Stand Alone Erlang

Peter-Henry Mander <>
Fri Mar 12 16:00:18 CET 2004


Hi Dr Joe,

We've tried elinking our Megaco test tool with SAE and found a couple of
issues. The OTP Megaco stack relies on a C link-in driver for parsing,
and I haven't found a way to elink it into the tool. There's also GS
which I feel is a hinderance too.

This has strengthened the argument for implementing future protocol
stacks purely in Erlang. The SIP codec we've written in pure Erlang
using binaries runs at comparable speeds to the Megaco stack, so I
suspect the C driver doesn't confer a huge speed enhancement overall.
Maybe only enough to be noticeble, not orders of magnitude. With
concurrency thrown into the mix, the benefit may be moot.

I've also found that C-nodes (maybe C-drivers too) don't match the
concurrency patterns and ability of Erlang, they're a proverbial pain to
get right! I'm sticking to Erlang for any other protocols we may need to
implement.

The GS problem may coerce future GUIs to use Joe's ex11 too. (-:

/Pete.


On Thu, 11 Mar 2004 11:44:33 +0000
Peter-Henry Mander <> wrote:

> 
> Hi Dr Joe,
> 
> btw, do you get to wear a pincushion instead of a common mortarboard?
> Or do the Swedes leave such excentricities to English? :-)
> 
> Well, the SAE seems to work out of the box without a hitch on R9C-0.
> 
> Were going to give SAE a spin on our own applications. I'll keep you
> posted, including how easy/hard it is to elink in some of the OTP
> libraries like the Megaco stack.
> 
> The teabag version is interesting, the next project doesn't appear to
> rely on OTP much, if at all. Its not a trivial application, it's for a
> SIP protocol load tester. Maybe a good candidate?
> 
> Pete.
> 
> 
> On Thu, 11 Mar 2004 11:35:59 +0100 (CET)
> Joe Armstrong <> wrote:
> 
> > On Thu, 11 Mar 2004, Peter-Henry Mander wrote:
> > 
> > > Hi Prof Joe,
> >      ****       I did't know I was a Prof :-)
> > 
> > > 
> > > What is the state of Stand Alone Erlang? Which is the latest
> > > version of Erlang that can used with SAE? This tool will be ideal
> > > for delivering our testing tool and emulated product for external
> > > use.
> > > 
> > 
> > Good question - I don't know.
> > 
> > It was written for R9X when X < C - and I handed it over to /// -
> > the idea was that it sooner or later would creep into the main
> > distribution. 
> > 
> > It actually gets built in 
> > 
> >     /usr/local/lib/erlang/erts-5.3/bin
> > 
> > But I havn't tested to see if it still works
> > 
> > The windows bit definately does not work.
> > 
> > Try it and see.
> > 
> > The documentation on 
> > 
> >    http://www.sics.se/~joe/sae.html
> > 
> > Should still apply.
> > 
> > Let us know what happens.
> > 
> > As an aside I have made "tea-Bag" Erlang - this is a stripped R9C
> > (ie throw away as much as possible) and just keep just the stuff you
> > need.
> > 
> > I need a minimal system to distribute to a few hundred machines
> > (planet lab) and have made teaBag for this purpose.
> > 
> > If there is any interest I can make it available.
> > 
> > > Pete.




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