About a zillion years ago (actually it was April last year, but we're talking Web time here) I wrote about Laszlo Systems and its Laszlo Presentation Server for delivering Rich Internet Applications (RIA).

Since those far-off days, Laszlo have made a bold change in its business model: It has gone open source. Laszlo Presentation Server as of October last year became OpenLaszlo under the Common Public License.

What's more, Laszlo has re-engineered its system so that RIAs created with the OpenLaszlo XML-based interface definition language, called LZX, can be delivered either from the OpenLaszlo server (OLS) or compiled by the OLS and delivered by a regular Web server. The latter deployment is called "SOLO" (Standalone OpenLaszlo Output) and can be used as long as the RIA doesn't rely on media types other than SWF, JPG or MP3; persistent connections; SOAP; or XML-RPC (once installed you can find a discussion of PLS vs. SOLO deployment here).

LZX is essentially a meta-description of Flash objects, and the output is a Web page with Flash content. OpenLaszlo's objects are visually elegant and functionally well-designed, which give the LZX-created RIAs a highly professional look and feel - you can see the demos page here.

Version 3.0 OpenLaszlo server has a long list of features including the ability to create virtually "instant" starting RIAs using Laszlo's optimization system called KRANK. OpenLaszlo 3.0 includes a new drawing API and dynamic libraries that allow developers to minimize the application's initial download size and then transfer only the portions of the application the user invokes.

OpenLaszlo is written in Java and requires Java Runtime Environment (JRE) 1.4. The OpenLaszlo Developer Kit requires the Java SDK with the Jakarta Tomcat applet server - in other words, only freeware is required (click here for a useful architectural diagram).

Now you might take a look at LZX and think why isn't there an Integrated Development Environment for this? Well, apparently so did the chaps at IBM so they created an Eclipse plugin for OpenLaszlo.

The combination of OpenLaszlo, Eclipse and the IBM plug-in take building RIAs up a level. Definitely worth checking out if you are building sophisticated Web applications.

Mark Gibbs is a consultant, author, journalist, columnist and blogger.