A device which uses command protocol to inspect functioning of the CPU (including memory) is called a debugger.
it is always worth keeping this quote in mind; there's a reason it is still remembered 150 years after it was written...
When I use a word,’ Humpty Dumpty said in rather a scornful tone, ‘it means just what I choose it to mean — neither more nor less.’ ’The question is,’ said Alice, ‘whether you can make words mean so many different things.’ ’The question is,’ said Humpty Dumpty, ‘which is to be master — that’s all.