Tag Archives: geb

Standards as axioms

An important, nay, foundational part of my mental model for how Internet scale systems work (and many other things, in fact), is that I view standards as axioms.

In linear algebra, there’s the concept of span, which is, effectively, a function that takes a set of vectors as input, and yields the vector space spanned by those vectors; the set of all reachable points. Also, for any given vector space you can find a set of axioms – a minimal set of vectors which are linearly independent of each other (orthogonal), but still span the space (note; I use “axioms” here to refer to a normalized set of basis vectors).

So given, say, HTTP and URIs as axioms (because they’re independent), I can picture the space reachable using those axioms, which is the set of all tasks that can be coordinated without any additional (beyond the axioms) a priori agreement; in this case, the ability to exchange data between untrusted parties over the Internet. I can also easily add other axioms to the fold and envision how the space expands, so I can understand what adding the new axiom buys me. For example, I can understand what adding RDF to the Web gives me.

More interestingly (though far more difficult – entropy sucks), I can work backwards by imagining how I want the space to look, then figure out what axiom – what new pervasively deployed standard – would give me the desired result.

As mentioned, I try to evaluate many things this way, and at least where I know enough to be able to (even roughly) identify the axioms. It’s why Web services first set off my bunk-o-meter, because treating HTTP as a transport protocol is akin to replacing my HTTP axiom with a TCP axiom, which severely shrinks the set of possible things that can be coordinated … to the empty set, in fact. Oops!

See also; mu, the Stack, Alexander, software architecture.

Fielding on Web Services (and Waka too)

Michael Radwin reports from ApacheCon 2002 about Roy Fielding‘s presentation on Waka (his planned HTTP 1.1 replacement), and Web services.

There’s a lot of good stuff in Roy’s (PPT) presentation, but Michael appears to get the point Roy was making about Web services backwards. They don’t solve the N^2 problem, they are the N^2 problem. REST’s uniform interface constraint is what drives the complexity of integration to O(N).