Linus Torvalds on Android, the Linux fork | Hacker News Reader

Linus Torvalds on Android, the Linux fork

zdnet.com

72 pointshollerith18 comments

While the differences between the Android fork and upstream Linux will introduce pain points during the merge, Linus takes the long view and rightly points out that the Linux project is poised to inherit a huge amount of code that has gone through rigorous real world testing and quite a bit of success.

This is the great thing about the Linux project. If your work doesn't get accepted right away (someone may have objected to the lock model that Android uses, compared to the vanilla Linux lock model), well, just go out in the market and prove that your work is better. Typically with that kind of proof you can start to work on a way forward to integrate your work back in. It's a win-win for the project, since if your endeavor fails they're not stuck with it, but if it takes off they're poised to reap the rewards.

In summary, Forks (that are used for experimental features, not political schisms) are GREAT!

This was hard to understand:

This doesn’t mean that Android isn’t, but it has become something of a Linux fork. That doesn’t, however, as some recent reports had it that Android and Linux are somehow in a fight with each other.

I just gave up and glossed over that part.

The article definitely needs editing. Much of it was painful to read due to omissions, redundancy and generally bad flow.

A comma inserted in "of, a Linux" would help, as would changing both of those commas to '-'. Editing would help most of all.

And this kiddies is why spelling, punctuation and editing matter. If you want to communicate in writing make it easy for your reader.

My best guess: "This doesn't mean that Android isn't [Linux], ..." and "That doesn't [mean], however, ...".

> Google didn’t help matters at all when in the fall of 2010, “Google engineer Patrick Brady stated unambiguously that Android is not Linux” That was never true.

Another example why naming popular desktop OSes as "GNU/Linux" (as opposed to plain "Linux") is important, unless all parties know the context. And never compare "Android" and "Linux", unless the "Android" comes right before the word "kernel".

Summary: Linus asserts that Android, the fastest growing smartphone platform, comes from Linux and will return to Linux.

The key to understanding this is to change the "s" in Linus' name to an "x" and see what happens.

> Fortunately, thanks to the GPLv2, all the significant changes come back to the mainstream kernel.

How exactly, does that work ?

This is a valid questions, because iirc, as long as these companies don't distribute their linux fork outside of their company, they do not need to release the source. GPL takes effect when you distribute binaries, not when you create them.

If you copy or distribute the derivate work in either object code or executable form, you are obliged to make the source available.

Arguably anyone who has a phone, has had a copy in executable form distributed to them, and can ask for the source.

He was talking about Google's private fork of Linux for their servers to run Google search.

He was talking about companies in general tweaking linux for their particular uses.

Indeed, if you focus on the preceding bit about Google's in-house linux for their own servers, then there would be no distribution and arguably GPL2 could not force those modifications to be made public.

But I would imagine that he's probably quite versed in GPL2 and knows this -- so since he brought it up specifically, it suggests he was probably thinking at that point more about cases where distribution does happen (e.g. Android, embedded etc).

Perhaps he considers it a 'significant change' primarily if there's some sort of distribution ;)

Exactly. I guess the license doesn't really matter a lot in this case, as long as it's some sort of Open Source license. The benefit the companies have by getting their patches merged back in is that they don't necessarily have to maintain the patches themselves anymore. The GPL, however, should not have any effect on that, as long as the work is used internally only.

It used to be the case that licenses required you to submit your modifications back to the source. Lucent's first stab at opening Plan 9 From Bell Labs back in '99 had such a clause.

Derivative works of the kernel must also be licensed under the GPL, meaning their source code must be available. So, if the Linux developers like the changes someone else has made, they can merge them in.

No. GPL doesn't mean that derivative works source needs to be available. Thus Google may very well have modifications which are never made public.

The source must be available to those who have access to the program. If Google ever distributed those modifications, they would have to distribute the source as well.

That's the big if. Especially when the paragraph was discussing Googles performance tweaks to their in-house kernel used in their servers.

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