[CS-FSLUG] Kernel worth hundreds of millions

[Fred A. Miller]

Kernel worth hundreds of millions

By Egan Orion
<http://www.theinquirer.net/articles/flameAuthor/gb/inquirer/news/2008/10/22/linux-source-code-passes>:
Wednesday, 22 October 2008, 5:55 PM

*THE NUMBER* of lines of source code comprising Linux kernel files
recently surpassed the ten million mark after the latest release of
Linux version 2.6.27, an analysis has found.

However, that count includes blank lines, comments and text files
included in a full checkout of the kernel source. Counted slightly
differently, the number of lines of actual text is "only" over nine
million, but we rather like that larger figure of ten million, because
white-space really is important for code readability and, well... it's a
nice round number..

As with all long-term programming projects, the size of the Linux kernel
code base varies over time, as old code is discarded and replaced.

Newer features and functions are constantly being added, though, so the
overall size of the Linux kernel continually increases.

Some analyses of the Linux kernel code base using David Wheeler's
/SLOCCount/ program yield some interesting facts. (The acronym "SLOC"
stands for Source Lines of Code.) It finds only 6,399,191 lines of
source code, since it doesn't count blank lines, comments and other
input. One breakdown of the code base by SLOCCount comes up with the
following figures (percentages are rounded to one decimal place):

TYPE

	

COUNT

	

PER CENT

Drivers

	

3,301,081

	

51.6

Architectures

	

1,258,638

	

19.7

Filesystems

	

544,871

	

8.5

Networking

	

376,716

	

5.9

Sound

	

356,180

	

5.6

Include

	

320,078

	

5.0

Kernel

	

74,503

	

1.2

Memory Mgmt

	

36,312

	

0.6

Cryptography

	

32,769

	

0.5

Security

	

25,303

	

0.4

Other

	

72,780

	

1.1

Categorisation by language finds that the overwhelming majority of the
Linux kernel code is written in ANSI C, at 96.39 per cent, with Assembly
Language accounting for almost all of the rest at 3.32 per cent. Other
languages used in the kernel source files, in descending order of the
number of lines of code, include Perl, C++, Yacc, Sh(ell), Lex, Python,
LISP, Pascal and Awk.

More interestingly perhaps, SLOCCount also produces an estimation of the
Linux kernel source code's value, that is, what it might cost to
redevelop the code base from scratch, using the COCOMO development model.

SLOCCount estimates that it would take a team of over 200 developers
about nine and a half years to rewrite the Linux kernel from scratch.
Based up a four year old assumption of programmers' average salary
level, SLOCCount calculates that would cost nearly $268 million.

Given inflation and adding in management overhead, $500 million might be
a fair estimate of what it might actually cost a proprietary software
vendor to redevelop Linux.

In fact, thousands of programmers have contributed to developing the
Linux kernel, over a period of more than 15 years.

And in terms of what it costs one to download a full Linux distribution,
they did for free. µ


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