I missed this the first time around: PEEK and POKE are anathema to modern OSes, which demand to control all memory access and keep programs within little memory ‘boxes’ from which there is no escape. You could implement the rudiments of PEEK and POKE with the equivalent of a big array, but your actions within that array wouldn’t have any interesting effects on the hardware. The only thing you could do is create machine language programs byte-by-byte and then execute them, something done much better with a good syntax for inline assembly.