Abstract: Hybrid lock and unlock capabilities are provided for a threaded computing environment. For example, kernel locking services are selectively employed in conjunction with functions in the POSIX threads standard to provide a lock capability and an unlock capability. The hybrid approach determines which lock scheme to employ by evaluating whether one thread or multiple threads concurrently desire a resource lock. When only one thread desires the lock, the thread is directly assigned resource ownership employing one of an operating system primitive lock process or a hardware lock process. An alternate lock process is used to obtain resource ownership when multiple threads concurrently desire the lock. This alternate process employs at least one function in the POSIX threads standard to implement a queue of waiting threads. A similar hybrid approach to the unlock capability is also provided.
Type:
Grant
Filed:
August 25, 1998
Date of Patent:
August 15, 2000
Assignee:
International Business Machines Corporation
Inventors:
Rama K. Govindaraju, Elizabeth Anne Kon, Robert Michael Straub, William G. Tuel, Jr.
Abstract: A quiesced and synchronous distributed data processing system includes a primary node, a secondary node and a switch between the primary and secondary nodes. The TOD for the primary node is set depending on the system. The invention sets the TOD for the switch based on the TOD of the primary node. The primary node then verifies the switch TOD. If verified, the TOD for the secondary node is set, based on the TOD of the primary node. Finally, the secondary node self-verifies its TOD.
Type:
Grant
Filed:
April 8, 1997
Date of Patent:
July 20, 1999
Assignee:
International Business Machines Corporation
Inventors:
Robert Francis Bartfai, Derrick LeRoy Garmire, Jay Robert Herring, Francis Alfred Kampf, Nicholas Paul Rash, Kevin John Reilly, Craig Brian Stunkel