Alan’s blog

It is the end of the summer, the September rush starts (actually at the end of August) and on Friday I’ll be setting off on the ferry and be away from home for all of September and October   Of course I didn’t manage to accomplish as much as I wanted over the summer, and didn’t get away on holiday … except of course living next to the sea is sort of like holiday every day!  However, I did take some time off when Miriam visited, joining her on cycle rides to start her training for her Kenyan challenge — neither of us had been on a bike for 10 years!  Also this last weekend saw the world come to Tiree when a group of asylum seekers and refugees from the St Augustine Centre in Halifax visited the Baptist Church here — kite making, songs from Zimbabwe and loads of smiling faces.

In September I also hand over departmental personnel duty (good luck Keith ).  I’d taken on the HR role before my switch to part-time at the University, and so most of it stayed with me through the year (Note, if you ever switch to part-time, better to do so before duties are arranged!). Not sorry to see it go, the people bit is fine, but so much paper filling!

… and beginnings … in September (next week!) I also start to work part-time with Talis.  Talis is a remarkable story.  A library information systems company that re-invented itself as a Semantic Web company and now, amongst other things, powering the Linked Data at data.gov.uk.

I’ve known Talis as a company from its pre-SemWeb days when aQtive did some development for them as part of our bid to survive the post-dot.com crash.   aQtive did in the end die, but Talis had stronger foundations and has thrived¹.  In the years afterwards two ex-aQtive folk, Justin and Nad, went to Talis and for the past couple of years I have also been on the external advisory group for their SemWeb Platform.  So I will be joining old friends as well as being part of an exciting enterprise.

1. Libraries literally need very strong foundations.  I heard of one university library that had to be left half empty because the architect had forgotten to take account of the weight of books.  As the shelves filled the whole building began to sink into the ground. [back]

Names and naming have always been a big issue both in computer science and philosophy, and a topic I have posted on before (see “names – a file by any other name“).

In computer science, and in particular programming languages, a whole vocabulary has arisen to talk about names: scope, binding, referential transparency. As in philosophy, it is typically the association between a name and its ‘meaning’ that is of interest. Names and words, whether in programming languages or day-to-day language, are, what philosophers call, ‘intentional‘: they refer to something else. In computer science the ’something else’ is typically some data or code or a placeholder/variable containing data or code, and the key question of semantics or ‘meaning’ is about how to identify which variable, function or piece of data a name refers to in a particular context at a particular time.

The emphasis in computing has tended to be about:

(a) Making sure names have unambiguous meaning when looking locally inside code. Concerns such as referential transparency, avoiding dynamic binding and the deprecation of global variables are about this.

(b) Putting boundaries on where names can be seen/understood, both as a means to ensure (a) and also as part of encapsulation of semantics in object-based languages and abstract data types.

However, there has always been a tension between clarity of intention (in both the normal and philosophical sense) and abstraction/reuse. If names are totally unambiguous then it becomes impossible to say general things. Without a level of controlled ambiguity in language a legal statement such as “if a driver exceeds the speed limit they will be fined” would need to be stated separately for every citizen. Similarly in computing when we write:

function f(x) { return (x+1)*(x-1); }

The meaning of x is different when we use it in ‘f(2)’ or ‘f(3)’ and must be so to allow ‘f’ to be used generically. Crucially there is no internal ambiguity, the two ‘x’s refer to the same thing in a particular invocation of ‘f’, but the precise meaning of ‘x’ for each invocation is achieved by external binding (the argument list ‘(2)’).

Come the web and URLs and URIs.

Fiona@lovefibre was recently making a test copy of a website built using Wordpress. In a pure html website, this is easy (so long as you have used relative or site-relative links within the site), you just copy the files and put them in the new location and they work Occasionally a more dynamic site does need to know its global name (URL), for example if you want to send a link in an email, but this can usually be achieved using configuration file. For example, there is a development version of Snip!t at cardiff.snip!t.org (rather then www.snipit.org), and there is just one configuration file that needs to be changed between this test site and the live one.

