> Doesn't AS/400 use an IR approach as well? Which let IBM seamlessly migrate the underlying CPU a few(?) times now? In these systems both something like IR an

> Doesn't AS/400 use an IR approach as well? Which let IBM seamlessly migrate the underlying CPU a few(?) times now? In these systems both something like IR and final assembly is stored in the binary. The OS recompiles the IR for the current CPU if necessary and replaces the assembly in the binary. That way there is no compilation overhead unless architectures are changed.