Linux基金会发布关于Linux内核的发展报告

许多人还在错误地以为，Linux还是一群黑客在写，这些家伙整天呆在他们父母的卧室里，唯一的社交活动就是在线玩玩角色扮演类游戏，或者在IRC聊天室里为Vi还是Emacs哪个更优秀而打口水仗、抑或为Picard何Kirk谁厉害而争论不休。仅此而已。

最近Linux基金会发布了一份关于Linux内核的发展报告，其中关注的重点是Linux内核的发展方向，最新动态，以及如何做，还有就是谁对内核作出了贡献等。这份报告主要基于Linux内核过去三年时间的开发情况，从2.6.11到2.6.24，最终得出结论：Linux内核开发的主要人员都是由企业所赞助的。

说的更详细点那就是，过去三年中有70%到95%的Linux开发人员对Linux社区所作的开发工作都是有酬劳的，这些费用是由企业支付的，报告还指出，超过70%的内核贡献是以下公司的员工做出的，这些公司主要是：IBM、Intel、Linux基金会、MIPS科技、NontaVista、Movial、NetApp、Novell和Red Hat。

过去的3年中Linux Kernel的开发人员数目也得到了增长，在2.6.11版本的时候只有483人的代码最终被接受到内核中，到2.6.24版本的时候，有超过1057个开发人员的代码被内核代码监护人员所采纳。在过去的三年中，总共有3678名开发人员的代码被Linux内核所接受。

报告认为，即使内核开发人员的数量大量增加，但是做主要工作的的核心开发人员数量并没有增加。过去的三年中，前十名的开发者完成了将近15%的工作，前30 名的开发者完成了30%的工作量。事实上，前五名的开发人员完成了将近8.5%的工作，这些人员是：Al Viro (1.9%内核代码修改); David Miller (1.8%); Adrian Bunk (1.7%); Ralf Baechle (1.6%); and Andrew Morton (1.5%)。

在所有开发者中，有74.1%的开发人员在他们所在的公司从事Linux相关的工作，另外12.9%开发人员从事其他职业，并且他们贡献了10%的内核开发工作，只有剩下的13.9%的开发人员将Linux内核开发作为他们的业余爱好。

所以，作为爱好，Linux爱好者们对Linux内核作出了非常大的贡献，但是企业的开发人员才是Linux开发的主力军，按照对内核开发的贡献，这些企业排名如下：
1) Red Hat, 11.2 percent
2) Novell, 8.9 percent
3) IBM, 8.3 percent
4) Intel, 4.1 percent
5) LF, 3.5 percent
6) SGI, 2.0 percent
7) MIPS Technology, 1.6 percent
8) Oracle, 1.3 percent
9) MontaVista, 1.2 percent
10) Linutronix, 1.0 percent.

另外，咨询等方面的作用对Linux的发展也做出了2.5%的贡献。
这份报告的撰写人包括有Linux内核开发人员，兼LWN创始人Jonathan Corbet，资深Linux内核安全专家Greg Kroah-Hartman和Linux基金会的市场总监Amanda McPherson。
他们在这份研究报告中还指出，报告中所看到的只是这些对Linux开发作出贡献的公司的一小部分，通过长尾理论来看，这些公司的数量非常巨大。同时，他们还指出，这些公司对Linux内核的贡献并不是施舍，从很多事实中我们可以看到，这些公司对Linux内核的改进使得他们在市场中更富有竞争力。

报告指出，除了Linux发行版厂商，比如红帽、Novell和MontaVista外，他们的利益驱使很明显，因为他们推广Linux，是为了更好的市场占有率。他们的下游厂商在对Linux内核的贡献方面也是不遗余力，比如IBM、Intel、SGI、MIPS、Freescale和HP等等，因为他们的硬件可以搭配Linux操作系统来吸引Linux用户，从而增加他们的销售额。

除了上述两类IT企业外，还有Sony、Nokia和三星等消费类电子厂商，他们在他们的硬件产品中使用各种修改后的嵌入式Linux操作系统，比如电视机顶盒、游戏机、摄像机和行动电话等等。他们参与 Linux内核开发的动机也很简单，从中获取相应的Linux内核发展方向，从而为他们的产品软件系统开发获得一个稳固基础。

研究报告还指出，现在的linux发展不仅仅是IT厂商的事情。例如，在最新的2.6.25内核中将包含有PF_CAN（Controller Area Network，控制域网络防火墙设备）协议的实现，而这些代码的实现是由大众汽车公司的开发人员所完成的。PF_CAN可以使得接口统一环境下的各种组件进行可信通信，比如在汽车中的各种电子设备。Linux社区给了大众汽车公司一个很好的开发平台，以便于他们能够实现他们的协议代码，同时，大众公司也发现，将这些代码重新返回到Linux社区中去对他们的技术改进有帮助。

到此为止，你心目中的的Linux开发工程师的形象是不是已经有所变化了，因为现在的linux工程师更像是一个全职的、中上层的传统软件工程师，但是为什么还有各种有关Linux开发人员的流言蜚语呢？McPherson认为，这些都是因为大部分人对竞合开发模式的理解存在问题所导致的。这和过去的模式大不相同了，因为在过去看来，花钱让自己的员工开发程序，让竞争对手无偿使用并且从中牟利简直不可想象。人们还不能从旧有的圈圈中专出来，但是正像研究报告所指出的那样，确实这些支持开源开发的公司从中牟利了，而且这种分享式研发方式将越来越普遍，而且很快，大部分人的脑子就会转过来，拥抱这种开源的开发模式。

