LinuxQuestions.org - understanding anacron (with/without cron)

Hello,

I am having a hard time understanding exactly how anacron works. I can read the configuration files for both cron and anacron, and I've already configured cron. As I use a normal computer, I need anacron to do my backups, because, of course, I shut it down and I can't ensure that the computer is turned on exactly at the right time.

I've configured cron through crontab -e command, but of course I know that I can also place some scripts in /etc/cron.d/ that can be run regularly.

What I don't understand though, is how anacron refers to the SAME job that I scheduled with cron. Moreover, can anacron be used without cron, so that it runs a daily job? (and of course, so that it runs after it boots up, etc.)

For instance, after I configure in crontab a command, how could anacron take over that particular job? I hope I've been clear enough. I've searched on the internet quite a bit, and even though everybody explained very well how one can configure both cron and anacron, I still haven't been able to understand how to implement anacron in relation to (or independently of) cron.

Thanks