CHIO(1)

NAME
chio - medium changer control utility

SYNOPSIS
chio [-f changer] command arg1 arg2 [ arg3 [...]]

DESCRIPTION
chio 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 four element types: picker (medium transport), slot (storage), portal (import/export), 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”.

SUPPORTED COMMANDS
chio move from ET from EU to ET to EU [inv]

Moves 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.

chio exchange src ET src EU dst1 ET dst1 EU [dst2 ET dst2 ET] [inv1] [inv2]

Performs 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 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 free pickers with transient storage.

chio position to ET to EU [inv]

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

Note that not all changers behave as expected when issued this command.

chio params

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

chio getpicker

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

chio setpicker unit

Configure the changer to use picker unit.

chio status [type [unit [count]]] [voltags]

Report the status of all elements in the changer. If type is specified, 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 operator.

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 outside human operator.

If the element is a drive, the device name of the drive will be reported if it is available.

If the [voltags] option is specified, primary and alternate volume tag information will be reported, if available.

If the previous location of the media is available, it will also be reported.

chio ielem

Perform an INITIALIZE ELEMENT STATUS operation on the changer.

chio cdlu sub-command slot

This command is provided for controlling CD-ROM changer mechanisms which cannot use the standard changer control interface. ATAPI CD-ROM changers fall into this category. There are 3 sub-commands:

load
    Loads the media from the specified slot into the CD-ROM drive.

unload
    Unloads the media from the CD-ROM drive and returns it to the specified slot.

abort
    Aborts any pending load or unload operation.

FILES
/dev/ch0 - default changer device

EXAMPLES
    chio -f /dev/ch0 move slot 3 drive 0

Moves the media in slot 3 (fourth slot) to drive 0 (first drive).

    chio setpicker 2

Configures the changer to use picker 2 (third picker) for operations.

    chio -f /dev/cd0a cdlu load 1

Loads the media from slot (second slot) into the CD-ROM drive.

    chio -f /dev/ch1 status

Returns status of all elements in the second changer.

SEE ALSO
mt(1), mount(8)

AUTHORS
The chio program and SCSI changer driver were originally written by Jason R. Thorpe for And Communications: http://www.and.com/. Additional development was done by Jason R. Thorpe for the Numerical Aerospace Simulation Facility, NASA Ames Research Center.