An ES3 link contains a source ('from') and destination ('to') and has a single direction. Links must be organized in a Directed Acyclic Graph, such that a link does point backward in the graph, thereby creating a loop. The source and destination of a link are ES3 object which are identified by a UUID. This is the destination of a link object. The 'to' object can contain an ES3 'file' or 'transformation' object. This is the source of a link object. The 'from' object can contain an ES3 'file' or 'transformation' object. An unlinked object in one that is not referenced by any link, but is contained in a workflow. An ES3 'file' object represents a file that has been read or written by a data transformation. File 'domains' are well known domains such as 'URL' or 'local file system'. ES3 will accept any domain name that the client/user wishes to use. The domain name, such as "URL" A URL that provides information about the domain. The identifier for this file object that identifies it within the domain. An ES3 data transformation object. Transformations are grouped inside ES3 in collections which are designated by a directory-like name, i.e. '/painter/modscag/sierra' The workflow that this transformation belongs to. An ES3 data transformation may contain a workflow, thus creating a nested structure. The name of the data transformation. The ES3 probulator usually assigns the filename portion of a file path as the transformation's name. The type of the transformation, which might be specified as a URL. The 'userMetadat' section can contain any XML subdocument and is information provided by the client/user. These are command line arguments to the data transformation, i.e. arguments to a Unix shell script or executable program.