chio - medium changer control utility
chio [-f changer] command arg1 arg2 [arg3 [...]]
The chio utility is used to control the operation of medium
such as those found in tape and optical disk jukeboxes.
The options are as follows:
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 four element
types: picker (medium transport), slot (storage),
and drive (data transfer). 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''.
# chio move <from ET> <from EU> <to ET> <to EU> [inv]
Moves the media unit from <from ET/EU> to <to ET/EU>. If
modifier inv is specified, the media unit will be inverted
# chio exchange <src ET> <src EU> <dst1 ET> <dst1 EU> [<dst2
EU>] [inv1] [inv2]
Performs a media unit exchange operation. The media unit in
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.
modifiers inv1 and inv2 specify 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
with transient storage.
# chio position <to ET> <to EU> [inv]
Position the picker in front of the element described by <to
the optional modifier inv is specified, the media unit will
Note that not all changers behave as expected in response to
# chio params
Report the number of slots, drives, pickers, and portals in
and which picker unit the changer is currently configured to
# chio getpicker
Report which picker unit the changer is currently configured
# chio setpicker <unit>
Configure the changer to use picker <unit>.
# chio status [<type>]
Report the status of all elements in the changer. If <type>
report the status of all elements of type <type>.
The status bits are defined as follows:
FULL Element contains a media unit.
IMPEXP Media was deposited into element by an outside human
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
INENAB Element supports receiving media (importing) from an
/dev/ch0 default changer device
# chio move slot 3 drive 0
Moves the media in slot 3 (fourth slot) to drive 0 (first
# chio setpicker 2
Configures the changer to use picker 2 (third picker) for
The chio program and SCSI changer driver were written by Jason R. Thorpe
<email@example.com> for And Communications
OpenBSD 3.6 April 2, 1996
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