The morphing of the array doesn't affect the indexing, so that isn't a problem. (It's Memoize BTW, no 'r').

As for the 'interupts problem'. There are many ways of interprocess communication available under Win32, they are just different to *nix. Perls attempts to layer signals on top of windows has never been very sucessful. That said, from what I read, the whole idea of using signals in perl, even under *nix has never really been made to work very well.