Sorry for going off-topic here to the thread, but ...
As someone studying the language, can you explain what the と portion of the name means? I am aware of the ある (有る) portion, "to exist", and that と is being used here to represent a clause, eg "Xと言った" (X said), "Xと思った" (X thought).
But in this case, there's nothing before とある, so why say と at all in this case? Why not just say あるOS?