Wednesday, October 29, 2003

THE CURSE OF CACHING

From the many kind and much appreciated emails that I receive, I gather that this blog is continually getting new readers. For their benefit, therefore, I want to repeat some old advice. There are TWO reasons why logging on to this blog may not give you any recent postings. The first is when blogger.com is having one of their frequent hiccups and whatever I attempt to upload just does not appear. Such problems generally clear up after about 12 hours but not always. There are two blogspot sites that I have not been able to post to for months. I cannot add to them, edit them or even delete them. They just sit there frozen in time. There is no reason why the same thing could not happen to this site. This site too may one day grind to a halt for good.

The second holdup is because of caching. In between any reader and the original site on which a file is held are a large number of servers and any one of these can decide to “cache” a file -- i.e. they see that a file is often called for so hold a copy of it themselves rather than go back to the original source all the time. That is all fine and dandy if the cache is cleared every few hours -- as it should be. But that does not always happen. Sometimes a file sits unchanged in somebody’s cache for days. In such cases, if your file request happens to go through that server, you will get a days-old copy of this blog rather than the current version.

There are 3 solutions to the problem. The first solution is in my hands. I need to put cache-busting metacode into every file I upload. I mostly do that but even that often does not work. The second solution is in the reader’s hands. You can send a “cache bypass” command from your keyboard. Just hit the “Ctrl” and F5 keys at the same time. But that does not always work either. So that is why I have mirror sites -- second and third copies of everything posted on this blog. So if you are not getting anything recent here click on one of the mirror sites listed under “My other sites” toward the top of the green column to the left. The mirrors sometimes get cached too, of course, but you would have to be really out of luck for them all to be cached at the same time. Happy reading!

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FROM BROOKES NEWS

The Bush Presidency casts a funereal shadow across the Democrats. If the GOP were to increase its black support by about 5 percentage points in the 2004 election while repeating its California success with women and Hispanics, the Dems will end up as burnt toast.
The 2003 Nobel Prize in economics. Why statistics fails to captures human economic activity.
Journalist bigotry among the media's Bush-haters. By lavishing undeserved praise on Barker the venomous Ramsey of the 'Sydney Morning Herald' did draw attention to what passes for learning and intellect among our self-righteous lefty journalists.
Immigration, jobs and growth. The accusation that immigration destroys jobs is a common economic fallacy.

Details here

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