Changing the size of memory or changing the ROM version forces a reset of the PET.
The emulator has an IEEE-488 device at address 8. It can be used load and save (.prg) files.
Some programs don't run on ROM1 and some require more memory than the default 8K.
The flyer tells us that CALC is everything you ever wanted in an $800 calculator. The joke, of course, is that the PET's introductory price was $795 USD in 1977 (equivalent to just shy of $4,000 in 2024). Joke's on you, you gormless rube, using your very expensive machine as a calculator.
The calculator has some interesting features like octal/decimal/hexadecimal conversion and the ability to treat the results of a calculation as a memory pointer and PEEK at bytes and words at the target memory location.