ENTRIES TAGGED "control"

Why Feedback?

Maintaining a desired behavior

In two previous posts (Part 1 and Part 2) we introduced the idea of feedback control. The basic idea is that we can keep a system (any system!) on track, by constantly monitoring its actual behavior, so that we can apply corrective actions to the system’s input, to “nudge” it back on target, if it ever begins to go astray.

This begs the question: Why should we, as programmers, software engineers, and system administrator care? What’s in it for us?

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The Feedback Principle

Gracefully maintain a desired value in the presence of uncertainty and change

In a previous post, we introduced the basic feedback concept. Now it is time to take a closer look at this idea.

Feedback is a method to keep systems on track. In other words, feedback is a way to make sure a system behaves in the desired fashion. If we have some quality-of-service metric in mind, then feedback is a reliable method to ensure that our system will achieve and maintain the desired value of this metric, even in the presence of uncertainty and change.

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Distributed resilience with functional programming

Steve Vinoski on when to make the leap to functional programming.

Functional programming has a long and distinguished heritage of great work — that was only used by a small group of programmers. In a world dominated by individual computers running single processors, the extra cost of thinking functionally limited its appeal. Lately, as more projects require distributed systems that must always be available, functional programming approaches suddenly look a lot more appealing.

Steve Vinoski, an architect at Basho Technologies, has been working with distributed systems and complex projects for a long time, first as a tentative explorer and then leaping across to Erlang when it seemed right. Seventeen years as a columnist on C, C++, and functional languages have given him a unique viewpoint on how developers and companies are deciding whether and how to take the plunge.

Highlights from our recent interview include:

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