1.\" $FreeBSD: src/share/man/man4/ch.4,v 1.18.2.7 2001/08/17 13:08:37 ru Exp $ 2.\" $DragonFly: src/share/man/man4/ch.4,v 1.4 2004/03/11 12:28:55 hmp Exp $ 3.\" Copyright (c) 1996 4.\" Julian Elischer <julian@FreeBSD.org>. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.Dd May 14, 1998 29.Dt CH 4 30.Os 31.Sh NAME 32.Nm ch 33.Nd SCSI media-changer (juke box) driver 34.Sh SYNOPSIS 35.Cd device ch 36.Cd device ch1 target 4 unit 0 37.Sh DESCRIPTION 38The 39.Xr ch 40driver provides support for a 41.Em SCSI 42media changer. 43It allows many slots of media to be multiplexed between 44a number of drives. The changer device may optionally be equipped 45with a bar code reader, which reads label informationen attached to 46the media. 47.Pp 48A SCSI adapter must also be separately configured into the system 49before a SCSI changer can be configured. 50.Pp 51As the SCSI adapter is probed during boot, the 52.Em SCSI 53bus is scanned for devices. 54Any devices found which answer as 'Changer' 55type devices will be 'attached' to the 56.Nm 57driver. 58It is possible to specify what 59.Nm 60unit a device should 61come on line as; refer to 62.Xr scsi 4 63for details on kernel configuration. 64.Sh KERNEL CONFIGURATION 65In configuring, if an optional 66.Ar count 67is given in the specification, that number of SCSI media changers 68are configured; Most storage for them is allocated only when found 69so a large number of configured devices is cheap. 70(once the first 71has included the driver). 72.Sh IOCTLS 73User mode programs communicate with the changer driver through a 74number of ioctls which are described below. 75Changer element addresses 76used in the communcation between the kernel and the changer device are 77mapped to zero-based logical addresses. 78Element types are specified as follows: 79.Bl -tag -width CHET_MT 80.It Dv CHET_MT 81Medium transport element (picker). 82.It Dv CHET_ST 83Storage element (slot). 84.It Dv CHET_IE 85Import/export element (portal). 86.It Dv CHET_DT 87Data transfer element (drive). 88.El 89.Pp 90The following 91.Xr ioctl 2 92calls apply to the changer. 93They are defined 94in the header file 95.Aq Pa sys/chio.h . 96.Pp 97.Bl -tag -width CHIOEXCHANGE 98.It Dv CHIOMOVE 99.Pq Vt "struct changer_move" 100Move a medium from one element to another 101.Pq Sy "MOVE MEDIUM" 102using the current picker. 103The source and destination elements are specified 104in a changer_move structure, which includes at least the following 105fields: 106.Bd -literal -offset indent 107u_int cm_fromtype; /* element type to move from */ 108u_int cm_fromunit; /* logical unit of from element */ 109u_int cm_totype; /* element type to move to */ 110u_int cm_tounit; /* logical unit of to element */ 111u_int cm_flags; /* misc. flags */ 112.Ed 113If the 114.Dv CM_INVERT 115in the 116.Va cm_flags 117field is set, the medium 118changer is instructed to flip the medium while moving it. 119.It Dv CHIOEXCHANGE 120.Pq Vt "struct changer_exchange" 121Move the medium located in the source element to the first destination 122element, and move the medium that had been in the first destination 123element to the second destination element. 124In case of a simple 125exchange, the source and second destination elements should be the 126same. 127The current picker is used to perform the operation. 128The addresses of the affected elements is specified to the ioctl in a 129.Vt changer_exchange 130structure which includes at least the following 131fields: 132.Bd -literal -offset indent 133u_int ce_srctype; /* element type of source */ 134u_int ce_srcunit; /* logical unit of source */ 135u_int ce_fdsttype; /* element type of first destination */ 136u_int ce_fdstunit; /* logical unit of first destination */ 137u_int ce_sdsttype; /* element type of second destination */ 138u_int ce_sdstunit; /* logical unit of second destination */ 139u_int ce_flags; /* misc. flags */ 140.Ed 141In 142.Va ce_flags , 143.Dv CM_INVERT1 144and/or 145.Dv CM_INVERT2 146may be set 147to flip the first or second medium during the exchange operation, 148respectively. 149.Pp 150.Em This operation is untested . 151.It Dv CHIOPOSITION 152.Pq Vt "struct changer_position" 153Position the current picker in front of the specified element. 154The element is specified with a changer_position structure, which includes 155at least the following elements: 156.Bd -literal -offset indent 157u_int cp_type; /* element type */ 158u_int cp_unit; /* logical unit of element */ 159u_int cp_flags; /* misc. flags */ 160.Ed 161The 162.Va cp_flags 163field may be set to 164.Dv CP_INVERT 165to invert the picker during the operation. 166.It Dv CHIOGPICKER 167.Pq Vt int 168Return the logical address of the current picker. 169.It Dv CHIOSPICKER 170.Pq Vt int 171Select the picker specified by the given logical address. 172.It Dv CHIOGPARAMS 173.Pq Vt "struct changer_params" 174Return the configuration parameters for the media changer. 175This ioctl 176fills the changer_params structure passed by the user with at least the 177following fields: 178.Bd -literal -offset indent 179u_int cp_npickers; /* number of pickers */ 180u_int cp_nslots; /* number of slots */ 181u_int cp_nportals; /* number of import/export portals */ 182u_int cp_ndrives; /* number of drives */ 183.Ed 184.Pp 185This call can be used by applications to query the dimensions of 186the jukebox before using the 187.Dv CHIGSTATUS 188ioctl to query the jukebox' status. 