When both servers are fired up, RFC's are exchanged and data transfer starts. Some hosts will have a problem with the current FTP because their file system needs additional host-specific parameters in certain cases. As an example, the IBM operating systems tend to give the programmer a number of options on the logical and physical mapping of a file onto the disk. Indeed, the mode should be chosen on grounds of efficiency, not end use. There weren't enough logically distinct combinations of FTP parameters.
Some common cases require non-invertible transformations on the data.
80 bytes each, i.e., literal card images. That would be downright unfriendly. Thus, the CCN server FTP would have to choose between being useful or being friendly. However, the user who uses only these defaults will probably find he has to later run a utility under TSO to reformat the data. We will provide some mnmonic keywords associated with STOR commands to choose the proper disk mapping.