@amoroso @sgharms "In the old days" - Interlisp-D was Lisp all the way down, until you got to the microcode implementation of the Lisp instruction set. All features of an OS were present - file system, drivers for the hardware like disks, network stack, process management, everything -- was all running, debuggable, changeable in the same space as any other Lisp functions you wrote. "Teleraid" was like remote GDB - reach in and look at/modify a crashed machine, etc.