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+The Collaborative International Dictionary of English v.0.48
+defines a mechanism as:
+
+> The series of causal relations that operate to produce an
+> effect in any system; as, the mechanism of a chemical
+> reaction.
+
+This is, a mechanism is a function that produces some result.
+As mechanisms determine the type of result, they necessarily
+impose some [[policy]] (rules). Mechanisms that are referred
+to as policy-free are those that minimally impose policy.
+
+A process can be used to encapsulate a program instance. On Unix,
+a process is associated with a UID. This UID, in part, determines
+what the process is authorized to do. On a [[microkernel]],
+the policy that controls what resources a process may access
+are realized separately. This may achieved through the use of
+UIDs, however need not. Thus, the processes mechanism on such
+microkernels impose less policy than on Unix. A process is not
+policy free as it is possible to use other mechanisms to
+encapsulate a program instance, e.g., [[SFI]] and tainting
+ala [[Asbestos]].