Kenneth J Lawrence

US Patent:

54308666, Jul 4, 1995

Filed:

Apr 7, 1994

Appl. No.:

8/224388

Inventors:

Kenneth J. Lawrence - Rochester MN
Michael J. McDermott - Oronoco MN

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1116

US Classification:

395575

Abstract:

A data processing system having a pair of mirrored storage units maintains a state record of the mirrored pair in system memory. In order to be able to determine state when the system is re-initialized, this state information is also stored on each storage unit of the mirrored pair, and in an alternate location. When the state changes, the operating system writes the new state to those storage units which are still functioning, and to the alternate location. In order to prevent ambiguous situations, only certain defined state transitions are permitted. When the system is re-initialized, it attempts to read the state information stored on the storage units. If either unit can not be read, the system substitutes the state retrieved from the alternate state record for the state that would have been read from the non-responding unit. This pair of states from the two units index an unique entry in a state derivation table containing the resultant state.

US Patent:

59208635, Jul 6, 1999

Filed:

May 31, 1997

Appl. No.:

8/866955

Inventors:

Michael Dennis McKeehan - Rochester MN
Teresa Chung Kan - Rochester MN
Kenneth James Lawrence - Rochester MN

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1700

US Classification:

707 10

Abstract:

A system, method, and apparatus for enabling a thin client to participate in a global transaction in a distributed object-oriented transaction processing environment that commits resources according to a two-phased commit protocol. The thin client is configured with a pseudo-transaction manager (PTM), and a remote server managing the commit procedure is configured with an object transaction manager having an interface to the (PTM). When an application on the thin client sends a request to begin a transaction, the PTM creates a temporary propagation context including a Global ID identifying the transaction and sets a flag in the context to indicate that this is a new transaction. The context is sent to a remote server for execution of a remote method. Upon receipt, the remote server recognizes that this is a new transaction and creates a real propagation context including its Resource Coordinator Proxy ID, the global ID, and a Recovery Coordinator Name useful for a recovery process in the event of transaction failure. The real context is replied to the PTM, which updates and replaces its temporary context with the real context.