IPC::ShareLite provides a simple interface to shared memory, allowing
  data to be efficiently communicated between processes.  Your operating
  system must support SysV IPC (shared memory and semaphores) in order to
  use this module.   

##</code><code>##

The Mmap module lets you use mmap to map in a file as a perl variable
rather than reading the file into dynamically allocated memory. It
depends on your operating system supporting UNIX or POSIX.1b mmap, of
course.

##</code><code>##

-- 
Joost       downtime n. The period during which a system
            is error-free and immune from user input.