Come June and the Eclipse Foundation will orchestrate the release of ten of its most prominent projects in an effort to avoid some of the chaos that can accompany  open source team efforts.

This 10-way coordination, code-named Callisto, has been in the works since August 2005. The Callisto release includes updates to BIRT (Business Intelligence and Reporting Tools project), WTP (Web Tools Platform project), TPTP (Test and Performance Tools Platform project) and others. Also included as part of the Callisto plan is the release of Eclipse 3.2, this year’s update of the overarching Eclipse Project.

“What if you want to use the Web Tools and the Data Tools together?” asked Bjorn Freeman-Benson, technical director of open-source process and infrastructure for the Eclipse Foundation. “Last year, we released the two projects on different days. They were close, but they were still two different days. You couldn’t be sure which version of Web Tools to use with which version of Data Tools. People were confused.”

An Eclipse.org release states: “While Callisto is about the simultaneous release of ten projects, it is not a unification of the projects—each project remains a separate open source project operating with its own project leadership, its own committers, and its own project plan.”

Callisto attempts to ensure that numbered releases of 10 major projects work together without coming into conflict. (For example, a plug-in associated with one project shouldn’t override a plug-in that comes with another project.) Callisto does not ensure that each project makes optimal use of another project’s features. If anything, this project synergy will be a byproduct of Callisto rather than an explicit Callisto goal.

As for structure, each of the 10 projects will follow a loosely coupled version-numbering system. For example, the Eclipse Project released in June will be version 3.2, while the Web Tools Platform will be version 1.5, and the Test and Performance Tools Platform will be version 4.2. Each project’s number will continue from where it left off. But each project will be required to use Eclipse’s four-part numbering scheme. Roughly speaking, the four parts of an Eclipse version number represent incompatible_revision, compatible_revision, minor_fixes, and new_build. Most important, each project will contribute its own version number to the Callisto pot. Web Tools release 1.5 will be compatible with TPTP release 4.2 because both releases belong to the Callisto effort.

The Callisto Release Candidate 3 is now available for download. To access the Callisto RC3 projects, the latest Eclipse Platform Runtime Binary (RC4) must be downloaded and the update manager must be used to load Callisto projects.
You can download the Callisto RC 3 from the Eclipse Foundation web site.