Personally if the implementation is simple given the task, and the idea is obvious, or combines two existing concepts in an obvious way... it shouldn't be patentable... Anything that is a virtual representation of something real, in terms of software is an obvious idea, and shouldn't be patentable. In fact, for the most part, I can't really think of anything in terms of software, that doesn't have corresponding unique hardware for the past 20 years that is worthy of a patent.