(or, "Thunderclouds Gather on the Horizon") On a couple of occasions, people have responded to my original essay with the comment that what I've created by the end isn't really an ELF executable. Rather, it is a file that the Linux kernel, in its current incarnation, happens to mistake for an ELF executable. It's a fair point. That 45-byte file clearly doesn't conform to numerous requirements of the ELF specification. But can you blame me? How could I have stopped at the point just before I tossed the ELF specification out the window, knowing what might still be possible? But to satisfy these purists, and the puritan side in all of us, I've created this sequel. So. We have an executable that we whittled down to 45 bytes. We now want to bring it into rigid conformance with published standards, while still keeping it as small as possible. The point at which we strayed from straight and narrow path was when we started fiddling with "unused" fields in the ELF header.…