I'm curious about how memory mapping works on the Macintosh. On reset, the 68k loads from $000000, so the ROM must be there in some way when the machine boots. Some magic happens afterwards, and then when the system is running, the ROM is present in the address range $400000 - $41FFFF. How does this address translation work? What device provides that functionality? Any details would be appreciated. I'm learning about computer architecture, and this topic has me somewhat perplexed.