Estimating development costs

Estimating development costs

Posted Jan 9, 2006 15:06 UTC (Mon) by dwheeler (guest, #1216)
In reply to: Winning the Linux Wars (MCP) by ayeomans
Parent article: Winning the Linux Wars (MCP)

Thanks very much for the reference! The paper referenced above measured only the kernel. If you want to examine the whole OS, you could look at my paper More than a Gigabuck: Estimating GNU/Linux's Size (June 2001). Here are a few interesting facts quoting from the paper (which measures Red Hat Linux 7.1):

1. It would cost over $1 billion (a Gigabuck) to develop this Linux distribution by conventional proprietary means in the U.S. (in year 2000 U.S. dollars).
2. It includes over 30 million physical source lines of code (SLOC).
3. It would have required about 8,000 person-years of development time, as determined using the widely-used basic COCOMO model.
4. Red Hat Linux 7.1 represents over a 60% increase in size, effort, and traditional development costs over Red Hat Linux 6.2 (which was released about one year earlier).

Someone else, inspired by my paper, wrote the very interesting paper Counting Potatoes: The size of Debian 2.2; they found that Debian 2.2 includes more than 55 million physical SLOC, and would have cost nearly $1.9 billion USD using over 14,000 person-years to develop using traditional proprietary techniques.

Obviously Red Hat Linux 7.1 and Debian 2.2 are quite old. Red Hat 7.1, for example, didn't include massive packages like OpenOffice.org. So the actual development costs of current implementations would be even greater. And note that these only estimate replacement cost, not value. A lot of research has gone into developing competing approaches and new ideas, and if only the "winner" went in, the effort that went into the alternatives isn't counted (and it really should be, because those alternatives cost time and caused a better result).

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