DESCRIPTION

     The chio utility is used to control the operation of medium changers,
     such as those found in tape and optical disk jukeboxes.

     The options are as follows:

     -f changer
             Use the device changer rather than the default device /dev/ch0.

     The default changer may be overridden by setting the environment variable
     CHANGER to the desired changer device.

     A medium changer apparatus is made up of elements.  There are five ele-
     ment types: picker (medium transport), slot (storage), portal
     (import/export), drive (data transfer), and voltag (select by volume
     identifier).  The voltag pseudo-element type allows the selection of
     tapes by their volume tag (typically a barcode on the tape).

     In this command description, the shorthand ET will be used to represent
     an element type, and EU will be used to represent an element unit.  For
     example, to represent the first robotic arm in the changer, the ET would
     be ``picker'' and the EU would be ``0''.

SUPPORTED COMMANDS

     move <from ET> <from EU> <to ET> <to EU> [inv]
             Move the media unit from <from ET/EU> to <to ET/EU>.  If the
             optional modifier inv is specified, the media unit will be
             inverted before insertion.

     exchange <src ET> <src EU> <dst1 ET> <dst1 EU> [<dst2 ET> <dst2 ET>]
             [inv1] [inv2]
             Perform a media unit exchange operation.  The media unit in <src
             ET/EU> is moved to <dst1 ET/EU> and the media unit previously in
             <dst1 ET/EU> is moved to <dst2 ET/EU>.  In the case of a simple
             exchange, <dst2 ET/EU> is omitted and the values <src ET/EU> are
             used in their place.  The optional modifiers inv1 and inv2 spec-
             ify whether the media units are to be inverted before insertion
             into <dst1 ET/EU> and <dst2 ET/EU> respectively.

             Note that not all medium changers support the exchange operation;
             the changer must have multiple free pickers or emulate multiple
             free pickers with transient storage.

     return <from ET> <from EU>
             Return the media unit to its source element.  This command will
             query the status of the specified media unit, and will move it to
             the element specified in its source attribute.  This is a conve-
             nient way to return media from a drive or portal to its previous
             element in the changer.

     position <to ET> <to EU> [inv]

     setpicker <unit>
             Configure the changer to use picker <unit>.

     ielem [<timeout>]
             Perform an INITIALIZE ELEMENT STATUS operation on the changer.
             The optional <timeout> parameter may be given to specify a time-
             out in seconds for the operations.  This may be used if the oper-
             ation takes unusually long because of buggy firmware or the like.

     voltag [-fca] <ET> <EU> [<label>] [<serial>]
             Change volume tag for an element in the media changer.  This com-
             mand is only supported by few media changers.  If it is not sup-
             ported by a device, using this command will usually result in an
             "Invalid Field in CDB" error message on the console.

             If the -c flag is specified, the volume tag of the specified ele-
             ment is cleared.  If the -f flag is specified, the volume tag is
             superseded with the specified volume tag even if a volume tag is
             already defined for the element.  It is an error to not specify
             the -f flag when trying to set a label for an element which
             already has volume tag information defined.

             The command works with the primary volume tag or, if the -a flag
             is given, with the alternate volume tag.

     status [-vVsSbIa] [<type>]
             Report the status of all elements in the changer.  If <type> is
             specified, report the status of all elements of type <type>.

     -v      Print the primary volume tag for each loaded medium, if any.  The
             volume tag is printed as ``<LABEL:SERIAL>''.

     -V      Print the alternate volume tag for each loaded medium, if any.

     -s      Print the additional sense code and additional sense code quali-
             fier for each element.

     -S      Print the element source address for each element.

     -b      Print SCSI bus information for each element.  Note that this
             information is valid only for drives.

     -I      Print the internal element addresses for each element.  The
             internal element address is not normally used with this driver.
             It is reported for diagnostic purposes only.

     -a      Print all additional information (as in -vVsSba).

     The status bits are defined as follows:

     FULL    Element contains a media unit.
     /dev/ch0  default changer device

EXAMPLES

     chio move slot 3 drive 0
             Move the media in slot 3 (fourth slot) to drive 0 (first drive).

     chio move voltag VOLUME01 drive 0
             Move the media with the barcode VOLUME01 to drive 0 (first
             drive).

     chio return drive 0
             Remove the tape from drive 0 (first drive) and return it to its
             original location in the rack.

     chio setpicker 2
             Configure the changer to use picker 2 (third picker) for opera-
             tions.

SEE ALSO

     mt(1), mount(8)

AUTHORS

     The chio program and SCSI changer driver were written by Jason R. Thorpe
     <thorpej@and.com> for And Communications, http://www.and.com/.

     Additional work by Hans Huebner <hans@artcom.de> and Steve Gunn
     <csg@waterspout.com>.

BSD                              May 14, 1998                              BSD