LispOS directly on hardware or on Unix kernel?

Reginald S. Perry
Tue, 29 Apr 1997 13:35:22 -0700

>"Martin" == Martin Cracauer <> writes:

> But I think your goal to set Lisp on top of the hardware is out of
> question.

Yeah. :-)

After listening to the various arguments, I agree that we dont want to
do all of that stuff. I would say that care still has to be taken. We
need to choose what to build on carefully. It seems to me that the C
runtime is built into Unix. I would like to see Lisp runtime support
in the OS not built on top of it. That would give us optimal
interaction with the VM.

> Leaving the GUI problem out, I think it is definitvly better to
> start with a kernel we have source for (like FreeBSD or Linux) and
> add replacements for those parts we don't like. You could do your
> own messaging stuff instead of Unix signals. The FreeBSD VM is quite
> programmable, Lisp-specific features (i.e. GC only of pages-in
> pages) could be done quite easily.

> I already talked to John Dyson, who implemented the FreeBSD virtual
> memory system and he was quite interestedt to work with the "List
> processing" guys to make "his" system the best quice.

> Talking of John's implementation, I would like to use a kernel like
> FreeBSD's also for the reason of performance and matureness,
> too. The FreeBSD VM several times faster than the NetBSD one, for
> example. Just define a workload that causes a lot of paging and run
> it on both OSes.

I just installed FreeBSD 2.2.1 and I have been very impressed with the
VM. Loads that sweat FreeBSD 2.1.x and used to sweat my Linux 1.1.x
system and sweat my Digital Unix system work great in 2.2.1. Of course
you have to give it more swap than you would normally think, but once
I did that, its pretty darn impressive.

> I'd say we can't do that well without investing as much time as John
> did. John is one of the most respected VM hackers and it took hom
> years of his free-software time to implement this. Not to speak of
> all the problems that have been seen and fixed with all free OSes.

> I don't know what you are used to in the Unix world, but I think you
> would be surprised how badly most of the key FreeBSD folks try to
> get things right. They didn't invent the idea of ASCII streams to
> couple commandline tools and they shoot a Posix spec to the moon on
> each first sunday of a quarter. But what they do, what and how they
> modify and reimplement in their system, is usually the best solution
> for the problem at hand and not "worse-is-better".

> They are C programmer (OK, most, one Modula-3 guy who implemented an
> important Network service) and they won't change their system to be
> LispOS.

> But you can tak to them about what you think is right and even if it
> doesn't fit their needs (what is likely given the differences in
> language, runtime model, used tools), they usually get the idea what
> the hell you are talking about. Most likely they are willing to give
> your the assitance you need to make your own additions working on
> FreeBSD and keep your sources in a way that future work FreeBSD
> doesn't break it.

That might be a good idea. I would think though that this would set
off another big argument about Linux vs. FreeBSD. What I would say is
do it on both. That way no one has to give up their favorite OS. I
just got my home system to the point where it runs like a champ (for a
486/66), and I am loathe to change it. 


Reginald S. Perry                      e-mail:   
Digital Equipment Corporation
Performance Manager Group	      

My opinions are barely my own. Clearly Digital wants nothing to do with them