Some people have asked what this new extension pack is in Oracle VM Virtualbox 4.0 and how it's different from 3.2 and earlier releases.

The extension pack is a restructuring of how Oracle VM VirtualBox is installed.

Please take a look at http://virtualbox.org and read up on what the product install looked like prior to 4.0, you'll see the following :

There were 2 versions to download :

- Oracle VM VirtualBox (open source edition) OSE - download of the source tarball with a GPL license + compile needed to run.

- Oracle VM VirtualBox PUEL (personal use/eval license) - download of an installable binary with a number of additional non-gpl license drivers, usb2, sata, pxe boot for e1000, vrdp server etc., all built in to the install. This contained the OSE edition + additional drivers with the installer.

Customers could purchase an enterprise software license for the latter version.

To make it easier to build and release additional drivers, they have been separated out and are now installed through an "extension pack" starting with Oracle VirtualBox version 4.

This extension pack is still licensed the same way as in every prior version, via a PUEL license or with the ability to purchase a commercial license. It is now also possible for other companies or users that want to add extensions to do so by creating a similar extension pack -- and there's no need to do a new release of the entire product to do so.

So it's a more flexible structure for installing VirtualBox and drivers and allows for more modular additions. The source code of Oracle VM Virtualbox is, of course, still available just like in 3.x, for 4.0. Like 3.x, not for the additional drivers which are now in the extension pack.