THE CATALOG:A FLEXIBLE DATA STRUCTURE FOR MAGNETIC TAPE

摘要

An outline of a generalized storage scheme for large files of highly struc¬tured data (or catalogs) and a descrip¬tion of their realization on magnetic tape. Each datum, large or small, is assigned to one of a number of data classes of which a user may define any number. The over-all organization of a catalog is given by a map that imposes a tree structure on the set of data1 classes. Catalogs may participate as individual data in other catalogs so that the structure of a file may be recursive. A flexible addressing scheme not only facilitates the retrieval of data and sets of data in response to easily formulated requests but also provides a basis for updating catalogs. General procedures called transformations can be used to derive catalogs with new structures from existing catalogs.