Very long-time developer, focusing for some time on the Microsoft development universe. I've been a researcher at USC/ISI, was on the ANSI X3J13 Committee that produced the CommonLisp standard, and have worked in many industries and sectors, from bare-metal assembly language, to entire operating systems, or major parts of them. I was a principle developer, along with 3 others, of one of the most advanced LISP hardware systems developed, including an interface-based, DI-structured file system that allowed a variety of different access models to be plugged in (this was in the mid-80s, long before that was a recognized pattern), and deep development of the extensive "mix in" styles of object inheritance found in such systems. I've developed several other implementations of languages, including 3 other versions of LISP (one commercial, the rest were for research). APL, and Smalltalk.