Application Entities exchanging information on media use the DICOM File Service as specified in PS 3.10 for access to, or creation of, File-sets. This File Service provides operations that support three basic roles, which are File-set Creator (FSC), File-set Reader (FSR), and File-set Updater (FSU).
These roles are depicted on an Application Data Flow diagram by directional arrows placed between the local Application Entities and the DICOM Storage Media on which the roles are applied.
— File-set Creator (FSC), denoted by [pic];
— File-set Reader (FSR), denoted by[pic] ;
— File-set Updater (FSU), denoted by [pic];
— Physical movement of the medium, denoted by [pic] (with or without arrowhead)
Figure 5.1-5 illustrates the three basic roles.
Figure 5.1-5 FILE-SET ACCESS
The local interactions shown on the left between a local Real-World activity and a local Application Entity are depicted by a dashed line. The arrows on the right represent access by the local Application Entity to a File-set on the DICOM Storage Medium. When an Application Entity supports several roles, this combination is depicted with multiple arrows corresponding to each of the roles. The dotted arrow symbolizes the removable nature of media for an interchange application.
Note: The use of two arrows relative to an FSC and an FSR should be distinguished from the case where a double arrow relative to an FSU is used. For example, an FSU may update a File-set without creating a new File-set, whereas a combined FSC and FSR may be used to create and verify a File-set.