> So, even if highfalutin phrases like “virtual machine” weren’t yet tripping off the tongue of the average bedroom hacker, it wasn’t hard to divine what Infoco

> So, even if highfalutin phrases like “virtual machine” weren’t yet tripping off the tongue of the average bedroom hacker, it wasn’t hard to divine what Infocom must be doing in the broad strokes. The specifics, however, were another matter. For, while Infocom didn’t hide the existence of a Z-Machine in the abstract, they had no vested interest in advertising how it worked. ... But plumbing the depths of a virtual machine whose very existence was only implicit was hard work This is extremely misleading. Sure, some of the depths weren't published, but Infocom published how the Z-machine worked in a variety of forums. Most accessible is "How to fit a large program into a small machine" by Marc S. Blank and S. W. Galley, published in Creative Computing, 1980. Creative Computing was widely read at the time. It explained how integers and strings were stored as well as the general approach. Blank was one of the key developers of Zork. You can view the paper here: https://mud.co.uk/richard/htflpism.htm https://mud.co.uk/richard/htflpism.htm Of course, it took some effort to work out the exact opcodes, but there was a lot of publicly-available information to start from.