Robert A Rader

US Patent:

52533425, Oct 12, 1993

Filed:

Jun 18, 1992

Appl. No.:

7/900545

Inventors:

Marion L. Blount - Mahopac NY
Stephen P. Morgan - Hartsdale NY
Katalin A. V. Rader - Austin TX
Robert K. Rader - Austin TX

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1300

US Classification:

395200

Abstract:

A communication protocol for direct communications between operating system kernels of a plurality of processors in a clustered-type, shared virtual memory, multi-processor data processing system is disclosed. Each processor unit includes a intermachine communications software system ("IMCS") which may-be used by a trusted kernel of the operating system of the processor to communicate with a service in another processor, either directly or through an intermediate processor. Communications are initiated when a user prepares a message in accordance with pre-programmed instructions from the IMCS in a standard format. Once the message is prepared, the user calls IMCS which selects a route for the transmission of the message over a serial communications link to the receiving processor using a "request to send immediate" serial link level protocol. The message is initially directed to a common buffer pool. IMCS calls special software to read the header of the message to determine the identity of the destined server and to determine if the buffer in the buffer pool assigned to the called service has available buffer space to accept the message.

US Patent:

52222179, Jun 22, 1993

Filed:

Jan 18, 1989

Appl. No.:

7/298384

Inventors:

Marion L. Blount - Mahopac NY
Stephen P. Morgan - Hartsdale NY
Katalin A. V. Rader - Austin TX
Robert K. Rader - Austin TX

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1300

US Classification:

395325

Abstract:

A system for maintaining the reliability of shared data structures, such as message queues, in a multi-processor data processing system is disclosed. The system includes a plurality of virtual memory-type processor units in which the processors share virtual memory and can access each one of a plurality of virtual memory segments by the same virtual memory address. The system assures the reliability of system-wide shared data structures in the event of a failure of one of the processors by maintaining at least two copies of each data structure and by maintaining two copies of a table used in locating such data structures. The system updates copies of such shared data structures that are stored in at least two different processing units with the results of a specified data processing transaction, which may have affected the information in such data structures, in a manner to insure that either identical updates occur or no update occurs. The system further insures that any changes that might have occurred in the information stored in the data structure prior to the end of an aborted transaction is returned to the initial state to permit the transaction to be retried.