In the Beginning... Was the Command Line
Fully titled "In The Beginning Was The Command Line", this lengthy essay was originally published online and was only later made available in book form. Ostensibly a commentary on why Microsoft's operating systems business is unlikely to remain profitable forever in the face of competition from Linux, it also lucidly analyses the corporate/collective culture of the Microsoft, Macintosh, and free software communities, explores the GUI-as-metaphor, and explains the beauty hackers feel in good-quality tools.
Stephenson spends some time discussing Debian and its impressive bug-tracking system in the essay. Debian developers were extremely chuffed to find out that an author that many of them enjoy uses and approves of their own work.
The full text is still available at http://www.cryptonomicon.com/beginning.html