ipod

This website seems pretty good for information on ipods.
It works similarly to a CD but it compresses files to store more information, thats it but I think this information is key so we can put different thing for CD and ipod, the others are different enough anyway. The link is:

www.tech-faq.com/how-does-an-ipod-work.shtml

I just have to say that HowStuffWorks is actually rubbish for information!