B.11 Changes from 2.28 to 2.64

• Further bug fixes to interrupt operator.

• New paging system allowing problems beyond 4G using disk-based storage, with user-controlled compaction.

• Performance improved when collecting counter-examples (the delay between a trace being reported and debugging becoming available.)

• subtype definitions documented.

• New -depth flag added to batch mode.

• Uses later releases of Tcl/Tk and gcc (the later with improved code generation.)

• Refinement algorithm restructured to reduce overheads in the common case of checking super-compiled machines.