Colin's Journal

Colin's Journal: A place for thoughts about politics, software, and daily life.

April 9th, 2003

Visiting the US

According to these figures there are approximately 15-20% fewer people being inspected crossing into the US since before the 11th of September 2001. The figures don’t go back much further (they currently show seasonally adjusted figures, earlier figures show absolute numbers and so aren’t comparable). I wonder how much of this drop can be attributed to economic woes versus a drop in the desire to either leave (residents returning count in the inspection stats) or enter the US?

Contrast (if not comparison) with the UK is difficult because the immigration situation is more complex. EU nationals entering and leaving the UK are not “inspected” and leave no paper trail (you generally just wave your passport at someone). Travel within the UK’s common area (Isle of Man, etc) also confuse things. Despite this there is an easy to read press release here that covers the number of overseas residents entering the UK. The situation seems to be broadly one of no change:

The number of overseas residents arriving in the UK during the period December 2002 to February 2003, seasonally adjusted, was 16 per cent higher than in the same period a year earlier. However, it should be noted that the end of 2001 and early 2002 were affected by the September 11th terrorist attacks in the USA. Comparing December 2002 to February 2003 with the same period two years earlier (December 2000 to February 2001), there was an increase of one per cent in the number of overseas residents arriving in the UK.

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April 9th, 2003

More musing on publish-subscribe

This is a follow on from my thoughts yesterday regarding whether a publish-subscribe model for RSS would be useful.

The more I think about it the less use I see for distributing RSS via a publish-subscribe service, like the one I did an initial specification for yesterday. While it could be considerably more efficient to distribute weblog changes via such a service, I don’t see a compelling reason to make the investment required in software to support such services. The result for the end user is the same as it is today, it just takes less bandwidth.

While the rss feed for this weblog is by far the most requested file on, it’s very low down on the bandwidth usage (less than 2%). From a client perspective the extra overhead of requesting and parsing RSS files versus talking to a subscription server is minimal, and with web based RSS aggregators the overhead disappears entirely (the host of the aggregator takes the load instead).

There is one use case that I can think of however which may benefit from such a publish-subscribe method. Imagine if most web pages had a ‘Watch This Page’ button on them somewhere (similar to the orange XML button). Selecting this button would subscribe the user, through there chosen subscription service, to notifications of changes to that page. Instead of having to remember to check back on pages occasionally for changes you could just click on this button, and you will now be notified if it changes. Would this be useful?

The infrastructure required to deploy such a system isn’t that difficult to roll out. The button would be a link to a file (potentially generated dynamically) which would contain the resourceID for this page, and the URL for the publishing notification server. On selection the browser would download this file, send it to a program installed locally, which in turn sends the details to the user’s chosen subscription notification server.

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Copyright 2015 Colin Stewart

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