Linus Torvalds on Android, the Linux fork

Linus Torvalds on Android, the Linux fork

Summary: There's still a lot of distance between Google's Android and its parent operating system Linux, but eventually, the gap will close... eventually.


Vancouver, British Columbia—During his question and answer session at the Linux Foundation's LinuxCon, Linus Torvalds, founder of Linux, revealed that while mainstream Linux and its popular smartphone and tablet son Google's Android still aren't as close as they should be, they're slowly—ever so slowly—coming back together.

Over the last several years, some people have been seeing Android as not being Linux at all. 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. Android has always been Linux.

What's also true though is that Google took Android in its own direction, a direction that wasn't compatible with the mainstream Linux kernel. As Greg Kroah-Hartman, head of the Linux Driver Project and a Novell engineer, wrote in Android and the Linux kernel community, "The Android kernel code is more than just the few weird drivers that were in the drivers/staging/androidsubdirectory in the kernel. In order to get a working Android system, you need the new lock type they have created, as well as hooks in the core system for their security model. In order to write a driver for hardware to work on Android, you need to properly integrate into this new lock, as well as sometimes the bizarre security model. Oh, and then there's the totally-different framebuffer driver infrastructure as well." As you might imagine, that hasn't gone over well in Android circles.

This disagreement sprang from several sources. One was that Google's Android developers had taken their own way to address power issues with WakeLocks. The other cause, as Google open source engineering manager Chris DiBona essentially said, was that Android's programmers were so busy working on Android device specifics that they had done a poor job of co-coordinating with the Linux kernel developers.

The upshot was that developer circles have had a lot of heated words over what's the right way of handling Android specific code in Linux. Linus Torvalds dropped the Android drivers from the main Linux kernel in late 2009. 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. Or, even, as one claim had it in March 2011, that Android was somehow in danger of being sued by Linux because of  Gnu General Public License, version 2 (GPLv2) violations. As Linus himself said at the time, claims that the Android violated the GPL were “totally bogus. We’ve always made it very clear that the kernel system call interfaces do not in any way result in a derived work as per the GPL, and the kernel details are exported through the kernel headers to all the normal glibc interfaces too.”

Still, it seemed as if Android and Linux were moving more on parallel paths than together, and that is indeed the case. At LinuxCon, Torvalds explained, that “there's still a lot of merger to be done. ... but that eventually Android and Linux would come back to a common kernel, but it will probably not be for four to five years.”

Kroah-Hartman added that one problem is that "Google's Android team is very small and over-subscribed to so they're resource restrained It would be cheaper in the long run for them to work with us." Torvalds added that "I'm not at all afraid of forks... even when forks happen there are all these points of pain where two groups have had different issues, it just takes a while for people to join back, but the joining will happen. We're just going different directions for a while, but in the long run the sides will come together so I'm not worried."

Kroah-Hartman,pointed out that for years Google's in-house Linux that it uses for servers, was a fork of the Linux 2.4 for many years. Torvalds explained that Google did this because they had made so many performance tweaks to improve it for Google's search engine. He also added that many other companies tweak Linux for their particular uses. Fortunately, thanks to the GPLv2, all the significant changes come back to the mainstream kernel.

So, for the next few years, Android, while still a Linux, is indeed a Linux fork. In the long run, though, Torvalds is sure that Android will return to the mainstream Linux kernel. For better or worse though that may not be until 2016. Fortunately, for all end-users and almost all Android developers none of this will make any real world difference.

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Topics: Android, Smartphones, Security, Operating Systems, Open Source, Mobility, Mobile OS, Linux, Hardware, Google, Software

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  • Fortunately, thanks to the GPLv2, all the significant changes come back to

    No they don't. Google hasn't released their version of Linux to the outside world, have they?

    PS: Since honeycomb wasn't completely open sourced, maybe they're still violating GPL2 (I'm no expert on these things, but I've read compelling arguments for that)
    • RE: Linus Torvalds on Android, the Linux fork

      No they aren't.

      All of the user space software may be proprietary, but the kernel is public and available.

      Much, though not all, of the user space code is available.
  • You seem to be tip-toeing around the Google - Motorola deal

    Steven, what's your opinion on the Motorola deal? Does this strengthen Google and Android or signal a culture clash that will kill Google? You ought to have some insights there!
  • RE: Linus Torvalds on Android, the Linux fork

    NEWS FLASH!!! Android is Linux. Android is a Linux fork.

    Quoted in the article:
    "Google?s Android team is very small and over-subscribed to so they?re resource restrained

    If Google is making so much money from Android that they can afford to buy MMI at a 63% premium for $12.5 billion U.S., why can't they afford additional engineering staff members for the Android team? One can conclude that giving back to the Linux kernel is a low priority for Google.
    Rabid Howler Monkey
    • It seems no one knows how to measure the cash generated by Android

      @Rabid Howler Monkey
      Google dumped a wad of money into Android, but no one seems to be able to show how Android is making any money back. Even the folks at Google can't quite show the share holders how the equation works, it's sort of a "Trust Me" thing there.

