Methods and apparatus for debugging software including divisions of an execution history of a debuggee program

In a computing system environment, methods and architecture relate to debugging software programs. The programs, regardless of size, are culled for substantially all memory and register writes (and flow control). An indexing and compression occurs so that upon a later query, and decompression (and display), a user can find and diagnose defects in the software program. To efficiently reconstruct the contents of any memory location or register, backwards tracing of events is comprehensively known for all time, not just select periods. Efficiencies in the indexing function include bunching, replacing actual memory locations with pattern(s) representative of same and dividing an execution history of the software program into manageable sections. Nuances for memory or register effects are also contemplated. Still other embodiments contemplate stand-alone computer program products (on computer-readable media or as a download, or other) or those working in conjunction with other debugging programs.