Sun Microsystems SL8500 manual Pass-thru Ports

Library Complex

Pass-thru Ports

A PTP is an electro-mechanical device that allows one Library Storage Module (LSM) to pass a cartridge to another library storage module within the same complex.

For example: If an operating system issues a mount request, and all the tape drives are busy in that LSM and library, the PTP can pass the cartridge to another library where an idle tape drive can satisfy the mount request.

There are eight PTP locations in an SL8500 library, two locations per rail (or LSM). These locations are on the curved portions of the Robotic Interface Module near the tape drives. Therefore, they provide quick access to the drives.

The SL8500 PTPs consist of a separate frame (FIGURE 1-8) that is installed between the Drive and Electronics Module and the Robotics Interface Module. Each frame has four separate PTP mechanisms that can pass up to two cartridges each between LSMs (one cartridge mechanism) for a total of eight cartridges.

The maximum size of a library complex connected through PTPs is 7 libraries.

FIGURE 1-8Pass-thru Port

Note – Because elevators transfer cartridges from one LSM to another, these transfers are also pass-through operations. The elevators are thus internal PTPs, considered by host software to be on Panel 0.

The following terms and definitions apply to SL8500 PTP operations:

Home library	Provides power, signal, and control lines to the PTP mechanisms. This is the
	library on the right as viewed from the front.
Away library	Always located on the left side of a Home library, as viewed from the front.
Source	Contains the home slot location for the cartridge that will be passed through
	to an adjacent library.
Destination	Contains the tape drive or slot location in the adjacent library where the
	cartridge will be mounted or stored.

20 StreamLine™ SL8500 Modular Library System User's Guide • March 2007 Revision K • 96154