A basic disk is a disk that is not dynamic
A dynamic disk is a special type of partition only win2k and win XP pro can see. It allows you to do things like combine partitions on different drives to form one drive, and in the process, produce a type of software RAID. There's also a few other features, but thats the main thing. Personaly, every time I tried to use a dynamic disk partiton, somthing went wrong and I had to reload 2k...Thats probably my hardware though.