Software is full of circular dependencies if you look deep enough. Compilers written in the language they compile are the most obvious example, but not the only one. To compile a kernel, you need a running kernel. Linkers, build systems, shells. Even text editors, if you want to write the code instead of just downloading it. How do you break this cycle? Since the bootstrapping problem has first come to my attention, I've been drawn to this unique area of software engineering. Not out of fear that someone would try to implement a trusting trust attack, but simply as an interesting challenge.