Many applications of visualization tools call for a direct interface to external data sources, especially ones that generate data to be studied (e.g. a computational simulation). The execution model of Data Explorer provides the framework for real-time visualization of data generated asynchronously by such a process. An external data source is linked into a Data Explorer network by incorporating a communications module, which receives data from the external source, often across a socket, and passes the resulting data object to the module's output. This module (and its descendents) will only run when the external data source has indicated that new data are available (see 11.2 , "Asynchronous Modules" in IBM Visualization Data Explorer Programmer's Reference).
Data Explorer also provides a mechanism for direct manipulation of the executive (e.g., mode, passing data, error handling, etc.) and the user interface (e.g., window visibility and mode) from an external application. This allows control of Data Explorer from other software and peer-to-peer communications (see Chapter 17. "DXLink Developer's Toolkit" in IBM Visualization Data Explorer Programmer's Reference).