System

About

The System module is integral to the site, and provides basic but extensible functionality for use by other modules and themes. Some integral elements of Drupal are contained in and managed by the System module, including caching, enabling and disabling modules and themes, preparing and displaying the administrative page, and configuring fundamental site settings. A number of key system maintenance operations are also part of the System module. For more information, see the online handbook entry for System module.

Uses

Managing modules
The System module allows users with the appropriate permissions to enable and disable modules on the Modules administration page. Drupal comes with a number of core modules, and each module provides a discrete set of features and may be enabled or disabled depending on the needs of the site. Many additional modules contributed by members of the Drupal community are available for download at the Drupal.org module page.
Managing themes
The System module allows users with the appropriate permissions to enable and disable themes on the Appearance administration page. Themes determine the design and presentation of your site. Drupal comes packaged with several core themes, and additional contributed themes are available at the Drupal.org theme page.
Managing caching
The System module allows users with the appropriate permissions to manage caching on the Performance settings page. Drupal has a robust caching system that allows the efficient re-use of previously-constructed web pages and web page components. Pages requested by anonymous users are stored in a compressed format; depending on your site configuration and the amount of your web traffic tied to anonymous visitors, the caching system may significantly increase the speed of your site.
Performing system maintenance
In order for the site and its modules to continue to operate well, a set of routine administrative operations must run on a regular basis. The System module manages this task by making use of a system cron job. You can verify the status of cron tasks by visiting the Status report page. For more information, see the online handbook entry for configuring cron jobs. You can set up cron job by visiting Cron configuration page
Configuring basic site settings
The System module also handles basic configuration options for your site, including Date and time settings, File system settings, Clean URL support, Site name and other information, and a Maintenance mode for taking your site temporarily offline.
Configuring actions
Actions are individual tasks that the system can do, such as unpublishing a piece of content or banning a user. Modules, such as the Trigger module, can fire these actions when certain system events happen; for example, when a new post is added or when a user logs in. Modules may also provide additional actions. Visit the Actions page to configure actions.