2. The Joomla/Virtuemart technology ecosystem

2.1. Hardware

At the basis, there is the hardware. It is never a bad idea to understand how the hardware of typical, contemporary computer systems works. A good understanding of the Von Neumann architecture, and its contemporary implementation in terms of CPU, memory, disk space and other typical devices will invariably end up proving useful.

2.2. The Kernel

Between the applications and the hardware sits the custodian of shared resources, the kernel. Every operation that lays claim on shared resources, such as memory or hardware devices, ends up in a series of system calls to the kernel. These calls are usually routed through the system libraries, of which the most important is the libc.

Understanding of kernel space versus user space is important background knowledge. Architectural understanding of the Linux system environment, the shell (Bash), the command line tools, and the C language will invariably end up proving useful.

2.3. The LAMP stack

Linux, Apache, MySQL, Php, that is, the LAMP stack, is currently the dominant technology on the web server side of things. These technologies are the foundation for the Joomla/Virtuemart server side technology pack. It is not possible to do useful Joomla/Virtuemart work without a sound understanding of the LAMP stack.

2.4. HTML, CSS, Javascript, Ajax

The days of rich desk desktop clients are mostly over. Whenever possible, the market will favour applications that -- on the client side -- run in the browser, to applications that run directly on the client Operating System (OS).  Joomla/Virtuemart web user interfaces are eventually built on the foundation technologies: HTML, CSS, Javascript, and increasingly on asynchronous javascript remoting, Ajax.

2.5. Joomla

Joomla (http://joomla.org) is a CMS, based on the LAMP stack. To an important extent, your job will consist in installing, configuring, customizing and extending Joomla. You need to be able to figure out the standard Joomla application and library source code.

2.6. Virtuemart

Virtuemart (http://virtuemart.net) is a webshop -- aka, e-commerce infrastructure technology -- that installs as a Joomla extension ("component"). Read as much as you can on how to use and how to configure it. To an important extent, your job will consist in installing, configuring, customizing and extending Virtuemart. You need to be able to figure out the standard Virtuemart application and library source code.

The entire stack of technology bricks in our e-commerce framework is completely open source. From the lowest device driver in the kernel up to the most specialized credit card processing plugin in Virtuemart, the complete source code is available and can be fixed. There are no excuses valid such as "This is a problem with such and such library. We cannot fix it." Wrong. We can always fix it.