Normal WordPress operation has a cron like functionality that runs scheduled tasks as users visit the blog.

It is possible to replace this with a standalone cron (like UNIX cron).

To disable the “webcron” (i.e. trigerring tasks as URLs are visited) add to your wp-config.php the following:

 define('DISABLE_WP_CRON', true);

Then call this from cron:

 curl http://example.com/wp-cron.php

Optionally you could call wp-cron.php using the php-cli executable.