What is a RAID Controller and How do you use it?

I got this raid controller card off someone, that looks exactly like the following http://inferno.slug.org/jpeg/7506-8.jpg





First of all, what is RAID Controller. Is it simply in the above case an IDE expansion slot? Can I plug in regular IDE hard-drives into these IDE-looking slots?What is a RAID Controller and How do you use it?
A Raid controller is a controller for a ';redundant array of inexpensive disks';. You can do a few neat things with them, for example, you can a) expand the capacity of the drives beyond what a single drive can do or b) mirror data and prevent data loss while preserving the integrity of that data.





There is a wealth of information on wikipedia on this topic.





There are hardware and software raid systems. Chances are, you are posting this question because your motherboard has a RAID controller. If this is the case, you don't need to do anything to have it except set some conditions in the bios to activate it. You must have at least two hard drives for this to work. Investigate the hardware manuals to learn more.





http://en.wikipedia.org/wiki/RAID