A capsule tree is a general purpose, self-balancing tree data structure for large, ordered, data-sets. It is designed to provide the same characteristics as B-trees and B+trees, but built from the ground up for in-memory usage. In other words, there are no provisions for “slow” I/O cases.
The original motivation for this tree was a better backend for memory managers.
However, the end result was a new sub-category of trees. The implementation giving here is just one implementation...