This content has been copied from my previous web site, and hasn't yet been updated since mid-2001; I hope to update it soon.

The proposed specification for Real-Time CORBA 2.0 was approved by OMG's Architecture Board on July 12, 2001; the specification will become official within about six weeks.

Real-Time CORBA 2.0 is intended for dynamically scheduled distributed real-time systems -- it was originally referred to as "Dynamic Real-Time CORBA." Real-Time CORBA 2.0 includes a framework into which application-specific schedulers can be plugged, thus providing a standards-based context for solving a common problem in many real-time computing systems. Real-Time CORBA 1.0 is for the simpler case of statically scheduled, fixed priority, systems.

Real-Time CORBA 2.0 also makes an important additional contribution to building cost-effective standards-based distributed real-time systems. It addresses the common need to spread a real-time application across multiple physically dispersed computing nodes -- a more general concept than the traditional notion of making objects on remote nodes be accessible over a network. It does this by including a distributed real-time programming model based on "distributable threads." Distributable threads are analogous to conventional threads, except that they are not each confined to executing methods in a single object. A distributable thread may span multiple objects on multiple hardware nodes, carrying its timeliness parameters (such as a deadline, etc.) and other parameters (resource ownership, etc.) with it so that it is scheduled appropriately at each node it visits.

The CORBA distributable thread programming model is based on the "distributed (trans-node) thread" abstraction first introduced in the Alpha distributed real-time OS kernel and its subsequent OS and middleware derivatives. See a presentation about Distributed Threads and a paper about An Architectural Overview of the Alpha Real-Time Distributed Kernel from the Proc. of the USENIX Workshop on Microkernel and Other Kernel Architectures, April 1992. The idea of distributable threads was hinted at as "activities" in the Real-Time CORBA 1.0 specification.

The team of vendors that submitted this proposed specification to OMG is comprised of Eternal Systems, ExperSoft, Lockheed Martin, OIS, and TriPacific, with support from MITRE.

(Alpha's distributed threads are also expected to be influential in the Distributed Real-Time Specification for Java, proposed in Sun Java Specification Request JSR-000050.)

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