Problem with caching

[eluser]Faitas[/eluser]
Hello everybody,

Today, I learning about caching. Yesterday, I learnt file write method.

Problem is in caching in CodeIgniter. I have problems with it. I don't understand about caching in CodeIgniter. Can you help me?

1. How to save cache file (where he saved etc.)
2. How to get all content off web and save it? In PHP is ob_get_content(), how about in CodeIgniter I don't know.
3. Do I need to get libraries, config, helpers or etc?

Thank you so much.