Sun Microsystems StorageTek StreamLine SL8500, System Assurance Manual

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Introduction
22 SL8500: Systems Assurance Guide • July 2011 E24254-01
Pass-thru Ports
Figure 11. Pass-thru Port Mechanism
Connecting libraries together with pass-thru ports creates an SL8500 Library
Complex.
Figure 11 is an example of a pass-thru port (PTP) mechanism—an

electro-mechanical device that allows one library storage module (LSM) to
pass a cartridge to another LSM in the same complex.
For example: If an operating system issues a mount request, and all of the
tape drives are busy in that library, the PTP can pass the cartridge to
another library where an idle tape drive can satisfy the mount request.
Important:

The need to plan ahead for the addition of pass-thru ports is extremely
important. The library complex can “grow” in either direction—left or right.
The preferred method of installing PTPs to an existing library is to add the
new library to the left when viewed from the front.
However, the library complex can grow in the other direction—to the
right—but this requires a disruption to the system to renumber the LSMs
and reconfigure the management software.
The following are highlights about the PTP feature:
• All SL8500 libraries come equipped and ready for the addition of the PTP
frame and feature—no additional walls are needed.
• Power for the PTPs comes from the same +48 VDC power bus as the
robotic rails. Both the N+1 and 2N power configurations currently support
the PTP hardware—no additional power supplies are needed.

The SL8500 pass-thru port feature
consists of a separate frame that is
installed between the Drive and
Electronics Module / Robotics Interface
Module of one library with the same
modules of an adjacent library.
Each PTP frame has four separate
mechanisms that can pass up to two
cartridges—per LSM or rail—between
the libraries.
There are eight PTP locations in an
SL8500 library, two per rail (or LSM).
These locations are on the curved
portions of the Robotics Interface
Module near the tape drives.