Hello ve3id:
You are right about one thing -- nobody in the aviation world uses Microsoft Windows, or any other widely-used operating system, in airborne components. They write their programs directly in "machine code", or perhaps an assembler that is the humanized version of machine code. Nevertheless, the software designers have no choice but to use the "instruction set" that their chosen processor is based on. The 80286 has 200 or so basic codes in its instruction set. That's all she's got. Furthermore, the designer is constrained to use the "architecture" of that processor. The 80286, and its successors, have one kind of architecture (Von Neumann), in which the program, data and stack all occupy the same addressable memory. Not at all like the Harvard architecture found in many microprocessors. This has nothing to do with Windows.
Remember the descent of the Eagle to Tranquility? The 1201 and 1202 codes that scared Armstrong and Aldrin denoted exactly the kind of hardware limit I described. Luckily for them, whatever Interrupt Service Routines were being skipped because of the overload were low priority, so the landing continued.
(Incidentally, I'm va3aol.)
YYZjim