189.It Dv CHIOIELEM 190Perform the 191.Sy INITIALIZE ELEMENT STATUS 192call on the media changer device. 193This forces the media changer to update its internal status 194information with respect to loaded media. 195It also scans any barcode labels provided that it has a label reader. 196The 197.Nm 198driver's status is not affected by this call. 199.It Dv CHIOGSTATUS 200.Pq Vt "struct changer_element_status_request" 201Perform the 202.Sy READ ELEMENT STATUS 203call on the media changer device. 204This call reads the element status information of the media 205changer and converts it to an array of 206.Vt changer_element_status 207structures. 208.Pp 209With each call to 210.Dv CHIOGSTATUS , 211the status of one or more elements of one type may be queried. 212.Pp 213The application passes a 214.Vt changer_element_status_request 215structure to the 216.Nm 217driver which contains the following fields: 218.Bd -literal -offset indent 219u_int cesr_element_type; 220u_int cesr_element_base; 221u_int cesr_element_count; 222u_int cesr_flags; 223struct changer_element_status *cesr_element_status; 224.Ed 225.Pp 226This structure is read by the driver to determine the type, logical 227base address and number of elements for which information is to be 228returned in the array of 229.Vt changer_element_status 230structures pointed to by the 231.Va cesr_element_status field . 232The application must allocate enough 233memory for 234.Va cesr_element_count 235status structures (see below). 236The 237.Va cesr_flags 238can optionally be set to 239.Dv CESR_VOLTAGS 240to indicate that volume tag (bar code) information is to be read from 241the jukebox and returned. 242.Pp 243The 244.Va cesr_element_base 245and 246.Va cesr_element_count 247fields must be valid with respect to the physical configuration of the changer. 248If they are not, the 249.Dv CHIOGSTATUS 250ioctl returns the 251.Er EINVAL 252error code. 253.Pp 254The information about the elements is returned in an array of 255.Vt changer_element_status 256structures. 257This structure include at least the following fields: 258.Bd -literal -offset indent 259u_int ces_addr; /* element address in media changer */ 260u_char ces_flags; /* see CESTATUS definitions below */ 261u_char ces_sensecode; /* additional sense code for element */ 262u_char ces_sensequal; /* additional sense code qualifier */ 263u_char ces_invert; /* invert bit */ 264u_char ces_svalid; /* source address (ces_source) valid */ 265u_short ces_source; /* source address of medium */ 266changer_voltag_t ces_pvoltag; /* primary volume tag */ 267changer_voltag_t ces_avoltag; /* alternate volume tag */ 268u_char ces_idvalid; /* ces_scsi_id is valid */ 269u_char ces_scsi_id; /* SCSI id of element (if ces_idvalid is nonzero) */ 270u_char ces_lunvalid; /* ces_scsi_lun is valid */ 271u_char ces_scsi_lun; /* SCSI lun of elemtne (if ces_lunvalid is nonzero) */ 272.Ed 273.Pp 274The 275.Va ces_addr 276field contains the address of the element in the 277coordinate system of the media changer. 278It is not used by the driver, 279and should be used for diagnostic purposes only. 280.Pp 281The following flags are defined for the 282.Va ces_flags 283field: 284.Bl -tag -width CESTATUS_IMPEXP 285.It Dv CESTATUS_FULL 286A medium is present. 287.It Dv CESTATUS_IMPEXP 288The medium has been deposited by the operator (and not by a picker). 289.It Dv CESTATUS_EXCEPT 290The element is in an exceptional state (e.g. invalid barcode label, 291barcode not yet scanned). 292.It Dv CESTATUS_ACCESS 293The element is accessible by the picker. 294.It Dv CESTATUS_EXENAB 295The element supports medium export. 296.It Dv CESTATUS_INENAB 297The element supports medium import. 298.El 299.Pp 300Note that not all flags are valid for all element types. 301.El 302.Sh NOTES 303This version of the 304.Nm 305driver has been tested with a DEC TZ875 (5 slot, one DLT drive) and a 306and a Breece Hill Q47 (60 slot, four DLT drives, barcode reader). 307.Pp 308Many of the features the 309.Nm 310driver supports are not thouroghly tested due to the fact that the 311devices available for testing do not support the necessary commands. 312This is true for alternate volume tags, media flipping, import/export 313element handling, multiple picker operation and other things. 314.Sh AUTHORS 315.An -nosplit 316The 317.Nm 318driver was written by 319.An Jason R. Thorpe Aq thorpej@and.com 320for And Communications, 321.Pa http://www.and.com/ . 322It was added to the system by 323.An Stefan Grefen Aq grefen@goofy.zdv.uni-mainz.de 324who apparently had such a device. 325It was ported to CAM by 326.An Kenneth Merry Aq ken@FreeBSD.org . 327It was updated to support volume tags by 328.An Hans Huebner Aq hans@artcom.de . 329.Sh FILES 330.Bl -tag -width /dev/ch[0-9] -compact 331.It Pa /dev/ch[0-9] 332device entries 333.El 334.Sh DIAGNOSTICS 335If the media changer does not support features requested by the 336.Nm 337driver, it will produce both console error messages and failure return 338codes to the ioctls described here. 339.Sh SEE ALSO 340.Xr chio 1 , 341.Xr cd 4 , 342.Xr da 4 , 343.Xr sa 4 344.Sh HISTORY 345The 346.Nm 347driver appeared in 348.Bx 386 0.1 . 349