> For the complete documentation index, see [llms.txt](https://docs.virtual-flow.org/documentation-vf1/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.virtual-flow.org/documentation-vf1/vflp/untitled-2.md).

# Background  and Principles

Here are described details about the background and the concepts of VFLP which were not covered by [corresponding chapter](/documentation-vf1/principles-and-theory.md) of VirtualFlow in general. This concerns the following topics: 

* [The directory structure](/documentation-vf1/vflp/untitled-2/directory-structure.md)
* [The input & output databases](/documentation-vf1/vflp/untitled-2/untitled-1.md)