feedmegin posted:

Well, 16 bit data lines. Original 68k at an architectural level had a 32 bit address space but only ran out 24 address lines (limiting maximum addressable memory to 16 megabytes) - the top byte in an address would thus be ignored. This caused problems down the line when addressable memory was increased because people would use that top byte for stuff like type tags; a similar thing happened with early ARM, which is why modern 64 bit architectures that don't use all their theoretical address space specify exactly what the unused bits should be and fault if you put anything else in there.