It's not that data really _has_ to be aligned. It's that computers are easier and cheaper to design and manufacture if they require data alignment. Consider t

It's not that data really _has_ to be aligned. It's that computers are easier and cheaper to design and manufacture if they require data alignment. Consider that it would be straightforward for today's 64-bit CPUs to permit 64-bit values to have one-byte alignment. There's all kinds of ways to implement that in hardware and software, but to do so requires extra circuitry, that would require larger silicon dies, there would be a greater failure rate at the fab and so on.