DATA PROCESSING

Data streams are stored in a non-structured arrangement in which related data is defined by a reference in a first data stream identifying a data element in a second data stream. Instructions are received from a user to establish a virtual file system that provides a structure for a plurality of application files, wherein the information in each of the application files is contained in a plurality of data streams. The structure is defined by at least one hierarchical index, the nodes of said index being data streams. Instructions are received to write data to or read data from the virtual file system, and relevant data streams are modified to reflect instructed manipulations to data presented to a user via the virtual file system.