I'm mainly a system administrator, not a programmer, worked ten years as a WAN network administrator (IBM VTAM SNA/SDLC).

In the time I struggled with many and many kinds of systems and programming languages, remaining on the "bottom" of the programming experience (e.g. more shellcode and C than objects and abstractions, more to the Machine Language than LISP or Prolog).

Thus I can say I (partially) know all... and I well know nothing. ;-)