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diff --git a/mechanism.mdwn b/mechanism.mdwn new file mode 100644 index 00000000..ec694960 --- /dev/null +++ b/mechanism.mdwn @@ -0,0 +1,22 @@ +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]]. |