A file system for managing data files for access by a plurality of users of a data processing system that includes internal storage (41) for buffering, external storage (44), and a file user interface (I) by which the plurality of users request access to data files. A first level, coupled to the file user interface (41) for temporary storage of data to be accessed by the plurality of users, and generates requests for transactions with external storage (44) in support of such allocations. A second level is coupled to the first level and the external storage (44) and responds to the request for transactions with the external storage (44) for managing the transactions for storage of data to, and retrieval of data from, the external storage (44).