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32 .Nd SCSI media-changer (juke box) driver
35 .Cd device ch1 target 4 unit 0
39 driver provides support for a
42 It allows many slots of media to be multiplexed between
43 a number of drives. The changer device may optionally be equipped
44 with a bar code reader, which reads label informationen attached to
47 A SCSI adapter must also be separately configured into the system
48 before a SCSI changer can be configured.
50 As the SCSI adapter is probed during boot, the
52 bus is scanned for devices.
53 Any devices found which answer as 'Changer'
54 type devices will be 'attached' to the
57 It is possible to specify what
60 come on line as; refer to
62 for details on kernel configuration.
63 .Sh KERNEL CONFIGURATION
64 In configuring, if an optional
66 is given in the specification, that number of SCSI media changers
67 are configured; Most storage for them is allocated only when found
68 so a large number of configured devices is cheap.
70 has included the driver).
72 User mode programs communicate with the changer driver through a
73 number of ioctls which are described below.
74 Changer element addresses
75 used in the communication between the kernel and the changer device are
76 mapped to zero-based logical addresses.
77 Element types are specified as follows:
78 .Bl -tag -width CHET_MT
80 Medium transport element (picker).
82 Storage element (slot).
84 Import/export element (portal).
86 Data transfer element (drive).
91 calls apply to the changer.
95 .Bl -tag -width ".Dv CHIOEXCHANGE"
97 .Pq Vt "struct changer_move"
98 Move a medium from one element to another
100 using the current picker.
101 The source and destination elements are specified
102 in a changer_move structure, which includes at least the following
104 .Bd -literal -offset indent
105 u_int cm_fromtype; /* element type to move from */
106 u_int cm_fromunit; /* logical unit of from element */
107 u_int cm_totype; /* element type to move to */
108 u_int cm_tounit; /* logical unit of to element */
109 u_int cm_flags; /* misc. flags */
115 field is set, the medium
116 changer is instructed to flip the medium while moving it.
118 .Pq Vt "struct changer_exchange"
119 Move the medium located in the source element to the first destination
120 element, and move the medium that had been in the first destination
121 element to the second destination element.
123 exchange, the source and second destination elements should be the
125 The current picker is used to perform the operation.
126 The addresses of the affected elements is specified to the ioctl in a
128 structure which includes at least the following
130 .Bd -literal -offset indent
131 u_int ce_srctype; /* element type of source */
132 u_int ce_srcunit; /* logical unit of source */
133 u_int ce_fdsttype; /* element type of first destination */
134 u_int ce_fdstunit; /* logical unit of first destination */
135 u_int ce_sdsttype; /* element type of second destination */
136 u_int ce_sdstunit; /* logical unit of second destination */
137 u_int ce_flags; /* misc. flags */
145 to flip the first or second medium during the exchange operation,
148 .Em This operation is untested .
150 .Pq Vt "struct changer_position"
151 Position the current picker in front of the specified element.
152 The element is specified with a changer_position structure, which includes
153 at least the following elements:
154 .Bd -literal -offset indent
155 u_int cp_type; /* element type */
156 u_int cp_unit; /* logical unit of element */
157 u_int cp_flags; /* misc. flags */
163 to invert the picker during the operation.
166 Return the logical address of the current picker.
169 Select the picker specified by the given logical address.
171 .Pq Vt "struct changer_params"
172 Return the configuration parameters for the media changer.
174 fills the changer_params structure passed by the user with at least the
176 .Bd -literal -offset indent
177 u_int cp_npickers; /* number of pickers */
178 u_int cp_nslots; /* number of slots */
179 u_int cp_nportals; /* number of import/export portals */
180 u_int cp_ndrives; /* number of drives */
183 This call can be used by applications to query the dimensions of
184 the jukebox before using the
186 ioctl to query the jukebox' status.
189 .Sy INITIALIZE ELEMENT STATUS
190 call on the media changer device.
191 This forces the media changer to update its internal status
192 information with respect to loaded media.
193 It also scans any barcode labels provided that it has a label reader.
196 driver's status is not affected by this call.
