Vensim is organized around models, and data or simulation results that relate to those models. These two concepts are often labeled structure and behavior, and Vensim maintains a strong distinction between the two. If you have worked with spreadsheets you may be used to thinking of a spreadsheet as containing both formulas and relationships and the numbers these generate. In Vensim the formulas and relationship make up the model. The numbers these generate are treated as experiments with the model and they are stored as datasets separate from the model. This allows you to make any number of experiments and retain the results without having to set up additional places to put them.
Vensim uses a workbench toolbox metaphor to deal with models and data. The program is analogous to a workbench that allows you to build and analyze a model and its related data. We will often refer to the main Vensim window as the Workbench, and this is what appears when you start Vensim. The Workbench contains a menu, a model, a variable, datasets, a toolbar, one or more toolsets, controls, tool output windows and model building windows.
The model (world.mdl) and variable (deaths crowding multiplier) are named in the title bar of the window. The datasets in use (current and base) are named in the Control Panel. The menu is below the title bar and the Main Toolbar below the menu. The Analysis Toolset is visible on the left. The Build window contains the model in the Workbench (this is normally the case unless there are multiple Build windows open). The Control Panel is open showing the Datasets tab. There is tool output from the Tree Diagram and the Strip Graph tools. The Status Bar reflects the Build window because the Build window (containing the model) is the active window (The Windows>Keep Build Behind toggle was checked for the above screenshot).