1. What is the FTP layer for?
(FAQs/General)

The FTP Layer allows file operations (such as installing Extensions or updating the main configuration file) without having to make all the folders and files writable. This has been an issue on Linux and ...

2. Can Joomla! 1.5 operate with PHP Safe Mode On?
(FAQs/General)

... As files normally are created either by the Joomla! application or by FTP access, the combination of PHP file actions and the FTP Layer allows Joomla! to operate in PHP Safe Mode.  ...