Wow. You really went to a lot of thought with your response. Thanks for taking the time. You're right about storage; it wouldn't be too much on disk. Thinking in terms of a practical solution, the tied array idea is a really good one. I guess I was just looking for a compromise between that sort of solution (storing data each second, which is in most cases a lot more data proportionally than storing data for each logon and logoff) and not having to run through the whole dataset to find the answer. Fortunately, I think I found what I'm looking for.

Thanks for such a thoughtful answer! =)
--

Love justice; desire mercy.