A small footprint device can securely run multiple programs from unrelated vendors
by the inclusion of a context barrier isolating the execution of the programs.
The context barrier performs security checks to see that principal and object are
within the same namespace or memory space or to see that a requested action is
authorized for an object to be operated upon. Each program or set of programs runs
in a separate context. Access from one program to another program across the context
barrier can be achieved under controlled circumstances by using a global data structure.
