Thursday, December 22, 2005

More Fun Speedy Tools: CoralCDN and CoBlitz

I'm sure many Slashdotters have heard of CoralCDN, which is a fairly well-known project that caches web pages. That is, if you add "" to any HTTP request, Coral finds the closest cache node to you and tells it to serve a cached version of that page to you. If it doesn't have a cached version, it goes out and gets it and distributes it all over its network.

[ For example, try going to Look familiar? (note that login information will probably not be preserved for blogger stuff since this is a web cache) ]

[ Note that this is paticularly useful for web site publishers. Publish your page on a slow server and make everything a Coralized link to speed up the whole site. ]

On Coral's web page there is a Firefox extension that will allow you to "Coralize" links (similar to the "GCache" extension). If you go to you can find Grease Monkey scripts that will change every link on a Coralized page to Coralized links (including images). This can be very nice if you're trying to access a web page on a server that is getting hit by lots and lots of server load.

However, it turns out that Coral is hosted by PlanetLab, which is a distributed network that also provides lots of other similar services. You can see a list of their services at

PlanetLab: Services

One of those services is CoDeeN, which is very similar to Coral but is accessed via a standard HTTP proxy instead (so rather than getting an extension to play with your links, you just change your proxy configuration to point to CoDeeN).

However, there are some other pretty neat ones. CoBlitz caught my eye immediately.

CoBlitz is a large file transfer service. That is, by prefixing any URL with "", (without the quotes) you ask CoBlitz to serve that file to you instead of the original URL. (note that CoBlitz can only be used externally for large files; internally (i.e., for CoDeeN nodes) they use it more generally)

So why is this cool? Well, let's say that you have a slow connection to the Internet (for example, over a cable modem) and you are running a little web server serving some large files for friends to download. Well, now you can have CoBlitz serve those files for you. It will not only reduce the draw on your own personal bandwidth but it will provide a much speedier download for your friends.

Plus, services like CoDeeN and Coral (and CoBlitz) are far less sensitive to Internet service outages (due to their collaborative nature).

So I really thought that was cool. I thought some others would like to know.

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