Re: How about a Safe Virtual Machine?

Guido.van.Rossum@cwi.nl
Sun, 02 Oct 1994 10:16:29 +0100

> Has anyone looked at the virtual machine that GNU is planning toi use
> for the C interpreter? I hear it can already run programs compiled
> by GNU C et al.
>
> I quite like forth, but has anyone done any work compiling
> things like C into it? It is possible, I'm sure, but
> I wonder if it works well.

Hm... I think the whole idea of a "safe virtual machine" won't work.
As Nathaniel points out, the operations that need to be verified or
confirmed (etc.) are usually at a much higher level of abstraction.
When thinking (as a result of this discussion) about making Python
safe, maybe 95% of the unsafe operations are library functions -- 4%
are high-level operations that negotiate access to the library
(e.g. importing modules); only a tiny fraction of unsafe operations
are close to the level of the Python virtual machine (such as object
attributes that provide read-write access to internals of the
interpreter).

--Guido van Rossum, CWI, Amsterdam <mailto:Guido.van.Rossum@cwi.nl>
<http://www.cwi.nl/cwi/people/Guido.van.Rossum.html>