The HighPoint 370 chip. It's a chip which connects to a virtual PCI channel to provide two ATA100 channels and basic RAID capabilities. It requires a device driver, but is more robust than the software-only RAID solutions, such as the FastTrack controllers.
This chip (or the HPT370a) is found on the Abit motherboards with a -RAID ending, such as the ABit KT7-RAID and the ABit KG7-RAID.
There are newer, more feature laden versions such as the HPT371. HighPoint's website tells more.