Program Transferability - Data Access Representation for Secondary Storage
Stuart C. Schaffner, David B. Loveman, Robert E. Millstein · 1972
This report presents theoretical work which should lead fairly directly to analytical tools which can materially reduce the coat of transferring programs from one computer system to another. A unified, general description of data files and data access methods, called the data access representation, is developed which, it is asserted, is detailed enough to allow efficient use of complex I/O devices, yet simple enough to make possible the development of analytical tools to study and modify programs using the data access representation. As an example of such a tool, an algorithm is developed which will alter a program to compensate for any of a class of data file structure transformations similar to those required to transfer a data file from one I/O device to another. The data management routines of three important operating systems are then considered: IBM OS/360, CDC SCOPE, and HONEYWELL GECOS. Each is described in detail in terms of the data access representation.