Jolt's 'black box' images let you debug a crashed program by loading its full state
Program images and portable Scheme back ends for Jolt
Jolt, a Clojure implementation on Chez Scheme, now supports program images in the style of Common Lisp and Smalltalk, allowing developers to dump the entire program state on error and restore it later for post-mortem debugging. The project also decoupled its Scheme layer from Chez, enabling a portable runtime that can target Gambit and run in the browser via Gambit's JavaScript backend. This opens up an ecosystem of Scheme implementations, each with different trade-offs, while keeping the same Clojure codebase.
You can think of the program image as a black box recorder. Just like an aircraft stores the instrument states to allow investigators to decide afterwards what to look at, a program image gives you all the information needed to debug the problem.