RAID question, maybe

This may be a stupid question, but what the heck. I have seen systems with more than 4 hard drives. How is this possible with only 2 IDE interfaces. Do you have to add controller cards? Also when you buy a motherboard with RAID support does it automatically come with more than 2 IDE interfaces? The reason I ask is that I believe I have seen motherbaords that support RAID, but have only the 2 standard IDE interfaces?

most IDE RAID motherboards have 4 IDE channels, newer motherboards are coming with SATA RAID and they have 2 or 4 SATA channels for RAID and 2 IDE channels that cannot be used with RAID