Common-Description:
 This is a library for handling page faults in user mode.  A page fault occurs
 when a program tries to access to a region of memory that is currently not
 available.  Catching and handling a page fault is a useful technique for
 implementing:
 .
   - pageable virtual memory,
   - memory-mapped access to persistent databases,
   - generational garbage collectors,
   - stack overflow handlers,
   - distributed shared memory,
   - ...