System virtual folders

In Windows there are a number of virtual folders that are presented as being part of the file system (also known as the shell namespace). The Desktop folder is an example of a virtual folder. It is a folder that can contain real files (e.g. if you save a document to the desktop, it is stored in a real disk folder) but it also contains virtual items that don't correspond to a real file on a disk (for example, the desktop contains a link to the Recycle Bin, and to the Computer folder).

When you navigate to a virtual folder in the shell namespace, the Lister acts as a container and hosts an instance of Explorer to provide the display. The advantage of doing this is that it lets you navigate the entirety of the shell namespace from within Opus. Many third-party developers have written what are called shell namespace extensions. For example, if you connect your mobile phone or digital camera to your PC, you are often able to copy files to and from it in Explorer. This functionality is implemented by a small piece of software that extends the shell namespace and provides access to an otherwise proprietary device. If Opus did not support hosting Explorer for these third-party folders, you would be forced to leave Opus and actually use Explorer to access them - and we wouldn't want you to have to use Explorer any more than necessary!

The disadvantage of hosting Explorer is that to Opus, the folder appears as a "black box". Opus literally has no idea what the contents of the folder are - even the display is provided by Explorer, with Opus doing no more than providing a place for Explorer to put its window. Therefore much of the native Opus functionality is unavailable in these virtual folders.

For that reason, Opus provides a native implementation of several virtual folders. This means that you can use Opus features like Folder Formats, Power mode or Preferences settings like background images in some commonly used virtual folders. The virtual folders currently supported by Opus are:

• Desktop: The Desktop is the root of the shell namespace. It displays the merged contents of two disk-based folders (your personal desktop folder, and the All Users desktop folder) as well as links to various virtual folders like Recycle Bin, Network, Libraries, etc. The native view provided by Opus can be configured from  the Folders / Virtual Folders Preferences page - you can choose exactly which virtual folders are displayed on the Desktop.
• Computer: The Computer folder (or in Windows XP, My Computer) displays the disk drives and devices installed in your system. By default empty disk drives (e.g. a DVD drive without a disc in it) are not displayed - you can change this from the Folders / Virtual Folders Preferences page.
• CD Burning: Opus provides a native view of writeable CD and DVD disks when using the Windows CD burning system (with staged burning only - the LiveFS packet writing system is treated like a normal disk folder).

Some virtual folders, like Computer, are purely virtual - they don't correspond to a real folder on disk. Other folders, like the C:\Windows\Fonts directory, are real disk folders that have a virtual "overlay" when displayed in Explorer. The options on the Folders / Virtual Folders Preferences page let you control how Opus handles this sort of directory - if desired, you can choose to have Opus display the underlying "real" folder rather than the virtual presentation.