NetKernel News Volume 3 Issue 29

June 28th 2012

What's new this week?

• Repository Updates
• Proposal to Update H2 to 1.3.x / Generated Keys
• ROC Concept Maps
• Gone Social

Catch up on last week's news here

Repository Updates

The following update is available in the NKEE and NKSE repositories...

• json-core 1.7.1
  • Adds mode to optionally ignore root element in active:JSONFromXML

Proposal to Update H2 to 1.3.x / Generated Keys

Chris Cormack and I have been discussing the potential of shipping a library update for the H2 embedded DB module. Its currently back on an old 1.2.x release and could be moved forward to 1.3.x - however we've seen some potential snags which we discuss here...

http://www.1060.org/nk4um/topic/894/index

Do you use the H2 library? Do you have a strong opinion one way or another about updating? We have identified that a workaround release to apposite would be required if we were to ship it as an update - but other than the IDENTITY() function, we have not seen any noticeable regression. Thoughts?

Also Chris has proposed that we augment the HDS result-set from mod:db to provide a new branch in the tree /resultset/generatedKeys to hold the generated keys reported by the JDBC driver. As a new branch in the tree this won't affect existing tree-based iterations of /resultset/row and I would hope falls into the classic pattern of "extending a tree with a new branch doesn't disturb legacy". Anyone have strong objections to this enhancement? Please add your comments to that forum thread.

ROC Concept Maps

Tony has posted a new blog entry which offers a graphical way of visualizing and relating the core concepts of ROC/NK...

http://durablescope.blogspot.co.uk/2012/06/roc-concept-maps.html

Hopefully this adds another perspective and highlights that the core ROC abstraction is compact and simple.

Of course the elephant that sits in the middle of the room is: "Resource".

The concept of "resource" is the core "new idea". It is the philosophical notion that all information has the potential for existence but that this potential is necessarily abstract and intangible.

We can't touch resources, we can only touch representations of resources.

To computer science this is a dramatically alien idea but it has been around in Physics and Philosophy for a very long time. You'll already know that this has echoes of the "Platonic Forms", but perhaps some more practical examples come from Physics...

In Maxwell's great unifying work on Electricity and Magnetism - he showed that the physical and measureable magnetic field is actually and fundamentally defined by something called the magnetic vector potential (A) through the relation: B = ▽ x A - which says, the magnetic field is the curl of the magnetic vector potential. So, you can measure B but you can never touch or measure A - it is the abstraction that underpins the physics.

Equally in quantum mechanics you'll have heard of the wavefunction. Well the wavefunction is a probability density function but you can never measure it since fundamentally all wavefunctions (Ψ) are imaginary (truly all wavefunctions consist of imaginary numbers). However the physical representation of the state of a particle is determined by the value of the "square of the wavefunction" (Ψ²). Just like with A, you can never touch or measure Ψ.

So, as with Platonic Forms and fundamental Physics, in ROC we can never touch resources. But what we can do is conspire to construct and compose address spaces such that the interplay of resolvable resource identifiers leads to a solution in which concrete representations can be reified (touched).

As Tony's diagrams show - when a request is made for a resource, we are destined never to actually touch the resource, but to be resolved to an endpoint that can provide us with a representation of the state of the resource. Like trying to grasp your reflection in a pool of water.

With this in mind you can also see why the most common category of endpoint is called the "Accessor". Its not an arbitrary name we made up on a whim. It really is saying something formal - it is the physical mechanism by which you may access an abstract resource. Hence: "Accessor".

Gone Social

As a northern lad from the land where "just say nowt" is the default, I have to say that tweeting doesn't come naturally. To date my use of the medium has been strictly professional - even to the point of appearing rude with a no compromise "no follow" policy.

Well something snapped this week - maybe it was having recently had a week in LA - did the unrelenting and oppressive optimism of daily sunshine push me over the edge? I don't know. But I decided it was time to open up a bit on the social spectrum. Is there a Beaufort scale of social networking?

1. No tweets, occasional reader, as silent as a downy feather landing on an oiled puddle
2. Light, tweets like a soft whisper into a coiled ear-trumpet filled with cotton wool
3. Light to Moderate, tweets like small raindrops falling on a tambourine in a Whitsun parade
4. Moderate, tweets like a Spanish hamster wearing small castanets running around a wheel.
5. Strong, tweets like a team of carpenters erecting a lean-to shed during a screw-driver shortage.
6. Gale Force, tweets like a Welsh-colliery steam railway train running over rusty points on a narrow-gauge track in a downpour.
7. Hurricane Force, tweets like incurable tinitus induced by body surfing at the front of the crowd to Iggy and the Stooges playing Kill City for 4 hours at Glasgow Barrowlands.

So I shall continue to keep the official accounts with a typical 1.5 rating on the scale. But with my new account, which is an alternate representation of @pjr1060 and so is called @transrept, I'm aiming to get myself to the Whitsun tambourine scale with light whimsy, moderate banter, light follows, occasional images and moderate displays of personality.