Undo.ai has created a proprietary highly-optimised JIT translation engine that can record the execution of a program completely, perfectly, and efficiently. The resulting recording can be analysed to extract any detail of the program’s execution: every line of code that executed and every memory location at any point in its execution history. This is done in a very efficient manner, such that only non-deterministic stimuli are captured, and re-execution is used to compute preceding states.