Whew. This seems to have gone in a direction I really didn't intend; I guess my communication skills are worse than I'd feared. I'm truly sorry I larded my original posting that started this all with so much jargon that folks from other backgrounds found it impenetrable. That is purely inappropriate on a list like this. I didn't take any offense at the question asking about the jargon, and found the exercise of trying to write out a detailed description of all the terms I used quite fun in its own right; it's always satisfying reviewing the basics of a domain you work in. I hope others found the explanations illuminating. I really didn't think my (apparently erroneous) attempt to deduce the background of the questioner from the questions was insulting. Wrong, perhaps, but I don't recall having been mean in that one. If anyone felt I was, I'm truly sorry. -Bennett