Cron

cron.php is a file that does all the "crunchy" behind-the-scenes work in drupal. Anything that has to be done on a regular basis will be executed when cron is run. These scripts might include:

• Backing up the database
• re-indexing the search database
• clearing/maintaining the cache
• sending messages

You can run it manually by executing cron.php in the root drupal URL. For now cron is set to run automatically several times a day. "Why not run it every hour?" you might ask. Well cron.php takes up a small amount of CPU and RAM on the server each time it is run. If it's run too often the server administrator might complain so a balance must be reached. If you need cron jobs more often than a few times a day you should evaluate your deployment strategy and consider investing in a dedicated server.