17 Sep
2015
17 Sep
'15
2:44 p.m.
From: spacewar at gmail.com
On Wed, Sep 16, 2015 at 4:18 PM, Dave G4UGM <dave.g4ugm at gmail.com> wrote:
That may be true for computing but I'm not sure if it is practical
for real time control of complex systems.
Dwight
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.