原文作者：Steven J. Vaughan Nichols


Linux内核开发所需时间


Linux内核改动频度表




Linux内核大小变化情况





Linux内核变化情况分析
绿色：增加
蓝色：修改
红色：删除




Linux内核开发参与人员数目及分布情况


个人贡献排行榜


公司贡献排行榜




Some people are still under the delusion that Linux is written by unwashed hackers living in their parents' basements whose only social life is playing D&D and having flame wars over IRC (Internet Relay Chat) about whether vi or EMACS better and debating Picard versus Kirk. Nothing, nothing could be further from the truth.

The LF (Linux Foundation) has just released a new report, "Linux Kernel Development: How Fast It is Going, Who is Doing It, What They are Doing, and Who is Sponsoring It." This comprehensive study of the last three years of Linux kernel development, from version 2.6.11 to 2.6.24 releases, reveals that the average Linux developer is being paid by a major corporation to develop Linux.

To be exact, between 70 and 95 percent of Linux developers over the last three years have been paid to work on Linux. According to the report, "More than 70 percent of total contributions to the kernel come from developers working at [such companies as] IBM, Intel, The Linux Foundation, MIPS Technology, MontaVista, Movial, NetApp, Novell and Red Hat."

Over the years, the number of Linux developers has been increasing. Version 2.6.11 had only 483 programmers whose code actually made it into the kernel. The latest kernel, 2.6.24, had 1,057 developers. Over the last three years, 3,678 programmers have had their work included in Linux's core.

That said, the report also stated that "despite the large number of individual developers, there is still a relatively small number who are doing the majority of the work. Over the past three years, the top 10 individual developers have contributed almost 15 percent of the number of changes and the top 30 developers have contributed 30 percent."

In fact, the top five developers, Al Viro (1.9 percent of the total percentage of changes to the kernel); David Miller (1.8 percent); Adrian Bunk (1.7 percent); Ralf Baechle (1.6 percent); and Andrew Morton (1.5 percent), alone accounted for 8.5 percent of Linux's recent code changes.

Of all the developers, 74.1 percent work on Linux for their companies. Of the rest, many programmers—12.9 percent with unknown employers—made 10 changes or less to the kernel. Only 13.9 percent of developers were clearly working on Linux as a hobby.

So, while Linux does have a substantial contribution being made to it by amateurs, the vast bulk of it is being written by corporate programmers. The companies that are building Linux, in order of their contributions to the kernel, are:

1) Red Hat, 11.2 percent
2) Novell, 8.9 percent
3) IBM, 8.3 percent
4) Intel, 4.1 percent
5) LF, 3.5 percent
6) SGI, 2.0 percent
7) MIPS Technology, 1.6 percent
8) Oracle, 1.3 percent
9) MontaVista, 1.2 percent
10) Linutronix, 1.0 percent.



In addition, consultants' efforts have counted for 2.5 percent of the total work on Linux.

The authors of the study, Linux kernel developers Jonathan Corbet and Greg Kroah-Hartman, and Linux Foundation Director of Marketing Amanda McPherson, also note that, "What we see here is that a small number of companies are responsible for a large portion of the total changes to the kernel. But there is a 'long tail' of companies which have made significant changes."

They also point out in the study that "none of these companies are supporting Linux development as an act of charity; in each case, these companies find that improving the kernel helps them to be more competitive in their markets."

Besides Linux distributors, like Red Hat, Novell and MontaVista, where the profit motive is clear, the study also finds that "companies like IBM, Intel, SGI, MIPS, Freescale, HP, etc. are all working to ensure that Linux runs well on their hardware. That, in turn, makes their offerings more attractive to Linux users, resulting in increased sales."

Other businesses that work on developing Linux, "like Sony, Nokia, and Samsung ship Linux as a component of products like video cameras, television sets, and mobile telephones. Working with the development process helps these companies ensure that Linux will continue to be a solid base for their products in the future."

It's not just IT companies these days that are working on improving Linux. For example, the study's writers state that "The 2.6.25 kernel will include an implementation of the PF_CAN [Controller Area Network] network protocol which was contributed by Volkswagen. PF_CAN allows for reliable communications between components in an interference-prone environment—such as that found in an automobile. Linux gave Volkswagen a platform upon which it could build its networking code; the company then found it worthwhile to contribute the code back so that it could be maintained with the rest of the kernel."

So since your typical Linux developer is more likely to be a full-time, upper-middle class software engineer, why does the FUD about Linux developers still hang on? McPherson believes it's because "it's difficult for most people to get their minds around competitive mass collaboration. It's obviously a huge shift from the command and control models of old. Most people seem to have a hard time understanding that companies will pay people to work on software that their competitors use and profit from."

McPherson continued: "People are still stuck in the zero sum game of the past. But now, with papers like this, they can see that companies who support open source actually profit through a shared R&D cost. The myth persists but as open source is becoming more common than proprietary development; I think you'll see a shift in understanding."