Evolution of SCA, WAS, and WPS

Here are some insights from Overview of SOA Feature Pack for WAS 6.1, which discusses the IBM WebSphere Application Server V6.1 Feature Pack for SOA, one of the WebSphere Software Early Programs:

The stuff in the feature pack adds SCA and SDO to WAS. (WAS already has an older version of SDO in it; this updates it.) This SCA (and SDO) code isn't pulled out of WPS; rather, it's based on Apache Tuscany (to which IBM is one of the main committers). Tuscany also isn't based on WPS exactly; it's based on the specs being produced by the OSOA, which are based on earlier versions of the specs developed by IBM while developing WPS. Tuscany is open-source, so its impls of SCA/SDO are available to other vendors as well.

IBM is taking Tuscany, adding in proprietary extensions, wrapping that up as the feature pack, and adding it to WAS 6.1. Then the plan is for WPS 6.1 to be built on WAS 6.1 with this feature pack, but still be backwards compatible with WPS 6.0.x and its earlier, more proprietary implementations of SCA and SDO. So it looks like WPS 6.1, by being built on WAS 6.1 with this feature pack, will be built on Tuscany, which implements the OSOA specs. (Of course, nothing is definite until it's done.)