Starting Erlang

Joe Armstrong <>
Thu Apr 25 09:42:50 CEST 2002


> Joe Armstrong <> wrote:
> 
> >     I am now turning my attention to the Erlang start sequence itself.
> > 
> >         Questions:
> > 
> > 	Does *anybody* understand (I mean *really* understand the
> > Erlang start-boot sequence).
> 
> Yes, I'd like to think that I do (and I think that e.g. magnus does).

  This was more of a rhetorical question - it is (as you say) reasonably
simple :-)

  What I was wondering more was if all the things that we made provision for
in the boot sequence are actually used.

  The vast majority of systems seem to fetch their code from a file system
either local, NFS mounted or flashed.

  init.erl has the possibility to fetch code from the net.

  *does anybody use the -loader inet -hosts ...* stuff ?????


> 
> > Is all this junk in the .script files
> > really necessary.
> 
> Well... of course this is just one solution to the problem, there are
> others.
> 
> > 	Do you think there would be any objections if I reworked it all?
> 
> Please make sure that you understand *everything* about how
> script/boot files are used before changing this (I got the impression
> from your question that you don't).  It's very easy to fall into the
> old trap "I don't understand this code, it looks complicated, it can't
> be necessary, I'll remove it".
> 
> Also, I don't think it's very complicated.  init.erl interprets the
> boot script (which usually is generated by a tool like systools.erl)
> A boot script for a complete product may look complicated, but
> remember start_old.script?  It was pretty small.

  Actually, one small addition to the init scripting language would
solve a lot of problems (i.e. a change to init:eval_script), 
i.e. add a:

	{loadCode, Mod, Bin}

  Instruction - this way you could include code directly in the boot file.
A simple change to systools could ensure that the correct code is found and
added.


    /Joe
> 




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