PS2 vs USB 2.0

[DarrickCZ]

I have question:

 It is USB keyboard betther then PS2 Keyboard? It is any benefit? Still planty New Motherboards have PS2 conector. In my expirience i find PS2 have falls as bad conection keyboard dont work and you unplug and plug in and she magickly (witch craft, keyboardreparo) works.

 It is any Test between PS2 and USB?

Please send messege with explayning or make fast as possible or video with this issue or send mi link on youtube if this is somewere.

[mariushm]

ps/2 is not designed to be hot plug , you're not supposed to pull it out and plug it back in and just work. The default would be to not work until you restart the pc with the ps/2 connector plugged in.

 

ps/2 has its advantages but also some disadvantages.

 

One of the big benefits is in theory the lower latency... usb is designed to poll devices by default at 125 hz, meaning the usb drivers "ask" the usb keyboard up to 125 times a second or every 8 ms if new keys were pressed and the keyboard then says yeah the following keys were pressed.

So in worst case scenario there can be up to 8ms of time between your key presses and the moment the keys are actually received.

Just like with mice, you can raise that poll rate to 1000 hz, meaning 1 read every ms... but that increases cpu usage.

 

ps/2 can be more responsive (less than 8ms latency by default), but at the same time you have less power on the ps/2 connector, you lose benefits like programmable buttons (harder to do with ps/2) or rgb lightning on keys, or volume knobs on keyboards, or keyboards  with analogue keys (programmable threshold for key presses etc etc)

 

[Arphis]

Found it

 

https://www.youtube.com/watch?v=AWkvzycD5PE

 

One reason they are still in use, not well explained in the video:

 

Some people/companies are afraid of data theft via usb-ports and disable them, sometimes even physically. So PS/2 is the only way to connect an input device.

[Mira Yurizaki]

On 1/18/2020 at 4:36 AM, DarrickCZ said:

It is USB keyboard betther then PS2 Keyboard? It is any benefit? Still planty New Motherboards have PS2 conector. In my expirience i find PS2 have falls as bad conection keyboard dont work and you unplug and plug in and she magickly (witch craft, keyboardreparo) works.

In modern times, no, there's no practical benefit for a regular consumer. The only reason they exist is there's still a sizeable market of people who use PS/2 based keyboards.

 

Though heck, modern motherboard still provide something for older interfaces. Mine has a header for RS-232 serial and the parallel port, for whatever hardware I might just have that I need. To be fair though, I think Linux defaults output to a serial port if there's no display hardware available.

[mariushm]

On 1/19/2020 at 2:57 AM, Arphis said:

Some people/companies are afraid of data theft via usb-ports and disable them, sometimes even physically. So PS/2 is the only way to connect an input device.

it's kinda silly, because one could easily modify a ps/2 keyboard to infect a pc (dump a program in pc) or to steal data (but very very slowly)

ex open a console and press a hidden button or a combination of keys on the hacked keyboard, and the keyboard starts typing the binary application in console (saving it to disk ex copy con file.exe )

Program could send data to the ps/2 keyboard by sending commands to the ps/2 keyboard (turn num lock , caps lock etc leds on or off)

 

You can do this by hiding a 1-2$ microcontroller and a SD card inside a keyboard...