[SharpOS Developers] Licensing

[Scott B. <sb...@me...>]

So much for attending either meeting. Weekend schedules have that way of 
changing on a dime...

As I was talking with William last week (I like using real names rather 
than IRC nicks. You get to know people faster that way), I would 
advocate a dual license between LGPL (maybe GPL v2, but I'll get that in 
a moment) and a commercial license. This gives us the best flexibility 
for potential commercial options down the road, while maintaining the 
openness that the project wants.

I would say LGPL over GPL because of the intended modularity that we 
*will* have in the system. For the sake of avoiding confusion, I refer 
to the "kernel" as the whole system (JIT compiler, VFS, scheduler, 
memory, everything, including the other system-level microkernel 
servers). By using LGPL for the whole kernel and system, rather than 
just the CLR userspace libraries (the BCL from the CLR spec, corlib, 
etc), this allows us to develop "premium" kernel modules that may be 
under a different license, or even closed-source. For example, to stem 
off another discussion, we could have a standard GC in the open version 
of the system, but sell a high-performance or embedded device / low 
memory GC module that is closed source. This wouldn't be possible if the 
kernel was purely GPL.

Further, using LGPL will alleviate grumbling on the part of device 
manufacturers writing their own closed drivers. We must accept the 
reality that they will want to keep their drivers closed-source. Even 
though this doesn't mean much in the CLR bytecode world, where someone 
could rather easily reverse-engineer the bytecode. But like Apple DRM, 
with a nod and a wink more or less, it's the thought and flexibility 
that counts.

Now, for purely commercial interests, like MySQL and others, we can dual 
license under a commercial license for those companies who don't want 
LGPL at all. This would make most sense in the case of an embedded 
device manufacturer who wants to embed a customized version of SharpOS 
(some futuristic cable set top box / home media server comes to mind). 
Or we could require commercial licensing for general computer 
manufacturers who want to load and brand SharpOS on their systems (e.g. 
Dell).

The big requirement for doing this dual-licensing is that anyone who 
contributes to SharpOS must have on file some type of copyright 
assignment. MySQL, Trolltech, and others require this, because of their 
commercial licensing. If people don't want to sign the assignment, then 
we would have to maintain another fork of the OS. Then someone would 
have to go back and clean-room reimplement that open code in the 
commercial branch.

I'd be happy to write up a sample assignment paper, as I'm used to it. 
But it's important that we get such a large decision out of the way now, 
before we get a huge number of commiters.

Finally, don't quote me on this because I'm not a lawyer (duh), but 
remember that copyrights only cover the specific implementation, not the 
idea. Thus, and while I'm not directly recommending we do this, you can 
look at Linux, BSD, etc code, get the *idea* of what it does (especially 
drivers for hard-to-document devices), and then write our own code. We 
just can't directly copy and paste. And in reality, we couldn't copy and 
paste anyway, since we're using a completely different language / 
environment.

Okay, long email number one down... :D I'll let everyone discuss this 
before I go on to write the next one.