Similarly in a pristine Wordpress install there is just such a configuration file and one or two database entries. However, as soon as it has been used to create a site, the database content becomes filled with URLs. Some are in clear locations, but many are embedded within HTML fields or serialised plugin options. Copying and moving the database requires a series of SQL updates with string replacements matching the old site name and replacing it with the new — both tedious and needing extreme care not to corrupt the database in the process.

Is this just a case of Wordpress being poorly engineered?

In fact I feel more a problem endemic in the web and driven largely by the URL.

Recently I was experimenting with Firefox extensions. Being a good 21st century programmer I simply found an existing extension that was roughly similar to what I was after and started to alter it. First of course I changed its name and then found I needed to make changes through pretty much every file in the extension as the knowledge of the extension name seemed to permeate to the lowest level of the code. To be fair XUL has mechanisms to achieve a level of encapsulation introducing local URIs through the ‘chrome:’ naming scheme and having been through the process once. I maybe understand a bit better how to design extensions to make them less reliant on the external name, and also which names need to be changed and which are more like the ‘x’ in the ‘f(x)’ example. However, despite this, the experience was so different to the levels of encapsulation I have learnt to take for granted in traditional programming.

Much of the trouble resides with the URL. Going back to the two issues of naming, the URL focuses strongly on (a) making the name unambiguous by having a single universal namespace;  URLs are a bit like saying “let’s not just refer to ‘Alan’, but ‘the person with UK National Insurance Number XXXX’ so we know precisely who we are talking about”. Of course this focus on uniqueness of naming has a consequential impact on generality and abstraction. There are many visitors on Tiree over the summer and maybe one day I meet one at the shop and then a few days later pass the same person out walking; I don’t need to know the persons NI number or URL in order to say it was the same person.

Back to Snip!t, over the summer I spent some time working on the XML-based extension mechanism. As soon as these became even slightly complex I found URLs sneaking in, just like the Wordpress database The use of namespaces in the XML file can reduce this by at least limiting full URLs to the XML header, but, still, embedded in every XML file are un-abstracted references … and my pride in keeping the test site and live site near identical was severely dented¹.

In the years when the web was coming into being the Hypertext community had been reflecting on more than 30 years of practical experience, embodied particularly in the Dexter Model². The Dexter model and some systems, such as Wendy Hall’s Microcosm³, incorporated external linkage; that is, the body of content had marked hot spots, but the association of these hot spots to other resources was in a separate external layer.

Sadly HTML opted for internal links in anchor and image tags in order to make html files self-contained, a pattern replicated across web technologies such as XML and RDF. At a practical level this is (i) why it is hard to have a single anchor link to multiple things, as was common in early Hypertext systems such as Intermedia, and (ii), as Fiona found, a real pain for maintenance!

1. I actually resolved this by a nasty ‘hack’ of having internal functions alias the full site name when encountered and treating them as if they refer to the test site — very cludgy! [back]
2. Halasz, F. and Schwartz, M. 1994. The Dexter hypertext reference model. Commun. ACM 37, 2 (Feb. 1994), 30-39. DOI= http://doi.acm.org/10.1145/175235.175237 [back]
3. Hall, W., Davis, H., and Hutchings, G. 1996 Rethinking Hypermedia: the Microcosm Approach. Kluwer Academic Publishers. [back]

Just been at a public meeting about imminent cuts in the school here on Tiree. In a small school like this (120 pupils) losing several posts isn’t just a matter of shrinking slightly, but means that whole subjects, such as French, drop off the curriculum.

There are two issues here.  One is for the island and other small communities, as the funding formulae assume class sizes that are untenable in a small school; that is making sure the cuts that come, and we know they must, are applied fairly.

The second is  wider, remembering that all parties in the election promised to protect ‘front line services’; this is part of  a cut across all education provision in the region – everywhere there are less teachers … and this is before the harshest budget cuts begin.

