This International Standard specifies the file structure and the labelling of magnetic tapes for the interchange of information between users of information processing systems. This International Standard also specifies — volume and file structure; — basic characteristics of the blocks containing the records constituting the file; — recorded labels for identifying files, file sections and volumes of magnetic tapes; — four nested levels of interchange. Furthermore, this International Standard specifies requirements for the processes which are provided within information processing systems, to enable information to be interchanged between different systems, utilizing recorded magnetic tape as the medium of interchange. For this purpose it specifies the functions to be provided within systems which are intended to originate or receive magnetic tape volumes which conform to this International Standard.