1.\" $FreeBSD$ 2.\" Copyright (c) 1996 3.\" Julian Elischer <julian@freebsd.org>. All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.Dd May 14, 1998 28.Dt CH 4 29.Os FreeBSD 30.Sh NAME 31.Nm ch 32.Nd SCSI media-changer (juke box) driver 33.Sh SYNOPSIS 34.Cd device ch 35.Cd device ch1 target 4 unit 0 36.Sh DESCRIPTION 37The 38.Xr ch 39driver provides support for a 40.Em SCSI 41media changer. 42It allows many slots of media to be multiplexed between 43a number of drives. The changer device may optionally be equipped 44with a bar code reader, which reads label informationen attached to 45the media. 46.Pp 47A SCSI adapter must also be separately configured into the system 48before a SCSI changer can be configured. 49.Pp 50As the SCSI adapter is probed during boot, the 51.Em SCSI 52bus is scanned for devices. 53Any devices found which answer as 'Changer' 54type devices will be 'attached' to the 55.Nm 56driver. 57In FreeBSD releases prior to 2.1, the first found will be attached as 58.Em ch0 59and the next, 60.Em ch1 61etc. 62Beginning in 2.1 it is possible to specify what ch unit a device should 63come on line as; refer to 64.Xr scsi 4 65for details on kernel configuration. 66.Pp 67 68.Sh KERNEL CONFIGURATION 69In configuring, if an optional 70.Ar count 71is given in the specification, that number of SCSI media changers 72are configured; Most storage for them is allocated only when found 73so a large number of configured devices is cheap. 74(once the first 75has included the driver). 76 77.Pp 78.Sh IOCTLS 79User mode programs communicate with the changer driver through a 80number of ioctls which are described below. Changer element addresses 81used in the communcation between the kernel and the changer device are 82mapped to zero-based logical addresses. Element types are specified 83as follows: 84.Bl -tag -width CHET_MT 85.It Dv CHET_MT 86Medium transport element (picker). 87.It Dv CHET_ST 88Storage element (slot). 89.It Dv CHET_IE 90Import/export element (portal). 91.It Dv CHET_DT 92Data transfer element (drive). 93.El 94.Pp 95The following 96.Xr ioctl 2 97calls apply to the changer. 98They are defined 99in the header file 100.Aq Pa sys/chio.h . 101.Pp 102.Bl -tag -width CHIOEXCHANGE 103.It Dv CHIOMOVE 104.Pq Li "struct changer_move" 105Move a medium from one element to another (\fBMOVE MEDIUM\fR) using 106the current picker. The source and destination elements are specified 107in a changer_move structure, which includes at least the following 108fields: 109.Bd -literal -offset indent 110u_int cm_fromtype; /* element type to move from */ 111u_int cm_fromunit; /* logical unit of from element */ 112u_int cm_totype; /* element type to move to */ 113u_int cm_tounit; /* logical unit of to element */ 114u_int cm_flags; /* misc. flags */ 115.Ed 116If the \fBCM_INVERT\fR in the \fBcm_flags\fR field is set, the medium 117changer is instructed to flip the medium while moving it. 118.It Dv CHIOEXCHANGE 119.Pq Li "struct changer_exchange" 120Move the medium located in the source element to the first destination 121element, and move the medium that had been in the first destination 122element to the second destination element. In case of a simple 123exchange, the source and second destination elements should be the 124same. The current picker is used to perform the operation. The 125addresses of the affected elements is specified to the ioctl in a 126changer_exchange structure which includes at least the following 127fields: 128.Bd -literal -offset indent 129u_int ce_srctype; /* element type of source */ 130u_int ce_srcunit; /* logical unit of source */ 131u_int ce_fdsttype; /* element type of first destination */ 132u_int ce_fdstunit; /* logical unit of first destination */ 133u_int ce_sdsttype; /* element type of second destination */ 134u_int ce_sdstunit; /* logical unit of second destination */ 135u_int ce_flags; /* misc. flags */ 136.Ed 137In \fBce_flags\fR, \fBCM_INVERT1\fR and/or \fBCM_INVERT2\fR may be set 138to flip the first or second medium during the exchange operation, 139respectively. 140.Pp 141\fIThis operation is untested.\fR 142.It Dv CHIOPOSITION 143.Pq Li "struct changer_position" 144Position the current picker in front of the specified element. The 145element is specified with a changer_position structure, which includes 146at least the following elements: 147.Bd -literal -offset indent 148u_int cp_type; /* element type */ 149u_int cp_unit; /* logical unit of element */ 150u_int cp_flags; /* misc. flags */ 151.Ed 152The \fBcp_flags\fR field may be set to \fBCP_INVERT\fR to invert the 153picker during the operation. 154.It Dv CHIOGPICKER 155.Pq Li "int" 156Return the logical address of the current picker. 157.It Dv CHIOSPICKER 158.Pq Li "int" 159Select the picker specified by the given logical address. 160.It Dv CHIOGPARAMS 161.Pq Li "struct changer_params" 162Return the configuration parameters for the media changer. This ioctl 163fills the changer_params structure passed by the user with at least the 164following fields: 165.Bd -literal -offset indent 166u_int cp_npickers; /* number of pickers */ 167u_int cp_nslots; /* number of slots */ 168u_int cp_nportals; /* number of import/export portals */ 169u_int cp_ndrives; /* number of drives */ 170 171.Ed 172This call can be used by applications to query the dimensions of 173the jukebox before using the \fBCHIGSTATUS\fR 174ioctl to query the jukebox' status. 