geekhack
geekhack Community => Keyboards => Topic started by: kohan69 on Tue, 12 July 2011, 18:43:30
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PS/2 is gone in many modern motherboards.
For example, I'm planning a sandy bridge build and the pro version doesnt have a ps/2 port:
http://www.microcenter.com/single_product_results.phtml?product_id=0364206
only the deluxe one does:
http://www.microcenter.com/single_product_results.phtml?product_id=0366668
has any one tried pci cards or similar like this?
http://www.newegg.com/Product/Product.aspx?Item=N82E16815150153&cm_re=pci_ps%2f2-_-15-150-153-_-Product
I just want to make sure the latency doesnt increase compared to onboard ps/2 and that it fully support NKRO
a PS/2 keyboard has its own IRQ slot, no polling of any kind - will that also be the case here?
I couldnt find any other threads regarding this, please link if already discussed, thanks!
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I'd just build one of these (http://geekhack.org/showwiki.php?title=Island:17458) and be done with it. Hopefully they will release a kit at some point.
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Personally, I prefer this one: http://geekhack.org/showwiki.php?title=Island:14618
I think it will be the basis for the inline colemak/dvorak converter, as well, which I believe will eventually be released as a kit, or at least we will have parts lists.
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is n keyrollover going to cease to exist once motherboard manufacturers stop including the ps/2 connection on modern motherboards?
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is n keyrollover going to cease to exist once motherboard manufacturers stop including the ps/2 connection on modern motherboards?
There are fully functional 18 key rollover USB controllers out there, so probably not.
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There are fully functional 18 key rollover USB controllers out there, so probably not.
ahhhh. so the limitations of keyboards plugged in via usb in regards to # key rollover is more so a .....uhhhh...... technology hasn't been developed/implemented yet type of thing?
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Custom built adapters allow NKRO over USB, the one designed by Soarer that I use with my 122 certainly does. The 6+4 limitation is largely arbitrary.
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ahhhh. so the limitations of keyboards plugged in via usb in regards to # key rollover is more so a .....uhhhh...... technology hasn't been developed/implemented yet type of thing?
Why put time and money into designing something most people will never use?
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Custom built adapters allow NKRO over USB, the one designed by Soarer that I use with my 122 certainly does. The 6+4 limitation is largely arbitrary.
true, i suppose it's difficult to think of any instances when you'd need more than 6 key rollover for any sort of use that isn't extremely specialized. it's more so a novelty/status type of vibe i'm getting from keyboards boasting about n key rollover.
Why put time and money into designing something most people will never use?
hah, touche.
while it isn't something i'm necessarily worried that keyboard manufacturers aren't producing or putting effort into. or bummed that ps/2 connections may eventually die out completely. i was more or less just asking out of curiosity.
i also feel like the superiority of ps/2 over usb is more so about about "PS/2 keyboards aren't polled, but are completely interrupt based. And third, it is impossible for it to be delayed by the USB bus being used by other devices." as opposed to key rollover limitations vs no key rollover limitations.
direct quote from the mechanical keyboard guide above.
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I'm not going to bother with PS/2 for my new Leopold, 18KRO over USB without any multi-keyboard shenanigans in Windows.
If the motherboard you want to buy doesn't have PS/2, there's no way of adding a port via cards that will act the same way. The only way would be if the motherboard had a vacant spot for the PS/2 connector on the PCB, and you soldered it in (and hopefully the BIOS recognizes it, could be disabled).
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Well, except for the use of the word "third" it seems quite accurate to me. USB is a CPU based polled serial protocol, PS/2 is hardware interrupt based. That means that USB keyboards drain away a minute fraction of your CPU whether they are being used or not. PS/2 only drains CPU when you actively push the key.
Now, this makes 0 practical difference when you're actually USING the keyboard. It only matters when you aren't. And even then, barely at all.
But if you are saturating your USB bus, it can have a negative impact on other devices on the bus, including mice and keyboards. Though I haven't seen that happen on hardware younger than 10 years old or so.
So yeah, it's basically a non-issue. The only advantage PS/2 has in my mind is better support for 122 key keyboards.
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true, i suppose it's difficult to think of any instances when you'd need more than 6 key rollover for any sort of use that isn't extremely specialized. it's more so a novelty/status type of vibe i'm getting from keyboards boasting about n key rollover.
The only time I run into it myself is games that use two hands on the keyboard. In Descent 3, for example, the 1 key does not get recognized when you're also Dual-chording, sliding, firing primaries, secondaries and using the afterburner at once. How am I supposed to fire mah lasers if I can't use the 1 key? :laser:
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That sounds alot like a joystick game to me then. Like wing commander.
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The only advantage PS/2 has in my mind is better support for 122 key keyboards.
NO is not the only advantage, PS2 is a life saver when a MB is swapped because the PS2 drivers is loaded as a legacy device and doesn't need a PnP driver.
In other words it always work. This is not a problem under Linux, but the vast majority of the users are still using windows, Linux users included.
then an unused PS2 connection in favor of an USB port is a waste of resources, the usb devices are every day more common and the USB plugs are like Money and HDD space, they are always not enough...
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true, i suppose it's difficult to think of any instances when you'd need more than 6 key rollover for any sort of use that isn't extremely specialized. it's more so a novelty/status type of vibe i'm getting from keyboards boasting about n key rollover.
Oh yeah? Try playing 2 player fighting game, sharing one keyboard. Until I found out about NKRO I couldn't figure out why I couldnt do certain moves when a friend and I were playing!