The expansion port for the C64 has a lot of pins corresponding to ... It doesn’t really matter, though, as we don’t know if [Rob] has the 1541 disk drive that makes this cart useful.

Once upon a time, you might have developed for the Commodore 64 using the very machine itself. You’d use the chunky old keyboard, a tape drive, or the 1541 disk drive if you wanted to work faster.