Ross A Mauri

48335940, May 23, 1989

Dec 22, 1986

6/945148

Harry G. Familetti - Fishkill NY
Charles W. Lickel - Poughkeepsie NY
Ross A. Mauri - Poughkeepsie NY
Mark E. Swallow - Poughkeepsie NY
Janis L. Coltin - Poughkeepsie NY

International Business Machines - Armonk NY

G06F 900

364200

An in-storage table pair structure is disclosed which extends to the user of the data processing system the internal structures of a component of the operating system. The table pair structure includes pairs of tables that are pointed to by a table pair pointer. A table pair pointer is a double word of virtual storage in which the first word is the address of a user-defined table and the second word is the address of a developer-supplied table. Both tables form a table pair. The table pairs permit functional routines (IETDFs) to reference data in both developer-supplied tables as well as user-defined tables in order to tailor a component of the operating system. The IETDF locates a particular table, or set of tables, by first referencing a global control block which contains addresses of two router control blocks. One is the developer-supplied router control block which contains table pair pointers to all developer-supplied tables that are used by the IETDFs and the other is the user-defined router control block which contains the table pair pointers for all user-defined tables that are used by all IETDFs. The user, through entries in the user-defined table, can add unique table entries that define new functions and override developer-supplied table entries, without actually making changes directly to the operating system or providing exit routines, by utilizing the same table entry identifier as is used to identify the corresponding entry in the developer-supplied table.