The thing about the TI powerbook was, it didn't have to be plugged in to hot swap the battery. You could do it when running on battery power. (It had a tiny internal battery, that could run it for like 20-30 seconds, so long as the screen was closed).

It did also run when plugged in with the battery removed, which is good 'cause the battery eventually failed. So this way I can still run it.

Oh! Cool!