Re: [Caml-list] Kernel in OCAML using native compiler

Re: [Caml-list] Kernel in OCAML using native compiler

[Shannon --jj Behrens]

> Read a good book on Garbage Collection (for instance
> Lins') and you'll
> find out that reference counting is the worst GC
> technique (except for
> some cases of distributed GC). It performs poorly
> and don't handle
> cycles.

Ok, thank you for explaining this to me.

> Ocaml's GC is one of the best and is tunable. It is
> generational,
> copying for the minor collection, and incrementally
> mark&sweep for the
> major collection.

For application development, it is quite nice.

> Even if you did happen to put a refcounting GC
> (which means rewriting
> Ocaml runtime and significant part of the compiler)
> you'll probably
> get worse performance.

In terms of overall time spent doing GC, I'm sure
you're right.  However, I imagine that there are other
algorithms that may provide lower latency (i.e.
shorter pauses caused by GC).  In providing GC for a
kernel, short latency is required, even if the GC will
eventually take twice as much time.

> Generally, using dynamic memory is perhaps not the
> best idea for a
> very low level kernel routine.

Perhaps.  However, I feel that there are some parts of
the kernel that could really benefit from GC.  

In specific, I'd really like to get rid of as many
limits as possible.  For instance, the number of
processes in Minix is fixed (requiring a recompile)
because the process table is not created dynamically. 
If some kernel level malloc were available, the
process table could grow as needed.  I understant that
this is not an "easy" problem.

> You should describe what are you wanting to
> implement in Ocaml inside
> a kernel.

Well, actually, my goal is to write a minimalistic
kernel almost entirely in a high level language like
OCAML.  It appears that many of my goals are the same
as the tunes project you mentioned (which I'm
currently reading through)--especially reflection (as
you mentioned).  

By the way, your first email to me mentioned the GC
issue, and despite three readings, it didn't sink in
until I starting doing those tests.  I apologize that
you had to repeat yourself ;)

Well, I'll keep learning.  Thanks for your patience.

-jj

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Re: [Caml-list] Kernel in OCAML using native compiler

[Shannon --jj Behrens]

I hope you don't mind if I ask you another question
conscerning writing a kernel in OCAML.  I was writing
a few programs to find primes in C and in OCAML so
that I could compare the performance.  It appears that
OCAML offers a very nice compromise of code length and
code execution speed.  However, I also noticed
occasional pauses in the primes generation during
which (I assume) OCAML was doing its (two levels) of
garbage collection.  I fear that reference counting
might be a more appropriate algorithm for *GC in a
kernel* than what I guess is two levels of mark and
sweep. 

Can you comment on this or perhaps offer any
workarounds?  I did play with the Gc module's control
structure, but didn't really gain any huge
improvements.

Thanks for your time,
-jj

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[Caml-list] Kernel in OCAML using native compiler

[Shannon --jj Behrens]

Can anyone point me to any links concerning writing a
kernel in OCAML using the native compiler?  Also,
please feel free to correct me if anyone feels that
this is similar to trying to trisect an angle (i.e.
completely foolish).

Thanks for your patience,
-jj

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Re: [Caml-list] Kernel in OCAML using native compiler

[Florian Hars]

On Thu, Dec 20, 2001 at 01:16:16AM -0800, Shannon --jj Behrens wrote:
> Can anyone point me to any links concerning writing a
> kernel in OCAML using the native compiler?

The last time something like this was discussed, people recommended
http://www.research.att.com/projects/cyclone instead.

Yours, Florian.
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Re: [Caml-list] Kernel in OCAML using native compiler

[Byron Hale]

By the way, a young Asian mathematics teacher claims to have a trisection 
construction for the triangle. So, apparently, it wasn't completely 
foolish, just not so easy.

Regards,

Byron Hale

At 01:16 AM 12/20/2001 -0800, you wrote:
>Can anyone point me to any links concerning writing a
>kernel in OCAML using the native compiler?  Also,
>please feel free to correct me if anyone feels that
>this is similar to trying to trisect an angle (i.e.
>completely foolish).
>
>Thanks for your patience,
>-jj
>
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Re: [Caml-list] Kernel in OCAML using native compiler

[Byron Hale]

Yes, I do recall that. Birkhoff and Mac Lane, among others, discuss it. 
Perhaps he did something a bit different from what I thought. Or, perhaps 
it is a tragedy. The publisher was small and maybe his work was not 
properly reviewed. I just checked and his book title wasn't in my pocket 
computer.

It is also worth remembering that Minsky killed early research into neural 
networks. He proved, correctly, that a (single layer, as it turned out) NN 
could not execute an XOR instruction. His proof turned out to be almost 
irrelevant, because multi-layer NNs can perform XORs.

All sets taken together do not form a set. However, in VGB set theory, they 
do form a class and can be discussed as such. It just seems less nihilistic 
to me.

Thanks for reminding me.

Best,

Byron

At 03:01 PM 12/31/2001 -0800, you wrote:
> > By the way, a young Asian mathematics teacher claims
> > to have a trisection
> > construction for the triangle. So, apparently, it
> > wasn't completely
> > foolish, just not so easy.
>
>I hope you're joking!  Abstract Algebra was used to
>prove that the trisection construction for an angle
>was not impossible.  In the same way that you cannot
>get PI by adding or subtracting two integers, so also
>can you not trisect an angle using the standard
>straight edge and compass.
>
>-jj

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Re: [Caml-list] Kernel in OCAML using native compiler

[Byron Hale]

There was a project at MIT to write a kernel in SML97. I don't have a ready 
link and don't know if it's still extant.

Regards,

Byron Hale

At 01:16 AM 12/20/2001 -0800, you wrote:
>Can anyone point me to any links concerning writing a
>kernel in OCAML using the native compiler?  Also,
>please feel free to correct me if anyone feels that
>this is similar to trying to trisect an angle (i.e.
>completely foolish).
>
>Thanks for your patience,
>-jj
>
>__________________________________________________
>Do You Yahoo!?
>Check out Yahoo! Shopping and Yahoo! Auctions for all of
>your unique holiday gifts! Buy at http://shopping.yahoo.com
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