=========
Glossary
=========

.. glossary::

   available

      1. TMC identifies and acts based on subsystem responsiveness.

      2. To determine if a subsystem is responsive, TMC reads the state of subsystem devices from their respective Leaf Nodes.

         a. TMC calls the **state()** method on the Tango device proxy to check the device's current state.

            i. This is a network operation.

            ii. The operation will fail if the device is unreachable.

      3. TMC uses this mechanism to collect responsiveness information of an SDP Subarray.

         a. The result is stored in the **isSubsystemAvailable** attribute of the TMC SDP Leaf node.

            i. **True** if the subsystem is reachable.

            ii. **False** if the subsystem is not reachable.

   TRL
      It stands for Tango Resource Locator. Check `ADR-9 <https://confluence.skatelescope.org/display/SWSI/ADR-9+Update+naming+conventions+for+TANGO+Devices+and+Servers>`_ for more details.