Subject: Re: Time Limit Functionality
From: "Karsten M. Self" <>
Date: Wed, 20 Jul 2005 21:01:11 -0700
Wed, 20 Jul 2005 21:01:11 -0700
on Thu, Jul 14, 2005 at 01:31:36PM -0600, Anderson, Kelly ( wrote:
> I know that one of the premises of open source is that you are allowed
> to do pretty much anything with the code you want to in terms of fields
> of endeavor. However, I'm wondering if there would be a way to craft a
> license that would simultaneously be open source, but would prevent
> others from implementing a specific feature for a time.

Strictly, this contradicts the OSD, as has been pointed out.  Specifics
may vary, depending on how you're restricting "implementing a specific
feature".  E.g.:  patent restrictionss might be outside the scope of the
copyright license, but might also be seen as socially unacceptable by

This is particularly the case insofar as much software functionality is
highly modualar.  A number of very useful features of my own email
system are wholly independent codebases, which don't rely one code-level
sharing to function.

Practically, this is very similar to what L. Peter Deutsche has done
with Ghostscript, and is sometimes referred to as "delayed public
licensing".  It's  not  a license per se, but simply a label assigned to
the the practice of releasing sofware under one set of licensing
conditions for a period of time, then re-releasing it under an OSI Open
Source / FSF Free Software license.
> For example, suppose you wanted to release an email program as open
> source, but you wanted to prevent (say for two years) anyone from
> implementing a mass mailer using that source code.

You can't.

You *can* release your code under any license of your choosing, however,
then revert that license after some period of time.

If you intend to do this on an ongoing basis, with a developed project
incorporating third-party code, you'd have to get appropriate copyright
assignments to release under your non-free license.  You also would not
be able to incorporate any restricted Free Software licensed code (e.g.:
GPL) in the  non   free  version of your application.
> I know this gets pretty close to item 6. No Discrimination Against
> Fields of Endeavor, but I'm not sure it's exactly the same.

Actually, it's #1 and #3.


Karsten M. Self <>
 What Part of "Gestalt" don't you understand?
   Integrity, we've heard of it:

["application/pgp-signature" not shown]