Patent ID: 7185028

Claim:
Data processing unit comprising: a data network; a file server integrated into the data network and having a separate server data memory and comprising at least one primary data file system, data files stored on the server data memory being stored in said primary data file system; a post positioned data storage unit having a secondary data memory comprising a first storage medium and a second storage medium for storage of data files of at least one secondary data file system; the data files of the primary data file system being divided into at least two primary activity groups with a different hierarchical ranking in accordance with a primary activity criterion by means of a primary hierarchical memory management, the primary hierarchical memory management copying at least the data files of the primary activity group with a lowest ranking into said at least one secondary data file system on said secondary data memory and the primary hierarchical memory management generating metadata from the copied data files of the primary activity group with a lowest ranking; and the secondary data file system dividing the data files stored on the secondary data file system by means of a secondary hierarchical memory management into at least two secondary activity groups with a different hierarchical ranking in accordance with a secondary activity criterion.