[Axiom-developer] RE: Bootstrapping

[Bill Page]

On November 9, 2005 3:15 PM C Y wrote:

> ... the chicken-egg problem remains.

Why do you keep on insisting that it is a problem? At most it
is a paradox to which we must consider a solution. To me it
seems like you are arguing that chickens should not come from
eggs but rather from some lower life form - maybe grow on
trees? ;) Sorry for my poor attempt at humour ...

> 
> I would like the capability to exist for someday, a thousand
> years from now, someone with only the bare electronics and the
> source code to be able to re-create a running system.

I think the simplest way to achieve this would be through what
is known as a byte-code interpreter: in the source code you
include the machine code for the compiler but not the machine
code for a real machine, but rather for a simpler abstract
machine for which you also provide the complete documentation.
Then the problem becomes first finding a way to simulate that
abstract machine on whatever hardware you have available. Having
done that, you load the provided abstract machine code and
compile your first iteration of the compiler.

The biological analogy seems to remain quite valid. The
abstraction machine code is the chicken's dna. :)

> Symbolics machines were actually very interesting in this
> respect, since IIRC they actually DID implement Lisp at a
> machine level, but they unfortunately didn't survive
> commercially.

Actually all of these machines used microcode to implement
a lisp interpreter. Someone had to write the microcode and
probably used a compiler.

> ...  There are a variety of [lisp] compilers that [are
> bootstrapped] - cmucl and sbcl among them, IIRC, but I think
> there has been some consideration of developing the possibility
> of using clisp, which CAN be bootstrapped with gcc, to build
> cmucl and sbcl.

As you say, writing a lisp compiler in lisp is a very common
strategy. I am sure the Axiom developers where aware of this.

> 
> Basically, I think there is kind of a mantra that the fewer
> bootstrapped software dependencies a system has, the better.

As far as I am concerned that is only because these people
do not understand the issue. Or perhaps it is because they
are concerned with issues - such as security and recovery
that are quite different than building the best language for
a particular job.

> No one denies gcc is such a dependency, but the introduction
> of other such dependencies is not a popular idea, because of
> the reliance of such systems on some available system being
> able to run the original binary. That's an unpopular assumption,
> just on principle.

Stupid principle.

Regards,
Bill Page.