[xubuntu-users] no ps2 mouse?

Ralf Mardorf ralf.mardorf at rocketmail.com
Thu May 1 03:55:32 UTC 2014

On Wed, 2014-04-30 at 20:31 -0300, Bruno Benitez wrote:
> Remember that ps2 devices are not plug'n'play, you need to boot with
> said devices atached to the computer.

That's wrong, at best it's a half-truth.

"Sometimes, devices that would be hot-pluggable may appear to only be
cold-pluggable because of deficiencies in the system software. For
example, PS/2 pointer devices are generally hot-pluggable (although they
are not designed to be), but Microsoft Windows 95 and related operating
systems would commonly have to be rebooted every time a PS/2 mouse was
replaced, in order to detect the new mouse." -

PS/2 ports are designed to connect the digital I/O lines of the
microcontroller in the external device directly to the digital lines of
the microcontroller on the motherboard. They are not designed to be hot
swappable. Hot swapping PS/2 devices usually does not cause damage
because more modern microcontrollers tend to have more robust I/O lines
built into them which are harder to damage than those of older
controllers; however, hot swapping can still potentially cause damage on
older machines, or machines with less robust port implementations.

If they are hot swapped, the devices must be similar enough that the
driver running on the host system recognizes, and can be used with the
new device. Otherwise, the new device will not function properly. While
this is seldom an issue with standard keyboard devices, the host system
rarely recognizes the new device attached to the PS/2 mouse port. In
practice most keyboards can be hot swapped but this should be avoided.

PS/2 connectors are not designed to be plugged in and out very often,
which can easily lead to bent or broken pins. PS/2 connectors insert in
only one direction and must be rotated correctly before attempting
connection. Most but not all connectors include an arrow or flat section
which is usually aligned to the right or top of the jack before being
plugged in. The exact direction may vary on older or non-ATX computers
and care should be taken to avoid damaged or bent pins when connecting
devices. This issue is slightly alleviated in modern times with the
advent of the PS/2-to-USB adapter: users can just leave the PS/2 plugged
into the PS/2-to-USB adapter at all times and not risk damaging the pins
this way." - https://en.wikipedia.org/wiki/PS/2_port

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