Better yet... um... Won't the multiple processes use the same cache content if it is on disk? Maybe I should ditch the shared memory option and just put a 8GB cache dir in my /dev/shm dir... I mean it is a file system. Perms are same as on /tmp... owner writeable.... ...If I can just get it to do "write-back" to disk in bckground, so it can recover after a reboot... Might simplify your algorithms quite a bit... you certainly won't have the contention issues that you would fetching things off disk...