The TUXEDO System: An Open On-line Transaction Processing Environment

This paper briefly summarizes some recent IBM work in the areas of distributed commit protocols, andrecoverable messaging and queuing. We discuss the original presumed nothing commit protocol of SNALU 6.2 and the current industry standard presumed abort (PA) protocol which we originally developedin IBM’s R* project. We also discuss generalized presumed abort (GPA) which resulted from the inte-gration of PA into LU 6.2. GPA has been implemented in DB2 V3. We provide a brief introduction tothe Message Queue Interface (MQI), an architected application programming interface, and MessageQueue Manager (MQM) MVS/ESA, one of the IBM MQSeries products that implements MQI. Some in-ternal design features of MQM are also described.