Erlang/OTP and SDL

Inswitch Solutions - Erlang Evaluation <>
Wed Sep 15 16:30:05 CEST 2004


Hi Matthias,

In your last mail you wrote:
>MTP-2 is defined in about 50 pages of SDL....
>..... The Erlang code was hopelessly
>slow, but that was OK: the goal was to build a reference
>implementation to test the real (hardware-accelerated) implementation
>against.

Why was Erlang code for MTP2 slow? Would you recommend developing higher
layers (MTP3 or ISUP) in Erlang?


thanks,
Eduardo Figoli
INSwitch Solutions


----- Original Message -----
From: "Matthias Lang" <>
To: "Ulf Wiger (AL/EAB)" <>
Cc: <>
Sent: Wednesday, September 15, 2004 11:07 AM
Subject: RE: Erlang/OTP and SDL


>
>
>  Eranga> How good is the SDL support in Erlang? Are there any tools
>  Eranga> that can generate Erlang code from a SDL spec?
>
>  Ulf> In general, one can say that it's entirely straightforward
>  Ulf> to generate Erlang from SDL
>
> Just as an example: MTP-2 is defined in about 50 pages of SDL
> diagrams. Without knowing anything about MTP-2, I "brainlessly"
> translated it into Erlang. By "brainlessly", I mean I used a process
> whenever SDL had a process, sent a message whenever SDL sent a message
> and sat in receive whenever SDL wanted me to wait for a message.
>
> The result was just over 2000 lines of Erlang code. While doing that,
> I found two bugs in the SDL in the MTP-2 standard, both of which have
> been corrected in a later version. The Erlang code was hopelessly
> slow, but that was OK: the goal was to build a reference
> implementation to test the real (hardware-accelerated) implementation
> against.
>
> I didn't use any tools.
>
> Matthias




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