OK, to say that the Distributed Computing Environment (DCE) is dead is probablyoverstating it, as parts of DCE will survive into the foreseeable future. Iona, a majorORB vendor, has recently licensed Encina from Transarc (DCE transaction services) andTivoli which was an outgrowth of the virtually forgotten DME (Distributed ManagementEnvironment) are best of breed products (and interestingly IBM organizations). However,Iona's embracing of Transarc's Encina has a singular weakness in that Encina still onlysupports the XA interface. Additionally, Encina (Orbix OTM) does not have the utilitiesthat are available in the DCE environment. Alternatively, Integrated Transaction Service(ITS) from Inprise, (formerly Borland, formerly Visigenics) supports both native and XAinterfaces.

Although, in all fairness to Transarc, the TRAN module used for Encina is much moremature. In the X/Open scheme, XA-compliant databases are called Resource Managers. The XAspecification defines the interaction between the RM and Transaction Manager (TM), whichmanages distributed transactions. In Encina, XA is implemented in the TMXA module. TMXA,in turn, registers callbacks with TRAN to determine when transactions are prepared,aborted and committed.

The open database XA environment part of the DCE transaction services framework, whichneither Oracle nor Sybase has implemented properly with respect to performanceengineering, should probably be abandoned. The DBMS vendors, other than IBM DB2 fornon-MVS environments, never took XA seriously. Maybe IBM remains the lone driving forcebehind XA. DBMS vendors and other data technology firms usually prescribe Sybase'sReplication Server for cross DBMS or cross server transactional implementationsrequirements.

-- F.T.

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