This paper compares the performance of B-trees and hash trees (H-trees) to implement-keyed files for direct access by key and sequential access. Hash trees are partially defined in this paper; for a culler definition readers are referred to earlier papers by the authors. For sequential access, H-trees are superior to B-trees (although not to B⁺-trees). For direct access, H-trees require 1.10 probes per average access and so are superior to general B-trees. H-trees are also superior for insertions and deletions.