B-Trees are balanced, like RB trees.
They have a large number of children (large branching factor), unlike RB trees.
The branching factor is determined by the size of disk transfers (page size).
Each object (node) referenced requires a DiskRead.
Each object modified requires a DiskWrite.
The root of the tree is kept in memory at all times.
Insert, Delete, Search = O(h), where h is the height of the tree.
O(lgn), though much less in reality (