Logical Unit Number - CXtXdXsX Nomenclature in Unix

CXtXdXsX Nomenclature in Unix

From the computer perspective, SCSI LUN is only a part of the full SCSI address. The full device's address is made from the:

• c-part: controller ID of the host bus adapter,
• t-part: target ID identifying the SCSI target on that bus,
• d-part: disk ID identifying a LUN on that target,
• s-part: slice ID identifying a specific slice on that disk.

In the Unix family of operating systems, these IDs are often combined into a single "name". For example, /dev/dsk/c1t2d3s4 would refer to controller 1, target 2, disk 3, slice 4. Presently Solaris, HP-UX, NCR, and others continue to use "cXtXdXsX" nomenclature, while AIX has abandoned it in favor of more familiar names.