BSD and MIT license "compliance" with the MS-PL

Matthew Flaschen matthew.flaschen at
Sat Apr 18 06:41:44 UTC 2009

Donovan Hawkins wrote:
> As for copyleft, I'll use as the definition that "copyleft is a tool
> to ensure permissions are maintained during distribution," as opposed
> to copyright which is a tool to ensure that restrictions are
> maintained during distribution. It's simple, fits the reason the word
> was chosen, and matches the FSF's own description of the principles
> fairly well.

I would agree that's an equivalent formulation.

> Weak copyleft is perhaps harder to define, but it generally draws
> some sort of distinction between modifying the original code and
> using the code in a larger project. It certainly can't mean only
> ensuring permissions for some of the people who use the same piece of
>  software...that isn't weak copyleft, it's broken copyleft.

I agree.  Weak copyleft means all of the people, but only part of the
derivative code.

> Still, it does pass the license proliferation test: it is unique in
> combining the most restrictive license terms available for open
> source with the most permissive license terms available for closed source.

Agreed.  You certainly can't fault the creativity (there are other words
for it) of MS's legal team.

Matt Flaschen

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