CHIO(1)                    OpenBSD Reference Manual                    CHIO(1)

NAME
     chio - medium changer control utility

SYNOPSIS
     chio [-f changer] command [arg ...]

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.

     A medium changer apparatus is made up of elements.  There are five ele-
     ment types: picker (medium transport), slot (storage), portal (import/ex-
     port), drive (data transfer), and voltag (select by volume identifier).
     The voltag pseudo-element type allows the selection of tapes by their
     volume code, which is 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''.

     The following commands are supported:

     exchange src-ET src-EU dst1-ET dst1-EU [dst2-ET dst2-EU] [inv1] [inv2]
             Performs a media unit exchange operation.  The media unit in src-
             ET/src-EU is moved to dst1-ET/dst1-EU and the media unit previ-
             ously in dst1-ET/dst1-EU is moved to dst2-ET/dst2-EU.  In the
             case of a simple exchange, dst2-ET/dst2-EU is omitted and the
             values src-ET/src-EU are used in their place.  The optional modi-
             fiers inv1 and inv2 specify whether the media units are to be in-
             verted before insertion into dst1-ET/dst2-EU and dst2-ET/dst2-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.

     getpicker
             Report which picker unit the changer is currently configured to
             use.

     move from-ET from-EU to-ET to-EU [inv]
             Moves the media unit from from-ET/from-EU to to-ET/to-EU.  If the
             optional modifier inv is specified, the media unit will be in-
             verted before insertion.  If from-ET is a drive, chio will first
             attempt to open and perform an MTOFFL operation on the st(4) de-
             vice corresponding to from-EU.  By default, the st(4) device
             /dev/rstX is used, where X is the from-EU.  This mapping can be
             changed by using the chio.conf(5) file.

     params  Report the number of slots, drives, pickers, and portals in the
             changer, and which picker unit the changer is currently config-
             ured to use.

     position to-ET to-EU [inv]
             Position the picker in front of the element described by to-
             ET/to-EU.  If the optional modifier inv is specified, the media
             unit will be inverted before insertion.

             Note that not all changers behave as expected in response to this
             command.

     setpicker unit
             Configure the changer to use picker unit.

     status  [-vVa] [ET] Report the status of all elements in the changer.  If
             ET is specified, report the status of all elements of type ET.

             -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.

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

             The status bits output are defined as follows:

             FULL    Element contains a media unit.

             IMPEXP  Media was deposited into element by an outside human op-
                     erator.

             EXCEPT  Element is in an abnormal state.

             ACCESS  Media in this element is accessible by a picker.

             EXENAB  Element supports passing media (exporting) to an outside
                     human operator.

             INENAB  Element supports receiving media (importing) from an out-
                     side human operator.

ENVIRONMENT
     CHANGER  The default changer may be overridden by setting this environ-
              mental variable to the desired changer device.

FILES
     /dev/ch0          Default changer device.

     /etc/chio.conf    Optional configuration file to set up a non-default
                       mapping between st(4) devices and changer drives.

EXAMPLES
     Move the media in slot 3 (fourth slot) to drive 0 (first drive):

           # chio move slot 3 drive 0

     Move the media with volume tag 000007L2 to drive 1 (second drive):

           # chio move voltag 00007L2 drive 1

     Configure the changer to use picker 2 (third picker) for operations:

           # chio setpicker 2

SEE ALSO
     mt(1), ch(4), st(4), chio.conf(5)

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

OpenBSD 4.7                    November 2, 2007                              2
