Re: kernel stack challenge

From: Horst von Brand
Date: Tue Apr 06 2004 - 21:27:32 EST


Sergiy Lozovsky <serge_lozovsky@xxxxxxxxx> said:

[...]

> I didn't just pick up LISP - I EXPLAINED my reasons.
> if you missed my explanation here is a short summary.
>
> 1. I needed solution to implement some procedural
> functionality within the kernel.

Fair enough, if really needed.

> This functionality
> should be expressed with some high level language
> (shorter development time and more compact source
> code).

That it is _expressed_ in a sky-high-level-language has nothing at all to
do with _implementing_ said language (fully?) inside the kernel. Heck, the
kernel has no built-in C compiler + development environment + runtime
either!

> This functionality should be
> loadable/unloadable to the kernel.

A compact, easy to interpret blob pushed into the kernel, a module hooking
into the "right places", ...

> 2. Size of the interpreter should be minimal.

Zero is just about right for me.

> 3. Kind of real time - no ordinary garbage collector.
> And automatic memory management at the same time.

Oxymoron.

> 4. Easiest syntax possible - so interpreter would be
> compact. Simpler - the better :-) I don't like
> complicated things :-)

Why do you need the interpreter in kernel? If you do need it, why does it
have to be a general-purpose language, and not an "interpreter" for a
stylized data structure, carefully designed for the task?

> 5. Well known. So there would be people around who
> already know this language and expectations are clear.
> And there are books around about this language.

C is fine in that sense. Even much better than LISP. Specially among the
sysadmin/kernel hacker/general Unix geek crowd...

> 6. Ability to handle/represent complex data
> structures.

C qualifies.

> 7. Errors/bugs in loadable functions should not cause
> trouble for other tasks and kernel itself. (To the
> extent possible for sure).

Hard to do in any case. Just be careful...

> 8. It should be universal (general purpose) language
> which gives ability to make any manipulations with
> numbers, strings, bits and data structures. So I would
> be sure that functionality I want to express is not
> limited by the language.

But _why_?
--
Dr. Horst H. von Brand User #22616 counter.li.org
Departamento de Informatica Fono: +56 32 654431
Universidad Tecnica Federico Santa Maria +56 32 654239
Casilla 110-V, Valparaiso, Chile Fax: +56 32 797513
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