On Wed, Sep 16, 2015 at 4:18 PM, Dave G4UGM <dave.g4...@gmail.com> wrote: > It is notable that in order to solve all problems, a computer must permit > self modifying code.
>From a theory of computation view, I don't believe that's true. Any computable function can be computed by a fixed program. For a particular computable function, there may be a more efficient implementation using self-modifying code. On the other hand, computing a particular computable function may require an arbitrariy amount of recursion, so it may take an arbitrarily amount of writable memory. The recusion may, of course, be implemented as some equivalent that doesn't require the computer to have explicit subroutine calls or stack, but the memory may still be required.
