The Expansion Unit - Compaq SW TL881 DLT Mini-Lib/1 Manual

1-2 Compaq TL881 Minilibrary System Users Guide
In a MiniLibrary system, you can combine modules to provide the right
combination of capacity and performance to meet your present storage
requirements. Compaq's MiniLibrary storage architecture lets you add
modules to optimize throughput and capacity as your needs change.
MiniLibrary Storage Architecture
When connected as a system, the robotics in the Expansion Unit act as
commanded by the host computer(s). The host(s) need no knowledge of the
internal geometry of the system, or of the actions or capabilities of the
MiniLibrary Base Modules or Data Units.
The Expansion Unit presents to the host(s) a single SCSI medium changer
device with a single SCSI Medium Transport element, several SCSI Storage
elements equal to the total number of cartridge magazine slots, a number of
SCSI Import/Export elements as specified by the user during configuration of
the Expansion Unit, and a number of SCSI Data Transfer elements equal to the
total number of drives in the system.
Flexibility
Compaq's MiniLibrary storage architecture is uniquely suited to growing
storage needs. Its flexible library robotics system enables you to start with a
system configured to your present requirements, confident that as your storage
needs evolve, you can easily modify the MiniLibrary by adding modules and
extending the Pass-Thru Mechanism. Add drives for faster performance or
magazine space for greater capacity, as needed. Then just turn on the power,
and immediately the system updates the system map so the host is informed of
the expanded capability.

The Expansion Unit

The Expansion Unit (Figure 1–1) integrates the robotics in the individual
modules into a single, coordinated library robotics system. The Expansion
Unit performs and maintains an inventory of all media present in the system,
including bar code data. All necessary system control operations may be
performed from the control panel of the Expansion Unit, as well as from the
host via software. The SCSI interface for the library robotics is designed for
high-speed communication with the host, and Fast/Wide SCSI configurations.