Improved detection and reporting of conflicting definitions. Bugs fixed with supercompilation of non-tabular machines, obscure recursive definitions causing compiler crashes, and incorrect processing of divergence for some leaf machines. 2.64 is the first release for over a year Bug fixes for high-level version of interrupt. Time taken for trace-reconstruction massively reduced. Optional file-based pager allows checks to exceed 4GB of storage.
Compaction reduces storage requirements.
Perfomance once physical-memory size is exceeded is improved. The latest manual can be viewed here and is included in the distribution in both HTML and PostScript formats.