "struct changer_params"
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Return the configuration parameters for the media changer. This ioctl
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fills the changer_params structure passed by the user with at least the
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following fields:
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.Bd -literal -offset indent
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u_int cp_npickers; /* number of pickers */
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u_int cp_nslots; /* number of slots */
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u_int cp_nportals; /* number of import/export portals */
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u_int cp_ndrives; /* number of drives */
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.Ed
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This call can be used by applications to query the dimensions of
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the jukebox before using the \fBCHIGSTATUS\fR
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ioctl to query the jukebox' status.
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.It Dv CHIOIELEM
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Perform the \fBINITIALIZE ELEMENT STATUS\fR call on the media changer
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device. This forces the media changer to update it's internal status
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information with respect to loaded media. It also scans any barcode
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labels provided that it has a label reader. The
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.Nm
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driver's status is not affected by this call.
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.It Dv CHIOGSTATUS
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.Pq Li "struct changer_element_status_request"
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Perform the \fBREAD ELEMENT STATUS\fR call on the media changer
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device. This call reads the element status information of the media
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changer and converts it to an array of \fBchanger_element_status\fR
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structures.
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.Pp
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With each call to
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.Dv CHIOGSTATUS
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, the status of one or more elements of one type may be queried.
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.Pp
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The application passes a changer_element_status_request structure to the
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.Nm
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driver which contains the following fields:
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.Bd -literal -offset indent
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u_int cesr_element_type;
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u_int cesr_element_base;
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u_int cesr_element_count;
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u_int cesr_flags;
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struct changer_element_status *cesr_element_status;
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.Ed
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This structure is read by the driver to determine the type, logical
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base address and number of elements for which information is to be
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returned in the array of changer_element_status structures pointed to
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by the cesr_element_status field. The application must allocate enough
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memory for cesr_element_count status structures (see below).
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The cesr_flags can optionally be set to
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.Dv CESR_VOLTAGS
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to indicate that volume tag (bar code) information is to be read from
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the jukebox and returned.
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.Pp
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The cesr_element_base and cesr_element_count fields must be valid with
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respect to the physical configuration of the changer. If they are
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not, the
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.Dv CHIOGSTATUS
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ioctl returns the
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.Er EINVAL
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error code.
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.Pp
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The information about the elements is returned in an array of
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changer_element_status structures. This structure include at least
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the following fields:
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.Bd -literal -offset indent
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u_int ces_addr; /* element address in media changer */
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u_char ces_flags; /* see CESTATUS definitions below */
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u_char ces_sensecode; /* additional sense code for element */
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u_char ces_sensequal; /* additional sense code qualifier */
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u_char ces_invert; /* invert bit */
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u_char ces_svalid; /* source address (ces_source) valid */
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u_short ces_source; /* source address of medium */
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changer_voltag_t ces_pvoltag; /* primary volume tag */
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changer_voltag_t ces_avoltag; /* alternate volume tag */
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u_char ces_idvalid; /* ces_scsi_id is valid */
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u_char ces_scsi_id; /* SCSI id of element (if ces_idvalid is nonzero) */
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u_char ces_lunvalid; /* ces_scsi_lun is valid */
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u_char ces_scsi_lun; /* SCSI lun of elemtne (if ces_lunvalid is nonzero) */
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.Ed
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The ces_addr field contains the address of the element in the
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coordinate system of the media changer. It is not used by the driver,
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and should be used for diagnostic purposes only.
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.Pp
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The following flags are defined for the \fBces_flags\fR field:
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.Bl -tag -width CESTATUS_IMPEXP
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.It Dv CESTATUS_FULL
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A medium is present.
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.It Dv CESTATUS_IMPEXP
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The medium has been deposited by the operator (and not by a picker).
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.It Dv CESTATUS_EXCEPT
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The element is in an exceptional state (e.g. invalid barcode label,
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barcode not yet scanned).
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.It Dv CESTATUS_ACCESS
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The element is accessible by the picker.
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.It Dv CESTATUS_EXENAB
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The element supports medium export.
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.It Dv CESTATUS_INENAB
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The element supports medium import.
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.El
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.Pp
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Note that not all flags are valid for all element types.
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.El
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.Sh NOTES
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This version of the
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.Nm
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driver has been tested with a DEC TZ875 (5 slot, one DLT drive) and a
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and a Breece Hill Q47 (60 slot, four DLT drives, barcode reader).
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.Pp
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Many of the features the
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.Nm
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driver supports are not thouroghly tested due to the fact that the
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devices available for testing do not support the necessary commands.
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This is true for alternate volume tags, media flipping, import/export
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element handling, multiple picker operation and other things.
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.Sh AUTHORS
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The
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.Nm
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driver was written by
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.An Jason R. Thorpe Aq thorpej@and.com
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for And Communications, http://www.and.com/.
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It was added to the system by
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.An Stefan Grefen Aq grefen@goofy.zdv.uni-mainz.de
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who apparently had such a device.
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It was ported to CAM by
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.An Kenneth Merry Aq ken@FreeBSD.ORG .
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It was updated to support volume tags by
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.An Hans Huebner Aq hans@artcom.de .
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.Sh FILES
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.Bl -tag -width /dev/ch[0-9] -compact
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.It Pa /dev/ch[0-9]
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device entries
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.El
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.Sh DIAGNOSTICS
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If the media changer does not support features requested by the
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.Nm
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driver, it will produce both console error messages and failure return
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codes to the ioctls described here.
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.Sh SEE ALSO
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.Xr chio 1 ,
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.Xr cd 4 ,
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.Xr sd 4 ,
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.Xr st 4
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.Sh HISTORY
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The
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.Nm
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driver appeared in 386BSD 0.1.
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