It was a design decision of QNX that the kernel never uses strings. Everything the kernel handles is fixed length, except messages, and messages go from one user process to another. The kernel does not allocate space for them. I think they go that right.

There's a QNX user process that's always present, called "proc", which handles pathnames and the "resource managers", programs which respond to path names. But that's in user space, and has all the tools of a user-space program.