mmap

   The Unix system call which establishes a mapping between a
   range of addresses in a user process's address space and a
   portion of some "memory object" (typically a file, one of the
   special "devices" /dev/mem or /dev/kmem or some
   memory-mapped peripheral).  This allows the process to
   access a file at random byte offsets without using the seek
   system call or to access physical addresses or kernel's
   virtual address space.  It can also be used as an
   alternative to writing a device driver since it is usually
   simpler to code and faster to use.

   (1995-02-14)