Friday, December 21, 2007

Fedora 3.0b1 is released

The first beta version of Fedora 3.0 is now available. I am thrilled about this (even though we're going to wait until after the release of final 3.0 to upgrade) because this includes a change that I have wanted for a long time -- the Content Model Architecture (CMA). When the Fedora architecture was first designed, the tight bindings between objects and their disseminators seemed to be a good thing. As repository services were developed using Fedora, though, some of us discovered that we needed to make changes to disseminator mechanisms after we developed them. In the previous (current) architecture, because the objects were tightly bound to the disseminators we could not make changes to the disseminators unless NO objects were bound to them. In other words, we had to purge disseminators that were bound to objects (the easiest way was to actually purge the objects), then update the disseminators, and then re-ingest the objects and re-establish bindings. CMA adds the ability to formally instantiate content models in relation to objects, also making it easier to update disseminators without the purging of objects. This also supports a new ability to validate objects against content models, a very desirable QA feature.

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