Hi, I need some pointers and suggestion in the following problem: I have a very large time-series data. I need to perform some operation on that. At any instant of time, I only need a window-full of data, size of window being known. Starting from the first point, I slide the window towards right and operate on the data that reside in the current window. Currently, I read all of the data to arrays which takes a lot of space and hence GC takes up lot of time. After reading "Streching Storage Manager: Weak pointers, Stable names" paper, I had a feeling that I can do something better for my problem, especially weak pointers seem to be useful. But I do not really get the thread. What I would ideally like to do is: read all the data lazily into some data structure and as I slide the window towards right, I will invalidate the data that fall before the start point of current window. By invalidating, I mean I will somehow tell the GC to reclaim that space if necessary. Is there any way in which I can do this in Haskell, or there is a better(simpler) solution for this. Thanks, Saswat