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 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 information 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 58.Fx 59releases prior to 2.1, the first found will be attached as 60.Em ch0 61and the next, 62.Em ch1 63etc. 64Beginning in 2.1 it is possible to specify what ch unit a device should 65come on line as; refer to 66.Xr scsi 4 67for details on kernel configuration. 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.Sh IOCTLS 77User mode programs communicate with the changer driver through a 78number of ioctls which are described below. Changer element addresses 79used in the communication between the kernel and the changer device are 80mapped to zero-based logical addresses. Element types are specified 81as follows: 82.Bl -tag -width CHET_MT 83.It Dv CHET_MT 84Medium transport element (picker). 85.It Dv CHET_ST 86Storage element (slot). 87.It Dv CHET_IE 88Import/export element (portal). 89.It Dv CHET_DT 90Data transfer element (drive). 91.El 92.Pp 93The following 94.Xr ioctl 2 95calls apply to the changer. 96They are defined 97in the header file 98.Aq Pa sys/chio.h . 99.Pp 100.Bl -tag -width CHIOEXCHANGE 101.It Dv CHIOMOVE 102.Pq Li "struct changer_move" 103Move a medium from one element to another (\fBMOVE MEDIUM\fR) using 104the current picker. The source and destination elements are specified 105in a changer_move structure, which includes at least the following 106fields: 107.Bd -literal -offset indent 108u_int cm_fromtype; /* element type to move from */ 109u_int cm_fromunit; /* logical unit of from element */ 110u_int cm_totype; /* element type to move to */ 111u_int cm_tounit; /* logical unit of to element */ 112u_int cm_flags; /* misc. flags */ 113.Ed 114If the \fBCM_INVERT\fR in the \fBcm_flags\fR field is set, the medium 115changer is instructed to flip the medium while moving it. 116.It Dv CHIOEXCHANGE 117.Pq Li "struct changer_exchange" 118Move the medium located in the source element to the first destination 119element, and move the medium that had been in the first destination 120element to the second destination element. In case of a simple 121exchange, the source and second destination elements should be the 122same. The current picker is used to perform the operation. The 123addresses of the affected elements is specified to the ioctl in a 124changer_exchange structure which includes at least the following 125fields: 126.Bd -literal -offset indent 127u_int ce_srctype; /* element type of source */ 128u_int ce_srcunit; /* logical unit of source */ 129u_int ce_fdsttype; /* element type of first destination */ 130u_int ce_fdstunit; /* logical unit of first destination */ 131u_int ce_sdsttype; /* element type of second destination */ 132u_int ce_sdstunit; /* logical unit of second destination */ 133u_int ce_flags; /* misc. flags */ 134.Ed 135In \fBce_flags\fR, \fBCM_INVERT1\fR and/or \fBCM_INVERT2\fR may be set 136to flip the first or second medium during the exchange operation, 137respectively. 138.Pp 139\fIThis operation is untested.\fR 140.It Dv CHIOPOSITION 141.Pq Li "struct changer_position" 142Position the current picker in front of the specified element. The 143element is specified with a changer_position structure, which includes 144at least the following elements: 145.Bd -literal -offset indent 146u_int cp_type; /* element type */ 147u_int cp_unit; /* logical unit of element */ 148u_int cp_flags; /* misc. flags */ 149.Ed 150The \fBcp_flags\fR field may be set to \fBCP_INVERT\fR to invert the 151picker during the operation. 152.It Dv CHIOGPICKER 153.Pq Li "int" 154Return the logical address of the current picker. 155.It Dv CHIOSPICKER 156.Pq Li "int" 157Select the picker specified by the given logical address. 158.It Dv CHIOGPARAMS 159.Pq Li "struct changer_params" 160Return the configuration parameters for the media changer. This ioctl 161fills the changer_params structure passed by the user with at least the 162following fields: 163.Bd -literal -offset indent 164u_int cp_npickers; /* number of pickers */ 165u_int cp_nslots; /* number of slots */ 166u_int cp_nportals; /* number of import/export portals */ 167u_int cp_ndrives; /* number of drives */ 168.Ed 169.Pp 170This call can be used by applications to query the dimensions of 171the jukebox before using the \fBCHIGSTATUS\fR 172ioctl to query the jukebox' status. 