H.G.Muller wrote:By the way, how do I know if the name for a chess engine is already taken?
I would like to reserve the following names for the engines I am working on, but I have no idea if there already exist engines with such names...


Well, checking the various sites like
www.playwitharena.com, wbec-ridderkerk.nl etc., Arnaud's Chess Corner or the WB history would be a good idea. Olivier Deville's ChessWar also seems to include practically every available engine out there.
But simply a google search for "joker chess engine" should suffice.
It would have prevented the BBChess and Eden2 disasters.