juke -- operate a SCSI media changer


juke operation [device]


The juke utility sends a command to a SCSI media changer (or ``juke box'') device to move data media between its various elements. The device argument defaults to /dev/Sjk0, the first media changer defined in the system.

Supported operations are:

List the internal elements of the media changer. (The SCSI-2 media changer model defines four physical parts, or ``elements'', for juke box devices. The physical configuration of these elements should be defined in the hardware manual supplied with the device.)

The elem operation displays elements using the following codes:

Data transfer element; an embedded SCSI peripheral device (such as a tape or CD-ROM drive) which is capable of reading or writing a data medium. Medium changer devices normally contain one or more data transfer elements.

Import/export element; a special storage location where a human operator or another media changer can insert or remove a data medium using an access door or external loader mechanism. A media transport element moves data media between an import/export element and storage elements and data transfer elements which are usually not accessible externally. A media changer device may have zero or more import/export elements.

Medium transport element; a robotic mechanism which moves data media between storage elements, data transfer elements, and import/export elements. If a media changer device defines one or more media transport elements, these can be used as temporary holding places for data media. If a media changer device does not define a media transport element, data media are transferred directly between storage elements and data transfer elements.

Storage element; a location or ``slot'' in a carousel, tape holder, or magazine which can contain a data medium. It is not a data medium (such as a tape or a CD). Medium changer devices typically contain four or more storage elements.

N is a number from 0 to 255 representing different elements of a given type within a media changer device. If no entries are shown for an element type, the media changer does not contain such an element.

Disable the front panel controls of the media changer.

move source destination
Move data medium from a source element to a destination element.

pos stN
Position medium transport element ``mt0'' in front of ``stN''. This places the media transport ready to retrieve a data medium from the specified storage element. It does not transfer any data medium to the media transport.

Perform a hardware reset on the media changer.

Enable the front panel controls of the media changer.


Each data transfer element is configured and operated as a separate SCSI peripheral device. Storage, data transfer, and import/export elements are configured and operated as part of the media changer device.

For example, a juke box containing one SCSI CD-ROM drive (the data transfer element) is configured as two entities:

Data transfer elements usually have the same SCSI host adapter name, bus number, and ID as the other elements in the juke box, but their LUNs (logical unit numbers) differ. For example, the LUNs of the data transfer element and the media changer device may be 0 and 1 respectively.

Refer to the documentation supplied with the juke box for details of the SCSI configuration of its elements.


media changer control device

juke executable

Sjk include file

See also

backup(ADM), cpio(C), dd(C), jukebox(HW), mkdev(ADM), restore(ADM), tape(HW), tar(C), xbackup(ADM), xrestore(ADM)

Standards conformance

juke is not part of any currently supported standard; it is an extension of AT&T System V provided by The Santa Cruz Operation, Inc.
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003