      Obviously, that leads one to believe that Android is a colossal financial bomb, and now Google was forced to spend $12 billion for Motorola to defend Android. That's a lot of profit to dump into a losing enterprise like Motorola to get control of the patents.

      Now, the shareholders are suing Google because the price isn't high enough. They want a bidding war with MS and Google for those patents.

      Funny if they got the bidding war and Google lost the bid. Then MS would have all the patents and google would have none. I guess that's the price you pay for being stupid, releasing a product that tramples IP rights around the world, and not being prepared.

      Sounds like Google!
      • marketshare is easy to show

        @Cynical99 ... regardless of whose numbers you look at, the Android market is between 30-50% of the mobile computing market (tablets and smartphones). While carriers have the ability to cut their own deals to serve up Bing or whatever as the default search engine, the lion's share (no Apple pun intended) of Android devices still point to Google's servers for search, email and even cloud computing apps. Obviously, that's no coincidence -- Google works hard to make it easy to access its services from an Android device.

        Why? Because if Google didn't have Android, it would be at the mercy of Apple and MS to point users toward Google services. Android allows Google to take matters into its own hands ... at least somewhat.

        That said, I'd agree with @Rabid Howler Monkey: giving back to the Linux community is _not_ Google's top priority. To Google, Linux is a tool that helps them achieve business objectives cost-effectively (or, at least, that was the idea ;-). Google's good about giving back, but they're a business first, and as such they have responsibilities to share holders ... and share holders don't usually care much about giving anything away.
      • RE: Linus Torvalds on Android, the Linux fork

        @jscott69 The following corporations also have shareholder responsibilities: Red Hat, Novell, IBM, Intel, Nokia, Oracle, etc.<br><br>More at the following link (see page 14):<br><br><a href="" target="_blank" rel="nofollow"><a href="" target="_blank" rel="nofollow"></a></a><br><br>Google is certainly not absent from the list of corporations that contribute to the Linux kernel. However, its level of contributions do not mirror other corporations with significant dependence on Linux.
        Rabid Howler Monkey
  • RE: Linus Torvalds on Android, the Linux fork

    Well said. The shareholder suit is a complete joke since they are WAY overpaying for MMI, and these dumb asses are getting a 60%+ premium. If MMI remains as is they will be out of business in 3 years tops.
  • Oh, really! 2016 is it?

    IMHO, all things considered, the 2016 estimate is to far off.

    Right now, many-a-thing's are a-stirring in Off-load Wi-Fi, LIPA et cetera, where the communication needs of both public services and modern man isn't met by TELCO's in any other way than billing.

    Keeping reliable communication up in overload; disaster; remote or riot area's will require some kind of Off-load Wi-Fi and that's where efforts in small home-AP's (Linux) and the recent maneuvers of Google (Android) becomes very interesting and current.

    • RE: Linus Torvalds on Android, the Linux fork

      @scallag how much right now. reliable communication disaster.
  • RE: Linus Torvalds on Android, the Linux fork

    Android is a proprietary and less secure implementation of Linux. I'm avoiding it like the plague as I have no confidence in Google when it comes to fair play, transparency and data security. Google's CEO has demonstrated his utter contempt for personal privacy by scoffing at an individuals right to anonymity. He can go get stuffed as far as I'm concerned.
  • RE: Linus Torvalds on Android, the Linux fork

    Linus Torvalds is making a very big claim, that will clearly NEVER happen!

    Android and Linux have a different motive for their existance, Android is trying to be a commercial product that is 'consumer ready', and linux is not.

    Linux is all about 'freedom' (as defined by RMS) and about sharing and caring :)

    What does linux think is going to happen, is Linux going to move towards ardroid, or is android going to move towards Linux ?

    Linux and Android (one is a kernel, one is an OS) seperated for a reason, and there is no reason for them to come back together.

    All this has done and all it was ever designed to do is further marginalise Linux, and ensuring Linux never makes it on the desktop or on mobiles or tablets.

    Google did not develop Android or folk Linux, they did basically what Torvalds did, they used code from the UNIX base and re-invented the wheel.

    Linux has lost anything like its own identity, you can no longer 'put linux' on your machine, you have to find one of hundreds of fragmented distros, many fragmented GUI's and get to see many people working on the same or almost identical applications and 'windows managers'.

    Groups clearly have gotten to the stage where they need to actually sell their products and deliver to customers what they want, and not what they are told they want, which is what FOSS appears to do.

    the only reason Linux does partially well in the server and backroom world is its cheap and it can do simple things over and over again.

    But ask it to do too much, lick function as a consumer grade desktop and it cannot gain any traction.
    • RE: Linus Torvalds on Android, the Linux fork

      "you can no longer 'put linux' on your machine, you have to find one of hundreds of fragmented distros, many fragmented GUI's and get to see many people working on the same or almost identical applications and 'windows managers'."

      lol So this is why you call yourself 'troll'? Not knowing much about Linux, coming into a Linux thread and posting such a thing. A fine bit of trolling.