175.It Dv CHIOIELEM 176Perform the \fBINITIALIZE ELEMENT STATUS\fR call on the media changer 177device. This forces the media changer to update it's internal status 178information with respect to loaded media. It also scans any barcode 179labels provided that it has a label reader. The 180.Nm 181driver's status is not affected by this call. 182.It Dv CHIOGSTATUS 183.Pq Li "struct changer_element_status_request" 184Perform the \fBREAD ELEMENT STATUS\fR call on the media changer 185device. This call reads the element status information of the media 186changer and converts it to an array of \fBchanger_element_status\fR 187structures. 188.Pp 189With each call to 190.Dv CHIOGSTATUS 191, the status of one or more elements of one type may be queried. 192.Pp 193The application passes a changer_element_status_request structure to the 194.Nm 195driver which contains the following fields: 196.Bd -literal -offset indent 197u_int cesr_element_type; 198u_int cesr_element_base; 199u_int cesr_element_count; 200u_int cesr_flags; 201struct changer_element_status *cesr_element_status; 202 203.Ed 204This structure is read by the driver to determine the type, logical 205base address and number of elements for which information is to be 206returned in the array of changer_element_status structures pointed to 207by the cesr_element_status field. The application must allocate enough 208memory for cesr_element_count status structures (see below). 209The cesr_flags can optionally be set to 210.Dv CESR_VOLTAGS 211to indicate that volume tag (bar code) information is to be read from 212the jukebox and returned. 213.Pp 214The cesr_element_base and cesr_element_count fields must be valid with 215respect to the physical configuration of the changer. If they are 216not, the 217.Dv CHIOGSTATUS 218ioctl returns the 219.Er EINVAL 220error code. 221.Pp 222The information about the elements is returned in an array of 223changer_element_status structures. This structure include at least 224the following fields: 225.Bd -literal -offset indent 226u_int ces_addr; /* element address in media changer */ 227u_char ces_flags; /* see CESTATUS definitions below */ 228u_char ces_sensecode; /* additional sense code for element */ 229u_char ces_sensequal; /* additional sense code qualifier */ 230u_char ces_invert; /* invert bit */ 231u_char ces_svalid; /* source address (ces_source) valid */ 232u_short ces_source; /* source address of medium */ 233changer_voltag_t ces_pvoltag; /* primary volume tag */ 234changer_voltag_t ces_avoltag; /* alternate volume tag */ 235u_char ces_idvalid; /* ces_scsi_id is valid */ 236u_char ces_scsi_id; /* SCSI id of element (if ces_idvalid is nonzero) */ 237u_char ces_lunvalid; /* ces_scsi_lun is valid */ 238u_char ces_scsi_lun; /* SCSI lun of elemtne (if ces_lunvalid is nonzero) */ 239 240.Ed 241The ces_addr field contains the address of the element in the 242coordinate system of the media changer. It is not used by the driver, 243and should be used for diagnostic purposes only. 244.Pp 245The following flags are defined for the \fBces_flags\fR field: 246.Bl -tag -width CESTATUS_IMPEXP 247.It Dv CESTATUS_FULL 248A medium is present. 249.It Dv CESTATUS_IMPEXP 250The medium has been deposited by the operator (and not by a picker). 251.It Dv CESTATUS_EXCEPT 252The element is in an exceptional state (e.g. invalid barcode label, 253barcode not yet scanned). 254.It Dv CESTATUS_ACCESS 255The element is accessible by the picker. 256.It Dv CESTATUS_EXENAB 257The element supports medium export. 258.It Dv CESTATUS_INENAB 259The element supports medium import. 260.El 261.Pp 262Note that not all flags are valid for all element types. 263.El 264.Sh NOTES 265This version of the 266.Nm 267driver has been tested with a DEC TZ875 (5 slot, one DLT drive) and a 268and a Breece Hill Q47 (60 slot, four DLT drives, barcode reader). 269.Pp 270Many of the features the 271.Nm 272driver supports are not thouroghly tested due to the fact that the 273devices available for testing do not support the necessary commands. 274This is true for alternate volume tags, media flipping, import/export 275element handling, multiple picker operation and other things. 276.Sh AUTHORS 277The 278.Nm 279driver was written by 280.An Jason R. Thorpe Aq thorpej@and.com 281for And Communications, http://www.and.com/. 282It was added to the system by 283.An Stefan Grefen Aq grefen@goofy.zdv.uni-mainz.de 284who apparently had such a device. 285It was ported to CAM by 286.An Kenneth Merry Aq ken@FreeBSD.org . 287It was updated to support volume tags by 288.An Hans Huebner Aq hans@artcom.de . 289.Sh FILES 290.Bl -tag -width /dev/ch[0-9] -compact 291.It Pa /dev/ch[0-9] 292device entries 293.El 294.Sh DIAGNOSTICS 295If the media changer does not support features requested by the 296.Nm 297driver, it will produce both console error messages and failure return 298codes to the ioctls described here. 299.Sh SEE ALSO 300.Xr chio 1 , 301.Xr cd 4 , 302.Xr sd 4 , 303.Xr st 4 304.Sh HISTORY 305The 306.Nm 307driver appeared in 386BSD 0.1. 308