(photo by Kernel Diagram from ex_publish)

I think its wonderful and appropriate that Clayton Christensen uses Linux as an example of modularity in software.

 However, as someone who is currently coming up to speed with Linux and all the various distributions the quote from Page 123 of "Disrupting Class" confused me.

 "Linux ia modular system composed of "kernels" that fit together in well-defined ways.  This makes it smple for applicatin developers to design and build their own customized operating system"

More then one kernel working together?? That didn't sound right to me.  Its not. Here is the Wikipedia explaination.

"Linux is a modular Unix-like operating system. It derives much of its basic design from principles established in Unix during the 1970s and 1980s. Linux uses a monolithic kernel, the Linux kernel, which handles process control, networking, and peripheral and file system access. Device drivers are integrated directly with the kernel.

Much of Linux's higher-level functionality is provided by separate projects which interface with the kernel. The GNU userland is an important part of most Linux systems, providing the shell and Unix tools which carry out many basic operating system tasks. On top these tools form a Linux system with a graphical user interface that can be used, usually running in the X Window System."

So one Kernel with lots of other pieces of software that fit together in well defined ways and allow creation of custom operating systems such as Sugar!