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Comment by MartinCron | Hacker News Reader

My goodness, that thing has a PS/2 keyboard port. Maybe I can drag my first-generation Microsoft natural keyboard out of retirement.

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Some gamers still prefer PS/2 if given the choice, even though there's little technical advantage. Although their most cited reason (key rollover) isn't valid; the keyboard determines how many simultaneous key presses it will transmit over USB.

Huge advantage. Whip out that 5lb Model M and get to clicking. Typing on an original right now.

n key rollover is determined by the keyboard and the connector, if the keyboard supports it and your interface is PS/2 you do get full rollover.

http://superuser.com/questions/16893/do-usb-or-ps-2-keyboard...

PS/2 keyboards observationally are known to have a bit less latency. Since there are a ton of variables at play (keyboard controller, USB poll rate, PS/2 interrupt queuing, etc.) it's hard to evaluate just how much the difference will be with any given setup.

It seems it's less about what the keyboard sends, and what the standard protocol allows:

http://geekhack.org/index.php?topic=5572.msg85020#msg85020

I'm sure a keyboard could set up their own driver that allows more key presses, but that's certainly not the standard.

Max Keyboard were the first to crack N-Key rollover over USB. Can't say enough about their NightHawk X8...

http://www.maxkeyboard.com/max-keyboard-nighthawk-x8-blue-ba...

My understanding of how n-key rollover was finally implemented in USB keyboards was by putting a USB hub in the keyboard and having the keyboard pretend to be several keyboards all at once.

The only ways to get n-key rollover over USB are through dirty hacks (like USB hub emulation) or through non-standard drivers. It is an issue.

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