As previously noted, a file system is a collection of data resources. A file system may or may not be hierarchical. Levels in the hierarchy, if present, are called directories. Resources with data are called files. Concrete examples of file systems are HDFS or Amazon S3. More abstractly, a web server or FTP server can also be considered a file system.

File systems are never referenced directly within DataFlow but rather are referenced indirectly through paths.

A number of file systems are supported by default in DataFlow. See Supported File Systems for a list.