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.
BOP is a drill program to help learn Chisanbop, a Korean finger-counting system that allows you to encode numbers up to 99 on your fingers. There was a real media hype cycle around Chisanbop in the late 1970s—I can remember segments on news magazine shows where the presenters eagerly informed us that the system would revolutionize mathematics instruction. The hype died down around 1982 or so and we don't hear much about Chisanbop in North America today.