Jinxter wrote on 2021-04-01, 20:58:
This was very informative. Thanks. So what about using a mouse on the same port, what kind of mouse? Is it the same as something we know - like the Amiga, or Atari mouse? What about driver?
Yes, it is something we know but probably not what you'd expect: it uses the BUS mouse interface (derived from Microsoft's InPort).
There is a driver (mouse.sys) included in the "Works" floppies that came with the PC, a simple DEVICE=MOUSE.SYS suffices. I haven't tried other bus mice with this driver as I don't have any, and I also don't know about the opposite (other bus mice with their own driver on that port). In theory they should but who knows... I attached the driver just for it to exist here, it has a MS copyright "Microsoft (R) Mouse Driver Version 6.14".
You can always use a serial mouse of course.