Erlang vs Linux

Joe Armstrong <>
Thu Feb 27 14:19:49 CET 2003

On Wed, 26 Feb 2003, Miguel Barreiro Paz wrote:

> 	Just out of curiosity, I've coincidentally found that patent
> EP0544637 (equivalent to WO9311484, for those out of the EU) effectively
> patents Erlang and OTP. 

  No it  doesn't -  The patent  covers the combination  of Erlang  + A
particular  application   +  A  particular  way   of  programming  the

  The language was Erlang as is was in 1993 which is very different to
today (this  was before  Funs, binaries, bit  syntax, etc.)   had been
added to  the language so  it refers to  a *different* version  of the

  The particular application was a  PABX programmed with the so called
"half call model"

  The architecture was the so-called AOS (Application OS) this
was *before* BOS (basic OS) which was *before* OTP.

  In no way  can todays Erlang/OTP be considered  as a minor variation
of the Erlang/AOS referred to in  the patent - there are several major
an nonobvious additions since the work in 1993.

  <aside> to  be in violation of  a patent you must  violate *all* the
clauses  of the  patent -  so  for a  Non PABX  application you  could
*never* be in violation of the patent </aside>

  In any case even if the patent referred was applicable to the current
Erlang/OTP (which it is not) then 2.1b of the license would apply

--- quote
2. Source Code License.

2.1. The Initial Developer Grant.
The Initial Developer hereby grants You a world-wide, royalty-free,
non-exclusive license, subject to third party intellectual property

(a) to use, reproduce, modify, display, perform, sublicense and
    distribute the Original Code (or portions thereof) with or without
    Modifications, or as part of a Larger Work; and 

(b) under patents now or hereafter owned or controlled by Initial
    Developer, to make, have made, use and sell (``Utilize'') the
    Original Code (or portions thereof), but solely to the extent that
    any such patent is reasonably necessary to enable You to Utilize
    the Original Code (or portions thereof) and not to any greater
    extent that may be necessary to Utilize further Modifications or

--- end
  The  initial  developer was  Ericsson.   2.1(b)  says  that you  can
"Utilize" the system even if  such utilisation is regulated by patents
"now or hereafter owned or controlled by Initial Developer".

  Since Ericsson wants  you to use Erlang (That's  why it was released
as Open  Source) - they  explicitly granted you  the right to  use the
system  - even  if the  use of  the system  was covered  by  their own

  If a  competitor to  Ericsson (say Nortel)  held such a  patent then
their might have been a problem.



  1) The patent  refers to a historical vsn  of Erlang + AOS  + A PABX
application written in a particular  manner. This is very different to
todays' Erlang + OTP. 

  2) Ericsson granted you  the right to use OTP even  when such use is
governed by patents held by Ericsson.


> I understand that its purpose is to guard
> Ericsson's shoulders, but the legal status of an opensourced system that
> is at the same time covered by a patent is a bit questionable without
> an explicit statement by the patent holder.

2.1(b) was an explicit statement

> 	Can anyone comment on this?
> Regards,
> Miguel

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