How to make the keyboard press keys simultaneously on two computers without additional software?

Question

Keyboard

There is one keyboard and it needs to simultaneously press a button on 2 computers.
For example, we programmatically transfer a keystroke from one computer, and it is pressed on another.
Is it possible without software?
If it is even easier to formulate, is it possible to programmatically transfer a keystroke from the first computer to the keyboard while it is connected to the second computer?

Answer 1

Make your physical keyboard out of two arduinos, each pretending to be a separate keyboard.
Two shoelaces for computers.
One button that closes the GPIO pins on both boards at the same time is better with galvanic isolation.
A button was pressed, each arduino tracked the press and sent a key/key combination to its computer.

Answer 2

Write your own keyboard driver or modify an existing one.
https://habr.com/en/post/139593/