The criteria which inspired the design of DIRA2 were prompted by the simplicity of use and maintenance of the structure itself. We choose to maintain the data in their original format to save data legibility (to make comparison with original printout) and to allow data update by simple tools like editors or user written programs.
In this chapter we describe the structure of the data files and the structure of the system files. This information must be known by the users that need to work with a Personal Data Base and that want to insert new catalogues. The management of the system files of the Personal Data Base is made by PDB_MANAG, while the DB_INFO and PDB_INFO commands show the system files items of the public and private data base.