Re: How about a Safe Virtual Machine?

Karl Auerbach (
Wed, 5 Oct 1994 18:09:17 +0100

> > But I also believe that building useful Internet services involves
> > significant complexity management, and that complexity management is a
> > particular weakness of Tcl. Sure, the implementation of Safe-Tcl is
> > clean and somewhat simple, but at the cost of complexity of programs
> > built on that platform.
> I think you may have missed a key point that Dave made. We undoubtedly
> want very complex CSCW applications on the network. But the part of
> such systems that has to be executed in a safe language is VERY limited.
> In particular, you only need to use Safe-Tcl for what I call "RPC to
> human beings". Most of your work can go on inside trusted servers on
> the net, programmed in any language you like. The role of Safe-*
> languages is much more limited -- it needs to be able to go off and
> interact with the user on his/her platform, but it needn't contain the
> whole application. I think you overestimate the need for very large
> programs in the safe language. However, I also agree that Tcl needs
> better support for modules.
>In a nutshell ( and maybe not to clearly ! ) this is what I was trying to
>say needed to be broken into "core" functionallity and "mobile" functionallity.
>The core functionallity is always "resident" in the server and can be written
>in language du jour.
>The "mobile" functionallity is interpreted and bound at runtime.
>Lets Identify and list these two basic components.

I agree with all of this with one reservation (which to me is large
and which, to others, will perhaps be small)...

As I guess people are getting tired of hearing, my interest is in
adding means by which users can inject useful, and potentially
long-lived scripts into servers to perform various searching,
aggregation, and "watch for interesting posting" kinds of things.

My feeling is that the programming requirements for this kind of job
will involve more intensive computation (not necessarily in cycles,
but rather, in terms of long-lived and complex data structures) than
are readily supported by a language format in which there is a script
language holding together relatively separate primitive operations.

(How's that for an example of a truely run-on sentence?)