Workspace
Each file contains exactly one workspace. The workspace provides the 'box' within which all collections (models) are collected. Within a workspace, certain information is shared across all collections:
Global parameters (if defined)
Resources and calendars (if defined)
Global variables (if defined)
Classification schemes and categories (if defined)
Thus, global variables can be defined for use by all collections (models) in a workspace. This can be useful to create multiple simulation models for parts of the same system, which are configured to depend on the same parameters.
All this shared information is shown in the explorer window located at the left-hand side of the main application window, when a model window is open.