No, it never did. The 8042 isn't inside the keyboard but on the motherboard, and the status register inp(100)&2 is clear even when there isn't a keyboard atta

No, it never did. The 8042 isn't inside the keyboard but on the motherboard, and the status register inp(100)&2 is clear even when there isn't a keyboard attached. The way the BIOS detects a keyboard is by sending a command from the 8042 to the keyboard (usually 255; reset and do basic test) and waiting a few seconds for the ACK. Users often used the keyboard in those days and might want to know that the keyboard itself wasn't plugged in or working before booting up the computer because the keyboard lines (while often robust) didn't actually support hotplug and plugging in a keyboard while the controller was trying to talk to it could actually damage the computer. Meanwhile some other people used PC hardware as something other than a PC, and in those cases might not want a keyboard attached that can get damaged, so most BIOS actually let you disable the keyboard startup test.