The last file to be loaded by the bootstrap process contains
module-level code which will trigger the self-initialization of the
interactive system--including CM. One job of CM is to manage sharing
of link-time state (i.e., dynamic state created by module-level code
at link time). Link-time state of a module used by the interactive
system should be shared with any program using the same module. The
file 
.boot. arch- os/PIDMAP contains information
that enables CM to relate existing link-time state to particular
library modules and also to identify any link-time state that will
never be shared and which can therefore be dropped. It is CMB's
responsibility to construct the PIDMAP file.