On the use of feedback control in the design of computing system components

Feedback controllers are typically applied to computing systems by acting on some quantities ("tunable parameters" in the computer science lexicon, e.g., a packet drop rate) to attain some goal (e.g., a required bandwidth allocation). In other words, control loops are closed around the computing system. In the authors' opinion, this is definitely a partial use of control. Many critical parts of computing systems should not be controlled, but rather redesigned in the form of controllers. This paper formalises the statement above and illustrates some results, including application examples, to demonstrate the advantages of such a novel approach, and to stimulate research on the matter.