Comment by jacquesm
Imagine a world where the Apple II had a 6800 later upgraded to 6809...
Imagine a world where the Apple II had a 6800 later upgraded to 6809...
Though a problem, as you point out, it still happened. The 6800 based SWTPC was followed by 6809 machines what need to have all their software reassembled.
On the other side of the cpu wars, all those 8080 machines moving on the Z80s got to keep all their binary software, which happened again for IBM PCs and clones as those evolved.
It wouldn't have happened because the 6809 wasn't binary compatible with the 6800.