One of the important features of ZEBRA is its ability to handle the transfer of data structures to and from an external medium. This is performed by calls to routines in the FZ part of the system, and the user does not need to program any explicit Fortran input/output statements. But the power of the system goes beyond that of a simple data transfer. It is able to maintain the integrity of a data structure between an output operation and a subsequent input operation by appropriate changes to the values of the links connecting the structure. In addition, ZEBRA permits input/output to either sequential or direct access files, depending on the nature of the data and, very important, it also provides two modes of data representation. The first is called native mode, and implies that the data undergo no conversion when transfered between storage and the external medium. Such data may be read only on a computer of a compatible architecture. The exchange mode, on the other hand, allows transfer of data between a large variety of computers by making appropriate conversions to and from an interchange format.
On the other hand the ZEBRA RZ package permits the storage and retrieval of ZEBRA data structures or Fortran vectors in random access files. Files may reside on standard direct access devices such as magnetic disk, or be mapped to virtual memory. RZ file s can be accessed by several users simultaneously, even across networks. Remote file access and transfer is provided for RZ files using standard tools, such as NFS and ftp. In the heterogeneous environment, the tools provided in the CSPACK [2] package may be used.
The RZ package is not a relational database management system, but organises data in a hierarchical manner which is suitable for many applications in High Energy Physics, and probably outside.