LOD2 Stack Repository
In order to guarantee stability of the available component stack, a multi stage environment has been setup. There exist 3 stages currently:
• The developers' area: here the developers put their packages.
• The testing stage: this is a collection of LOD2 packages that are subject to integration tests. The goal is to detect with automatic testing problems in the installation of the packages.
• The stable stage: this is a collection of LOD2 packages that pass the tests.
The LOD2 stack managers are responsible for moving packages from the developers' area into the testing stage and then to the stable stage.
Orthogonally we have created 2 repositories that are OS-release dependent. These contain components that are dependent on the OS. The typical example is Virtuoso for which Ubuntu 12.04 64 bit builds are provided. Build and installation instructions are present to support more recent and other Linux distributions.
Developers have to contribute a Debian package with the correct LOD2 stack conﬁguration. The rationale behind this choice for this approach is to distribute the knowledge on building packages to all partners, but more important to create awareness for software deployment. When the component owners are responsible for building the Debian packages they face the imperfections that make their software hard to deploy. That experience has as positive eﬀect that deployment issues are tackled early on. All necessary information for the developers is collected in the contribution documentation.
The LOD2 stack repository distributes software components. However in addition to these components, there are more components or information sources valuable to the LOD2 stack available online. These come in two categories:
• software components which are only accessible online due to various reasons: special setup, license rules, etc. Examples are the Sindice search engine and PoolParty.
• information sources: for example dbpedia.org and vocabulary.wolterskluwer.de.
Installing the LOD2 Linked Data Stack
1. Setup a Ubuntu 12.04 64 bit LTS system.
2. Download the repository package (of the stage of interest) and install it.
3. Update the local package cache.
4. Install the whole LOD2 stack or selected components.