Many people already knew this was happening, but for those that don’t — I am now officially a part-time university academic.

Now this does not mean I’m going to be a part-time academic, quite the opposite.  The reason for moving to working part-time at the University is to give me freedom to do the things I’d like to do as an academic, but never have time.  Including writing more, reading, and probably cutting some code!

Reading especially, and I don’t mean novels (although that would be nice), but journal papers and academic books.  Like most academics I know, for years I have only read things that I needed to review, assess, or comment on — or sometimes in a fretful rush, the day before a paper is due, scurried to find additional related literature that I should have known about anyway.  That is I’d like some time for scholarship!

I guess many people would find this odd: working full time for what sounds like doing your job anyway, but most academics will understand perfectly!

Practically, I will work at Lancaster in spurts of a few weeks, travel for meetings and things, sometimes from Lancs and sometimes direct from home, and when I am at home do a day a week on ‘normal’ academic things.

This does NOT mean I have more time to review, work on papers, or other academic things, but actually the opposite — this sort of thing needs to fit in my 50% paid time … so please don’t be offended or surprised if I say ‘no’ a little more.  The 50% of time that is not paid will be for special things I choose to do only — I have another employer — me

Watch my calendar to see what I am doing, but for periods marked @home, I may only pick up mail once a week on my ‘office day’.

Really doing this and keeping my normal academic things down to a manageable amount is going to be tough.  I have not managed to keep it to 100% of a sensible working week for years (usually more like 200%!).  However, I am hoping that the sight of the first few half pay cheques may strengthen my resolve

In the immediate future, I am travelling or in Lancs for most of February and March with only about 2 weeks at home in between, however, April and first half of May I intend to be in Tiree watching the waves, and mainly writing about Physicality for the new Touch IT book.

… and in the afternoon, the mountains of Jura ethereal over the sea

Morning sky looking south from Tiree towards Jura and the Ross of Mull

Just been out to see the wind turbine at Ruaig.  They were delivering the parts when I was on the Island for a few days in November, but first time I’ve seen it close up since they put it together.

The Royal Mail has had a lot of bad press recently with strikes, postal delays and ‘modernisation’. However, it is easy to forget the revolutionary nature of the “Penny Post“: one price and one service to deliver anywhere in the country.  Living  in Tiree, one of the western Scottish islands, this is particularly pertinent.  Many carriers do not deliver here or only do so at a higher rate; those that do are often delayed waiting for the ferries, but so long as the plane comes in so does the post.

Our shower was leaking water and on Friday at around 12:42pm we ordered spare parts from Shower-Warehouse.  I had assumed that they would not arrive before I set off back to Lancaster on Tuesday morning and so it would be Christmas before I could actually do the repair.

But, at 1pm today, they were delivered

So top marks for both the Royal Mail and Shower-Warehouse and may modernisation never change the wonder of universal post.

I’m on the ferry on my way to Tiree.  I’ve not been back home for nearly 8 weeks and have a long weekend before heading back down to Lancaster until Christmas.  Since I left in mid September I’ve slept in 19 different places and had 23 moves between places; however, my main home has been the camper van, a Ford Transit Auto-Sleeper Duetto, small enough to manoeuvre easily, but with everything on board from cooker and fridge to its own toilet and shower!

I’ve also not blogged since I was last at home. I have a half-written entry from Paris, I was at a lecture by John Searle in Eindhoven and really want to write about that, and I also need to write a retrospective on my sabbatical year, but not had a moment; indeed on my office desk is an iPhone, which has sat waiting to be unpacked for the last 2 months, no time even to play :-/

Perhaps over the next few days I can catch up with the half-written blogs amongst the unanswered email, overdue papers, and pressing admin; and also take some time to appreciate the sea and wild wind.

Hard work running this morning; high tide so soft sand underfoot and stiff breeze off the sea (Met Office says 29 mph with gust of 39 mph), but, so glorious: sun shining on the running wind-driven waves. Perfect weather for those involved in the traction kiting on Gott Bay.