Currently most people look at HCL as a single monolithic app.  This isn't really true, as one of the first things I'd noticed about HCL when I first started using it was that it wasn't programmed like most PHP apps.  Really, HCL setup more like an operating system.  For those into unix type systems (and NT really does fall in this category), you may notice some very simular terms:

The Kernel.
Our Kernel is Aardvark (written by Mike Bird).  Like the kernel in Linux, most everything of an operational nature revolves around this portion of code, which by the way is NOT written in PHP, but Java.  PHP is simply the interface to the rest of the core.

The Core System
This would be the HCL distribution (currently 2.1.3).  Everything at this level supports the core, and interfaces the world to it.

Applications
Currently this would be called modules in HCL.  In the future you'll see modules broken down a bit more into Modules (expansions of the core system), plug-ins (modules which replace core funtionality), and bridges (interfaces to other applications.)  The system is being broken down more to enhance all the areas of HCL, and increase the value of the software. 

My goal is to get HCL to the point where it could be setup as a complete help desk, call center (both on-line and telephone), Pre-sales support, or anything else our users can dream up.  The above description of the system shows how this can be easily done, all it takes is time and effort.

thanks for the explanation, this help us to better understand the soul of HCL