I have been tinkering with PHP for a couple days now. It is an interesting language, I am enjoying my experience with it thus far, I can already do some useful things with it. I have implemented a trivial login feature on my secondary pages that stores a cookie for a submitted name, and email address, and then displays your HTTP_USER_AGENT and your remote IP address. No big deal, just learning the language.

But in this tinkering I came across a useful resource. Here is a list of User Agent Strings. I will try and hook the TSV version into my php to display a common name form of the agent you are using to peruse this site.

How can a search engine index 8 billion URL’s? The answer is simple:

PR(A) = (1-d) + d (PR(T1)/C(T1) + … + PR(Tn)/C(Tn))

Well ok, maybe it’s not that simple. But I still find it amazing that the PageRank technology that Google uses can be broken down into a relatively simple one line equation.

If this has peaked your interest, take a look at Larry and Sergey’s article The Anatomy of a Large-Scale Hypertextual Web Search Engine for an explanation of the above algorithm, and some details about how Google works.