Linked by Thom Holwerda on Thu 23rd Jul 2009 09:43 UTC
Microsoft Sometimes, some things are just too good to be true. Earlier this week, Microsoft made a relatively stunning announcement that it would contribute some 20000 lines of code to the Linux kernel, licensed under the GPL. Microsoft isn't particularly fond of either Linux or the GPL, so this was pretty big news. As it turns out, the code drop was brought on by... A GPL violation.
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RE[5]: Didn't require release
by Ford Prefect on Thu 23rd Jul 2009 19:49 UTC in reply to "RE[4]: Didn't require release"
Ford Prefect
Member since:
2006-01-16

Apparently you did not read my post thoroughly. They did own 100% of the code. However, as soon as they link it to the kernel, it is "derived work" of the kernel. There is where they loose the right to dual-license: They are not allowed to link Non-GPL licensed code to the kernel.

That is, effectively, what they call the 'viral' effect. I don't mean it negatively. I use GPL for my software myself.

Reply Parent Score: 2

RE[6]: Didn't require release
by eraz0r on Thu 23rd Jul 2009 22:12 in reply to "RE[5]: Didn't require release"
eraz0r Member since:
2007-03-25

Apparently you did not read my post thoroughly. They did own 100% of the code. However, as soon as they link it to the kernel, it is "derived work" of the kernel. There is where they loose the right to dual-license: They are not allowed to link Non-GPL licensed code to the kernel.


You're not exactly right here. They are allowed to license their code under whatever license they like as long as it is ALSO licensed under the GPL. GPL never prevented putting the code under many licenses. In fact, nobody can prevent a legitimate copyright holder from applying any license on the code as long as the license does not violate the law.

Reply Parent Score: 2

Ford Prefect Member since:
2006-01-16

Ok I try to make it clear again:
If you link your code to GPL code and distribute it, it is considered derived work and has also to be distributed under GPL.

They can surely distribute their code under whatever license they want but not if linking to the linux kernel.

And this is a perfectly o.k. feature of the GPL, which some call "viral". And I am lucky the GPL is as it is.

Reply Parent Score: 2

RE[6]: Didn't require release
by lemur2 on Thu 23rd Jul 2009 23:31 in reply to "RE[5]: Didn't require release"
lemur2 Member since:
2007-02-17

Apparently you did not read my post thoroughly. They did own 100% of the code. However, as soon as they link it to the kernel, it is "derived work" of the kernel. There is where they loose the right to dual-license: They are not allowed to link Non-GPL licensed code to the kernel. That is, effectively, what they call the 'viral' effect. I don't mean it negatively. I use GPL for my software myself.


They might call it viral, but that is just an attempt to smear. The GPL is not viral ... Microsoft's HyperV product was being distributed with parts of it's code being GPL code.

Microsoft did that. It was Microsoft who mixed the GPL code and their own code together in the one product.

So Microsoft had some choices ... either excise the GPL code from HyperV and replace it with their own code to perform the same function, or make the entire HyperV product GPL, or drop the whole thing and not distribute it.

They chose to make the whole HyperV product GPL. Microsoft's choice. No doubt, this choice was made because it was the least effort for Microsoft.

That observation in turn leads us to the conclusion that the MAJORITY of the HyperV product must have been GPL code, otherwise it would have been easier for Microsoft to just re-write and replace the GPL bits.

That observation in turn leads to the further observation that the GPL wasn't viral at all in the HyperV product, but rather that Microsoft had tried to close GPL code by adding a bit of their own to it, and had not managed to get away with it.

Edited 2009-07-23 23:35 UTC

Reply Parent Score: 1

RE[7]: Didn't require release
by microsys on Fri 24th Jul 2009 07:36 in reply to "RE[6]: Didn't require release"
microsys Member since:
2009-07-23

The driver for generating a better interface for the kernel to the HyperV(M) has GPL in the source, so they GLPed only the driver. Not the whole HyperV...

Reply Parent Score: 1

TemporalBeing Member since:
2007-08-22

Apparently you did not read my post thoroughly. They did own 100% of the code. However, as soon as they link it to the kernel, it is "derived work" of the kernel. There is where they loose the right to dual-license: They are not allowed to link Non-GPL licensed code to the kernel.

That is, effectively, what they call the 'viral' effect. I don't mean it negatively. I use GPL for my software myself.


The GPL does prevent you from licensing other people's code under a different license. However, it does not prevent you from licensing your own code with more than one license.

That is - you can take a GPL produce, add an extension to it, and the extension itself be dual licensed so long as no one else's GPL code is dual licensed.

Thus, the GPL is NOT viral.

So Microsoft and anyone else CAN dual license the source they are putting into the Linux Kernel if they like - it has to have the GPL to be compatible with the Linux Kernel, and any code that only they own - code that is not tainted by any GPL code they do not own - can be dual licensed.

It is to their advantage to dual license? Not necessarily, but the GPL does give them that freedom to do so. The key is ownership, and proving that what you are dual licensing is not under a single license from someone else - that you own it all and have the ability to do that.

If the GPL forbid dual licensing in that nature, then all dual licensing with the GPL would be forbidden, and we know that is not the case.

Reply Parent Score: 2