A blog about software – researching it, developing it, and contemplating its future.

Conscientious Software, Part 1: Allopoiesis and Autopoiesis

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Recently some Sun researchers wrote a very interesting paper about the future evolution of software. The paper seeks to characterize a new type of software, which they term “conscientious”. I want to dig into this concept a bit.

This will be a multi-post series; this first post lays the groundwork, then the subsequent posts will delve into some further implications of the basic concepts.

This post will make much more sense if you read their paper first; otherwise, hang on 🙂 Their paper is very much a manifesto, in the sense that it aggressively commingles concepts from biology, engineering, and computer science to propose a very ambitious and not-fully-understood thesis. So, this post is going to do that too, and conceptual rigor be damned. It’s brainstorming time.

Conscientious software might be described (paraphrasing their paper heavily) as software which has a currently unknown degree of self-awareness, in the sense that it has the ability to test itself, to analyze its own functioning, to address external or internal malfunctions appropriately, and to maintain its operation under a variety of adverse conditions. And, of course, to actually do some job that we consider valuable.

There are two kinds of systems they talk about extensively. These are allopoietic systems and autopoietic systems. The technical definitions here come from biology, but I’ll paraphrase heavily and just say that an autopoietic system creates itself, sustains itself, and produces itself, whereas an allopoietic system is externally created and produces something other than itself.

An example they give is the distinction between a living amoeba and a watch. An amoeba consists of a large number of cellular structures and chemical processes. A living amoeba is a dynamic system — its continued existence depends on its active metabolism, by which it takes in nutrients, processes them, excretes material toxic to it, seeks out hospitable environments, and avoids dangerous ones. All the metabolic cycles and other processes that constitute the amoeba are primarily oriented towards self-sustainment.

A watch, on the other hand, has almost no ability to sustain itself. Its sole purpose is to tell time, and that purpose is only useful to the users of the watch, not to the watch itself. If the watch malfunctions, it must be repaired externally.

What does this have to do with software? They claim — and I think I agree — that software needs to develop in a more autopoietic direction. Fragile software, with frequent malfunctions, tricky configuration, and inadequate self-monitoring and self-repair capabilities, is increasingly hard to scale to larger and more complex functions. Yet we clearly want software to be capable of more than it currently is. Autopoiesis is a very thought-provoking concept when considering how to design such self-sustaining systems.

They make another point, which is that a purely autopoietic system — one which is only concerned with self-sustainment — is of little value to us. We want a system which can both sustain itself and produce something valuable. Their paper draws a picture of an autopoietic system containing an allopoietic core — the self-sustaining system devotes a large part of its resources to solving specific, externally defined problems.

This is all terribly abstract. What would such a system look like? Are we talking about some kind of muzzy fuzzy genetically engineered software? What are some examples of autopoietic software today?

They start with garbage collection as an example of an autopoietic software function. In some sense, memory is the environment in which software exists. As software runs, it populates that memory. Without lots of careful management, the memory can easily become cluttered with no-longer-used but not-yet-deallocated objects. It’s no big stretch to consider garbage objects as waste products of the software’s metabolism. (Well, OK, it is a stretch, but like I said, we’re brainstorming here.)

Garbage collection was originally developed to enable LISP programs to be developed in the way that was conceptually cleanest — in other words, in a largely functional, allocation-intensive style — without complicating them with memory reclamation logic. Externalizing the garbage collection code meant that the LISP program itself could more or less just do its job, with the underlying metabolism of its environment responsible for cleaning up its waste.

Another example (mine, not theirs), and probably one of the most well-known (or at least well-documented) large-scale examples, is Google’s infrastructure. Google has developed numerous systems — the Google File System, the BigTable large-scale database and the Chubby lock system — that are inherently widely distributed and fault-tolerant. These systems actively monitor themselves, replicate their data around failed components, and generally self-manage on top of a widely distributed pool of faulty servers. It is even less of a stretch to think of these systems as implementing a metabolic environment for user programs that is composed from cells (servers) that routinely die and are replaced, while the entire system has a dynamic, self-sustaining continuity. (I’m sure many Google admins would laugh very hard at the phrase “self-sustaining” here, but nonetheless these systems do internally monitor and repair themselves.)

The allopoietic component of the Google environment is the applications that actually run on the underlying autopoietic Google services. These applications can (mostly) ignore the details of the hardware they run on and the storage they use; they can simply consume the resources they need (in both persistent storage and CPU) to perform their job.

OK. So that’s autopoiesis and allopoiesis as applied to software as we currently know it. Next post: allopoiesis as the foundation of autopoiesis.


Written by robjellinghaus

2007/09/07 at 03:22

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