Watch OSGi: The Foundation (58 min)
The presentor is Peter Kriens, OSGi Technical Director who was also recently interviewed by InfoQ, where among his responses he gave a brief synopsis of the why and how of OSGi:
My long story before about the way that OSGi got started: when you look at the problem of being able to work with code from different parties, and be able to let them collaborate in the system, that's actually the problem we are facing today in most of the enterprise software as well. How do you get the components from all these different departments and from all these different open source groups, how do we get them in the VM running together in a secure and reliable way? And if you want to do that you need a modular standard, you need something that clearly delineates the parts that you are building. And OSGi has been doing it because of that earlier home automation problem, and that's exactly the problem that you see in the market as well today. On top of that, you need to be able to update the software on the fly because restarting big servers is taking more and more time. Being able to update parts of the code on the fly saves time there as well.InfoQ has been covering OSGi quite heavily, see http://infoq.com/osgi.
Plus the dynamics is something that people really like, the fact that you can have several demonstrations now that people make web based applications and they can plug in a new bundle and that has extra features to the web pages of the applications. Having this modularity that you can extend your applications and that you don't have to have everything running at once, which were key requirements in 1998 for home automation, they have become common. That's what people want: it needs to be reacting immediately; the dynamicity, and you need to be able to have modularity to let different teams work together and make it work in the end on the system.