173.It Dv CHIOIELEM 174Perform the \fBINITIALIZE ELEMENT STATUS\fR call on the media changer 175device. This forces the media changer to update its internal status 176information with respect to loaded media. It also scans any barcode 177labels provided that it has a label reader. The 178.Nm 179driver's status is not affected by this call. 180.It Dv CHIOGSTATUS 181.Pq Li "struct changer_element_status_request" 182Perform the \fBREAD ELEMENT STATUS\fR call on the media changer 183device. This call reads the element status information of the media 184changer and converts it to an array of \fBchanger_element_status\fR 185structures. 186.Pp 187With each call to 188.Dv CHIOGSTATUS , 189the status of one or more elements of one type may be queried. 190.Pp 191The application passes a changer_element_status_request structure to the 192.Nm 193driver which contains the following fields: 194.Bd -literal -offset indent 195u_int cesr_element_type; 196u_int cesr_element_base; 197u_int cesr_element_count; 198u_int cesr_flags; 199struct changer_element_status *cesr_element_status; 200.Ed 201.Pp 202This structure is read by the driver to determine the type, logical 203base address and number of elements for which information is to be 204returned in the array of changer_element_status structures pointed to 205by the cesr_element_status field. The application must allocate enough 206memory for cesr_element_count status structures (see below). 207The cesr_flags can optionally be set to 208.Dv CESR_VOLTAGS 209to indicate that volume tag (bar code) information is to be read from 210the jukebox and returned. 211.Pp 212The cesr_element_base and cesr_element_count fields must be valid with 213respect to the physical configuration of the changer. If they are 214not, the 215.Dv CHIOGSTATUS 216ioctl returns the 217.Er EINVAL 218error code. 219.Pp 220The information about the elements is returned in an array of 221changer_element_status structures. This structure include at least 222the following fields: 223.Bd -literal -offset indent 224u_int ces_addr; /* element address in media changer */ 225u_char ces_flags; /* see CESTATUS definitions below */ 226u_char ces_sensecode; /* additional sense code for element */ 227u_char ces_sensequal; /* additional sense code qualifier */ 228u_char ces_invert; /* invert bit */ 229u_char ces_svalid; /* source address (ces_source) valid */ 230u_short ces_source; /* source address of medium */ 231changer_voltag_t ces_pvoltag; /* primary volume tag */ 232changer_voltag_t ces_avoltag; /* alternate volume tag */ 233u_char ces_idvalid; /* ces_scsi_id is valid */ 234u_char ces_scsi_id; /* SCSI id of element (if ces_idvalid is nonzero) */ 235u_char ces_lunvalid; /* ces_scsi_lun is valid */ 236u_char ces_scsi_lun; /* SCSI lun of element (if ces_lunvalid is nonzero) */ 237.Ed 238.Pp 239The ces_addr field contains the address of the element in the 240coordinate system of the media changer. It is not used by the driver, 241and should be used for diagnostic purposes only. 242.Pp 243The following flags are defined for the \fBces_flags\fR field: 244.Bl -tag -width CESTATUS_IMPEXP 245.It Dv CESTATUS_FULL 246A medium is present. 247.It Dv CESTATUS_IMPEXP 248The medium has been deposited by the operator (and not by a picker). 249.It Dv CESTATUS_EXCEPT 250The element is in an exceptional state (e.g. invalid barcode label, 251barcode not yet scanned). 252.It Dv CESTATUS_ACCESS 253The element is accessible by the picker. 254.It Dv CESTATUS_EXENAB 255The element supports medium export. 256.It Dv CESTATUS_INENAB 257The element supports medium import. 258.El 259.Pp 260Note that not all flags are valid for all element types. 261.El 262.Sh NOTES 263This version of the 264.Nm 265driver has been tested with a DEC TZ875 (5 slot, one DLT drive) and a 266and a Breece Hill Q47 (60 slot, four DLT drives, barcode reader). 267.Pp 268Many of the features the 269.Nm 270driver supports are not throughly tested due to the fact that the 271devices available for testing do not support the necessary commands. 272This is true for alternate volume tags, media flipping, import/export 273element handling, multiple picker operation and other things. 274.Sh AUTHORS 275.An -nosplit 276The 277.Nm 278driver was written by 279.An Jason R. Thorpe Aq thorpej@and.com 280for And Communications, 281.Pa 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 da 4 , 303.Xr sa 4 304.Sh HISTORY 305The 306.Nm 307driver appeared in 308.Bx 386 0.1 . 309