Wednesday, 26 September 2007

Aglets – a new way for mobile computing

I must have been messing around at the back of the class recently, because I have only just heard of aglets – a portmanteau word created from agent and applet – that run with distributed DB2 databases.

A mobile agent is an exceptionally clever piece of software that can migrate during execution from machine to machine in a heterogeneous network. Once it arrives on a new machine, the agent then interacts with service agents (that are permanently located on that machine) and other resources to perform its mission. So why would you want to use this kind of technology? Well the answer, as so often, is improved performance. Because the agent moves to the remote machine and performs a search (or whatever) and sends across the network the results, there is a huge reduction in the amount of data that uses the network and therefore every other network-related application isn’t slowed down – hence the improved performance. Any other method would involve large amounts of data from one computer being copied to another, and then searched (or whatever) there. Using aglets moves the processing to the computer on which the data resides – so, therefore, much less network traffic is necessary.

So how do you get hold of aglets? IBM’s Tokyo Research laboratory has created the Aglet Workbench, and the package can be downloaded from

The mobile agents are 100% pure Java. The Java Aglet API (J-APPI) is the interface used to build aglets and their environments. The API is platform agnostic, but it does require JDK 1.1 or higher to be installed for it to run. There is an agent server, which is called Tahiti, and this (by default) uses port 4434. Transferring agents between computers is achieved using ATP (Aglet Transfer Protocol).

It is definitely an interesting and useful development.

And for people who enjoy quiz nights – an aglet is also the little piece of plastic (or, perhaps, metal) at the end of a shoelace (usually) that stops the lace from unravelling.

My thanks to Nikola Lazovic, a regular contributor to Xephon's ( DB2 Update journal, for drawing aglets to my attention.

And on a different, but related note… WebSphere Update, also from Xephon, is looking for new authors to broaden its base of contributors. If you work with WebSphere and you have discovered something you wished you’d known before you started, or you’ve implemented something useful that others could benefit from, please contact me on

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