Skip to main content

Turning Turing upside down

I am probably not alone in visualizing Turing's Universal Machine as a little animacule walking over a linear landscape of ones and zeros:

Turing-1

The great innovation of thinkers such as Turing and others was to reduce the complex world of algorithms and functions into something simple and elemental: all computable functions can be thought of as state machines operating over a large collection of ones and zeros, presence and absence.

There are arguably many differences between a Turing Universal Machine and a modern browser (quite apart from the fact that, being a Javascript interpreter makes a browser a TUM). But for me, one of the most striking differences is that where a TUM is an animacule in a universe of one and zeroes, the browser is an animacule in a universe of HTML, CSS, HTTP and so on.

The browser understands a different world than Turing's computer. Were we to draw a browser as an animacule, it should look like:

Browser-1

There are similarities, and if you were to look at it from the perspective of a binary TUM, you would be hard put to see a significant difference between a browser and a regular TUM. But that would be missing an essential difference.

The browser understands a different world than the TUM because the concepts that underlie its state machine are concepts from the world of the web, not the world of ones and zeros. Its semantic engagement with the world is different; arguably higher level than the binary TUM. The browser stands on the shoulders of the binary TUM, but nevertheless reaches higher.

What, one may ask, would the level above the browser's level look like? And is there an infinite stack of levels waiting for our discovery?

Popular posts from this blog

Comments Should be Meaningless

This is something of a counterintuitive idea: Comments should be meaningless What, I hear you ask, are you talking about? Comments should communicate to the reader! At least that is the received conventional wisdom handed does over the last few centuries (decades at least). Well, certainly, if you are programming in Assembler, or C, then yes, comments should convey meaning because the programming language cannot So, conversely, as a comment on the programming language itself, anytime the programmer feels the imperative to write a meaningful comment it is because the language is not able to convey the intent of the programmer. I have already noticed that I write far fewer comments in my Java programs than in my C programs.  That is because Java is able to capture more of my meaning and comments would be superfluous. So, if a language were able to capture all of my intentions, I would never need to write a comment. Hence the title of this blog.

Action at a distance

We are currently writing our first draft of the SOA Reference Architecture. Everyone is very busy doing their bit. My current section is on the Real World Effect of using a service. The RA is really an abstract architecture: we are not focusing on things like SOAP, or any of the other 60+ Web service specifications out there. We are trying to get at the essence of makes SOA special and how it can be made to work. It is a pretty basic aspect of services that we are trying to get something to happen: buy a book, get the weather forecast whatever. In other words: its action at a distance. I am communicating with you in the hope that we can get some mutual benefit. This already distinguishes SOA from the Web, whose basic abstraction is to acquire a representation of a resource will be rendered locally for human consumption. Actions are not inherently about representations, they are about changing the world - one book at a time. Action itself is a very difficult concept to get hold of. It ...

Organizing principles for services

One of the questions that comes up from time to time is how to define your services. This has come up for me in two independent fora: within the OASIS Service Oriented Architecture work and in the context of human provided services, for example at Genietown . In the work on the SOA Reference Model we decided that "services are the mechanism by which needs and capabilities are brought together"; i.e., its about needs and capabilities to satisfy those needs, and the access mechanism. However, this still begs the question somewhat. In the domain of human services, where the services are things like "building a home", "walking the dog", "taking care of my elderly parents"; it gets even fuzzier. Sometimes a service seems to organized around the person offering the service, for example, an architect, or a doctor. Sometimes the service is organized around a particular kind of product, such as doors or skylights. At other times, the service is organize...