Controlling Software Modes; Connected Mode; Disconnected Mode - StorageTek 4410 Hardware Operator's Manual

Controlling Software Modes

The terms "connected mode" and "disconnected mode" refer to the relationship
between the controlling software and an ACS. An ACS may be connected to one host
while it is disconnected from another. A single host may be attached to several ACSs,
some of which are connected to the controlling software, and some of which are
disconnected from it.
If your system supports a dual LMU configuration, the ACS can be in a condition
referred to as "standby mode." Two LMUs exist in a dual LMU configuration: one master
LMU and one standby LMU. If the master LMU stops functioning, the standby LMU
becomes the master and takes over the functions.

Connected Mode

Controlling software is connected to an ACS when both of these conditions are true:
• The controlling software is executing on that particular host.
• The host and the ACS are communicating with a minimum of one station online to
the ACS (a station is the connection between the host and the LMU).
While the controlling software is connected to the ACS, messages from the host are
routed to the ACS, which automates cartridge mounts and dismounts.

Disconnected Mode

Controlling software is disconnected from an ACS when both of these conditions are
true:
• The controlling software is executing on that particular host.
• The host and the ACS are not communicating (no stations are online to the ACS
from that particular host).
In disconnected mode, no automated tape activity can occur for this host using this ACS.
In a multiple-host environment, however, because the ACS is still capable of automated
operations, you can semi-automate mounts and dismounts by issuing software
commands from the console of a connected host. As the mount and dismount messages
appear on the console of the disconnected host, you can issue software mount and
dismount commands from the console of a connected host to direct the LSM robots to
perform the mounts and dismounts.
9206 Eleventh Edition
Controlling Software Modes
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