Select Help → System Info from the drop-down menu on the Back-end of your Joomla! installation.
The System Info screens provides useful information about your host server environment, including operating system, PHP settings, and directory access settings. You can navigate to five different screens: System Info, PHP Settings, Configuration File, Directory Permissions, and PHP Information. Each screen provides detailed information about that aspect of your Joomla! web site.
This information is very helpful when you are troubleshooting setup problems. Note that none of these settings can be changed from these screens. That must be done in other places, depending on the specific setting. The settings in the Configuration File screen can be changed from the Global Configuration screen. The other settings shown here depend on your host server configuration and cannot be changed from inside Joomla!
This screen shows information about the operating environment for your Joomla! web site, as follows:
These screen shows the Relevant PHP Settings information. If any of these is highlighted as incorrect should be taken care of to rectify the situation.
This screen shows the contents of the current Joomla! configuration.php file which is stored under the main joomla_root/ directory. This file is created for you automatically when you first install Joomla! and where most changes of the Global Configuration section of Joomla! are recorded. Please note that none of the settings can be changed from this page. Use the Global Configuration to see more information about these settings and to make changes.
This screen shows a list of the directories that the webserver should have write access to. Please note that all directories listed on this page should say Writable. If not, you may need to change the permissions to be able to install and use Joomla! successfully.
This screen displays the full configuration of the PHP server side scripting language that Joomla! runs on, together with all the associated system information that goes towards the creation of the web server. It is the output of an integrated php.info script built into Joomla!.
PHP is installed, and runs on the server (hence the server side above), and therefore all the settings are made on the server. The visitor to the web site does not need to have anything special running on their local machine in order to view or use any of the extra functionality that PHP gives to the web site.
All the settings that are ever likely to be needed are displayed here. Any changes that are required would be made within the php.ini and other configuration files on the web server.
How much control a web site owner has over this information depends on whether they own the server or if the server host is flexible in their customer approach.
It is a good practice to know the limitations of a particular server installation. This screens output is used to find detailed information about how PHP is implemented on the server.
For full details on the information contained within the PHP Info screen visit: http://php.net/phpinfo.
At the top right you will see the toolbar: