Back on topic please.
Basically an image consists of two parts:
1- Linux, as it is the operating
2- Einigma2 as the DVB-application
Additionally some plugins may be pre-installed.
Ad1: The OpenEmbedded organisation creates Linux for embedded systems. As an STB has only limited sources available, and only limited tasks to fulfil (after all it is not a multi purpose PC) a dedicated Linux distribution is being used. ViX shares their OE with other teams. For all the details about our OE see
Code:
https://github.com/oe-alliance
For all details about the OE-organisation see
Code:
http://www.openembedded.org/wiki/Main_Page
It may be clear that Linux consists of a huge number of packages. We do our best to keep it up-to-date, which is required for several reasons (a.o for safety, remember the recent HartBleed bug). Just the very same reason why MS keeps Windows up-to-date.
Ad 2: Enigma2 is the main (in fact the only) application running on your STB. So all you see, all you interact with is E2. It takes care of everything related to watching and recording. It also provides the Graphical User Interface you use to interact with the box.
Compare it wit a PC on which you have just one program running full screen: that gives you the idea that you only deal with that program, and leaves you with the idea that only that program is alive. But on the background you always need the operating system, without which you can't run a PC at all.
I hope this clarifies things a bit.