198 .Pq Vt "struct changer_element_status_request"
200 .Sy READ ELEMENT STATUS
201 call on the media changer device.
202 This call reads the element status information of the media
203 changer and converts it to an array of
204 .Vt changer_element_status
209 the status of one or more elements of one type may be queried.
211 The application passes a
212 .Vt changer_element_status_request
215 driver which contains the following fields:
216 .Bd -literal -offset indent
217 u_int cesr_element_type;
218 u_int cesr_element_base;
219 u_int cesr_element_count;
221 struct changer_element_status *cesr_element_status;
224 This structure is read by the driver to determine the type, logical
225 base address and number of elements for which information is to be
226 returned in the array of
227 .Vt changer_element_status
228 structures pointed to by the
229 .Va cesr_element_status field .
230 The application must allocate enough
232 .Va cesr_element_count
233 status structures (see below).
236 can optionally be set to
238 to indicate that volume tag (bar code) information is to be read from
239 the jukebox and returned.
242 .Va cesr_element_base
244 .Va cesr_element_count
245 fields must be valid with respect to the physical configuration of the changer.
252 The information about the elements is returned in an array of
253 .Vt changer_element_status
255 This structure include at least the following fields:
256 .Bd -literal -offset indent
257 u_int ces_addr; /* element address in media changer */
258 u_char ces_flags; /* see CESTATUS definitions below */
259 u_char ces_sensecode; /* additional sense code for element */
260 u_char ces_sensequal; /* additional sense code qualifier */
261 u_char ces_invert; /* invert bit */
262 u_char ces_svalid; /* source address (ces_source) valid */
263 u_short ces_source; /* source address of medium */
264 changer_voltag_t ces_pvoltag; /* primary volume tag */
265 changer_voltag_t ces_avoltag; /* alternate volume tag */
266 u_char ces_idvalid; /* ces_scsi_id is valid */
267 u_char ces_scsi_id; /* SCSI id of element (if ces_idvalid is nonzero) */
268 u_char ces_lunvalid; /* ces_scsi_lun is valid */
269 u_char ces_scsi_lun; /* SCSI lun of elemtne (if ces_lunvalid is nonzero) */
274 field contains the address of the element in the
275 coordinate system of the media changer.
276 It is not used by the driver,
277 and should be used for diagnostic purposes only.
279 The following flags are defined for the
282 .Bl -tag -width CES_STATUS_IMPEXP
283 .It Dv CES_STATUS_FULL
285 .It Dv CES_STATUS_IMPEXP
286 The medium has been deposited by the operator (and not by a picker).
287 .It Dv CES_STATUS_EXCEPT
288 The element is in an exceptional state (e.g. invalid barcode label,
289 barcode not yet scanned).
290 .It Dv CES_STATUS_ACCESS
291 The element is accessible by the picker.
292 .It Dv CES_STATUS_EXENAB
293 The element supports medium export.
294 .It Dv CES_STATUS_INENAB
295 The element supports medium import.
298 Note that not all flags are valid for all element types.
303 driver has been tested with a DEC TZ875 (5 slot, one DLT drive) and a
304 and a Breece Hill Q47 (60 slot, four DLT drives, barcode reader).
306 Many of the features the
308 driver supports are not thoroughly tested due to the fact that the
309 devices available for testing do not support the necessary commands.
310 This is true for alternate volume tags, media flipping, import/export
311 element handling, multiple picker operation and other things.
313 .Bl -tag -width /dev/ch[0-9] -compact
318 If the media changer does not support features requested by the
320 driver, it will produce both console error messages and failure return
321 codes to the ioctls described here.
336 driver was written by
337 .An Jason R. Thorpe Aq Mt thorpej@and.com
338 for And Communications,
339 .Pa http://www.and.com/ .
340 It was added to the system by
341 .An Stefan Grefen Aq Mt grefen@goofy.zdv.uni-mainz.de
342 who apparently had such a device.
343 It was ported to CAM by
344 .An Kenneth Merry Aq Mt ken@FreeBSD.org .
345 It was updated to support volume tags by
346 .An Hans Huebner Aq Mt hans@artcom.de .