I googled quite a lot but beside installation instructions I could not find an answer to my simple question:
What is a Virtuoso Application distribution (VAD) package and what it is useful for?
I am mostly interested in dbpedia: having already loaded dbpedia data, what is the added value of installing dbpedia_dav.vad ?
Many thanks.
Product documentation is a useful resource to start with --
6.1.4. VAD - Virtuoso Application Distribution
VAD provides a package distribution framework for installation, management, dependency checking, and un-installation of Virtuoso applications. A VAD package contains all required Virtuoso components, which would constitute an application or hosted solution, within a single distributable file. A VAD package cannot contain any system parts independent of Virtuoso, thus excludes operating system executables, shared objects, installers, and settings.
To your specific --
The DBpedia VAD includes various things, like the "green page" template, which are not part of the DBpedia data set nor the base Virtuoso install.
For the future --
DBpedia-specific questions are often better raised to the DBpedia Discussion list.
Virtuoso-specific questions are often better raised in Virtuoso-specific arenas, such as the Virtuoso Users mailing list, the public OpenLink Support Forums, or a confidential OpenLink Support Case.
ObDisclaimer: I work for OpenLink Software, producer of Virtuoso, supporter of DBpedia.