大家知道，自启动U盘里面实质上就是一个Linux发行版，简单说来，就是一个操作系统内核加上一个应用软件包。它的开发成本有多高？2002年，David A. Wheeler本人设计了一个估算程序源代码行数（比如，除去注释行，｛......｝多行源代码只算做一行源代码，等等）的函数SLOCCount，再根据所谓“COCOMO”模型，精确估算一个Linux发行版的开发成本。这里，“COCOMO”是COnstructive COst MOdel双字头缩写组合词，意思是“构造成本模型”，通俗一点说，COCOMO模型就是使用传统软件开发方式，一个程序的开发成本依赖于该程序的源代码行数的“指数型”经验公式（必须经过大量的实例验证）。当年，Wheeler对红帽Linux 7.1发行版内核的估值是12亿美元，不包括该发行版中的其他应用程序。

         如今，考虑到Linux内核的不断升级和人力成本的增加等因素，《Linux基金会》决定重新赞助这一研究项目，由Amanda McPherson，Brian Proffitt和Ron Hale-Evans组成三人小组共同进行这项研究，最近发表了研究报告，题为“Estimating the Total Development Cost of a Linux Distribution。”毫无疑问，这份研究报告很有参考价值。

         报告指出，遵循Wheeler开创的研究途径，参照2008年美国人力成本，Linux内核的开发成本为14亿美元（相当于7,500人年），而一个发行版中的应用软件包（相对于60,000人年）的开发成本约为94亿美元，共计108亿美元。实际上，现今的Linux内核是由散布在全球的3,200多人(分布在200多个公司)长年累月的研究成果。我们说，Linux发行版的价值就在于它遵守“自由再分发”的原则，可供全球人们自由地使用（当然完全是免费的），而不仅仅在于其开发成本是多少多少。据有关报道，俄罗斯中学（在2010年前）都必须全部使用自由软件。让我们设想一下，如果俄罗斯的每一位学生都有一个自启动U盘（无论什么Linux发行版），这对于俄罗斯而言，是何等的财富（成本的节约就是财富）！

        自启动U盘是一种客观发展趋势，由此催生出的公共场所的“无盘网吧”更是一种历史的必然。对于Ubuntu 8.10而言，自启动U盘的制作只是一次击键操作（激活USBLive工具）而已，

（    注：根据这项研究，现今的Linux内核共有6,772,902行源代码，价值（开发成本）为1,372,740,206美元。）

           该项研究的结论，写得十分精彩，特附于文后，供大家分享。

袁萌 10月25日清晨

附：Linux发行版开发成本研究报告的结论（原文）

Conclusions

So do we now know what Linux is “worth?” While it may not be a question capable of being answered completely, some things are very clear: The true value of Linux springs from the ability to re-use it and the tremendous flexibility that it creates.

Just imagine a computing world where Linus Torvalds didn’t allow (in fact force) users of Linux to allow others to re-use their contributions. Would there be a Google if they didn’t have the free use of Linux and the ability to modify it to suit their needs? Could there be the expanding new category of sub-$350 ultra mobile PCs without the free use of a $10.8 billion piece of software? Would Amazon be able to build its new line of Kindle reading devices without a free piece of $1.4 billion R&D to power it? More than just money, the software in a Linux distribution represents time. The economics in each of these examples would not have been possible had these companies been forced to pay per-device or per-server license fees to any one company or had to devote the thousands of person-years of development time to create this software.

What can we learn from this study? The substantial development costs represented in a community-based Linux distribution reflect its increasing value and importance in the world of computing. The companies and individuals who work on Linux-related projects and build this value profit by sharing the development burden with their peers (and sometimes competitors.) Increasingly it’s becoming clear that shouldering this research and development burden individually, as Microsoft has done, is an expensive approach to building software. While monopoly position in the past has allowed them to fund this massive development, we believe that in the future competition from collaborative forces will make such an isolated position untenable.

As we can see from this study and through the explosion of Linux throughout all areas of computing, collaborative development creates enormous economic value. Companies such as IBM, Intel, HP, Fujitsu, NEC, Hitachi, Google, Novell, Oracle, Red Hat, and many others have all participated and profited in the tremendous ecosystem created by this open model of software development. But make no mistake: while companies are participating, individuals are just as important in the expansion of this software and its value. That’s how it all began after all.