N-key rollover test.

[bhtooefr]

OK, it fails ERT (at least) on my Dell with an Intel CA810E motherboard and Ubuntu 7.04, connected via PS/2, as well.

I was going for minimum, not maximum.

[pex]

Unfortunately Unicomp don't currently make or plan to make a model that will recognise more keys.

I thought they would fabricate you anything you wanted.  They may not mass produce such a model.

I was going for minimum, not maximum.

Maximum is important for establishing that a keyboard will push through at least that many keys potential, but is wholly unimportant for practical uses because the keys are most often awkward choices on the keyboard for any use.

Minimum means there is at least one failure of choice.  Choice is the whole point to rollover.

[iMav]

I thought they would fabricate you anything you wanted.  They may not mass produce such a model.

They won't even bother unless you are going to be buying a LOT of them.  I've spoke with them about a couple of different custom ideas and they were totally uninterested as I was not going to be buying 1000's of them.

If you want some different keycaps...sure, they will likely help you out.  But if you want a different layout or anything else major...good luck.

[zerogravitas]

EPS branded Fujitsu FKB4700 (bought off ebay for $1)

Failed on "uio" and "qws" so far.

[ecru]

Focus Electronics FK6200 (branded EZ KEY), no date on label or cast in the plastic
Interface: 5 pin DIN replaced with ps/2
Operating System: Debian Lenny - dvorak layout
5 key rollover - ',.aoe test (qweasd for sholes users)

notes
Rubber dome with spring loaded striker - looks like a black switch with white sliders at first glance.
Feels much less crisp than Unicomp 42H1292U or black alps with white sliders, but better than typical rubber domes.  Keycaps are wobbly too.

[IBI]

Raptor-Gaming K1. Passes QW AS and QWE ASD, gives QWERAS on QWER ASDF

I'll post details later, first impressions are excellent though.

[Warm Woolly Sheep]

Logitech Classic Keyboard 200
Model: Y-UR83
Interface: USB
N-key-rollover: 6
keys used: qasdew

Bought it for $20 at office max while I wait for my endurapro to arrive.

[iMav]

Bought it for $20 at office max while I wait for my endurapro to arrive.

I'm quite fond of my EnduraPro.  I think you will be pleased with it.

BTW, Welcome to GeekHack!  

[bigpook]

What is the point of knowing your n-key rollover?
What practial purpose does it server?

[zillidot]

What is the point of knowing your n-key rollover?
What practial purpose does it server?

One may also ask what's the point of spending $200 on a keyboard.

Seriously though, one thing it's useful for is gaming. Games sometimes require pressing multiple keys at once, often in a cluster. Some keyboards have trouble with that.

[jemkeys]

I'm getting 6 on my HHKBpro2.

It's true that you need a few keys to register at the same time for games.

Call of Duty 4 sometimes requires you to strafe left while moving forward, running, and throwing a grenade .

Well, that's 4 keys.  So I guess my keyboard is enough.

[ecru]

Filco Majestouch Mini FKB100M/NB
Interface: usb or supplied ps/2 adaptor give the same result
Operating System: Debian Lenny - generic 104, mapped to dvorak
2 key rollover - ',ao test (qwas for sholes users)

[jemkeys]

Happy Hacking Keyboard Lite (KB-9975, PD-KB100W)
PS/2
4-key rollover if on same row, 2 key if on different rows.

[Eclairz]

British Clicky (blue stem i checked) Cherry G80-3000LSCGB Fails after 2 key rollover Minimum

QWER works
FTRG works
YUHJ works
QWAS and so does QWEASD fails

So cherry keyboards don't seem to be made for n-key rollover, but my one has vista button (circular indented) instead of normal windows button, so my keyboard might be new set

edit: only tested using usb for now but i dont think ps/2 will be an improvement, i like the keyboard anyway so i'll keep it

[ecru]

Silitek SK9001A-2U (~1991), white alps
Interface: 5 pin DIN replaced with ps/2
Operating System: Mepis 6.5 - dvorak layout
3 key rollover - ',.aoe test, ',ao passes but ',oe fails (qweasd for sholes users)

[ecru]

Cherry G80-3000HQMGB /03 (~1997), white cherry
Interface: ps/2
Operating System: Mepis 6.5 - dvorak layout
2 key rollover - ',ao test (qwas for sholes users)

[Eclairz]

Just got my Steelseries 6G today, well disppointed with the 6G since it is quoted to have 8 key n-keyrollover with ps/2 but testing on usb its minimum workig n-key rollover was only 2
it failed at QAS and WSD which is weird considering its a gaming keyboard. have yet to test it on its native ps/2 so maybe hope for this keyboard yet.

Its much quieter than my blue stem cherry brit keyboard, but i know prefer the noise of the cherry over the steelkeys, and the tactile feeling on the blue stem feels about right whereas the black stem keys just feel like zombies for some odd reason as there is no lessening of pressing power. I heard brown stem has less tactile feel, so at the moment i'd rather have the white-stem cherrys which are blue stem keys without the noise not sure this is correct?

Anyway other than that the 6G comes with taller keys than my blue stem cherry, not too sure i like them this high but maybe i'll get used to them long term. The Steel keys overall look better and have much less flex as well, not that it would effect either keyboard in normal use. But the steelkeys feel better able to be ported with rough treatment between events. blue leds for num lock,etc are very bright and clear which can be a good or a bad thing depending on your taste

edit: oh ye with the spare set of grey keys i can now make a greyscale keyboard with three sets of keys, although the white keys are little shorter (1.5mm about) than the black and grey keys, not sure what i'll do, but most of the keys look interchangeable and with the key tool its much easier to replace the key caps

[djones]

Sorry, I just noticed this sticky. What is n-key rollover and why do I care?

[iMav]

Sorry, I just noticed this sticky. What is n-key rollover and why do I care?

Basically, n-key rollover means that each key is scanned separately by the keyboard's electronics.  Allowing each key to be recognized...regardless of how many other keys may or may not be pressed at the same time.

[bigpook]

I had asked this same question awhile back also. The n rollover seems to be important when playing games.

[Eclairz]

and for people who type at the speed of light (e.g. 100+ words per min)

[bigpook]

That most certainly would not be me.

[zvz]

I had asked this same question awhile back also. The n rollover seems to be important when playing games.

I have an IBM Model M 1391401 made in '89 and I can get anywhere from 4-8 (4 fingers from left hand on qwer, 4 fingers from right hand on asdf) keys on that test, depending on how "in-sync" my right hand is.  Don't really see how it's useful either.   In a couple of tries where I smashed my hands up against my keyboard, I got over 15 once.

I can type over 170 wpm sustained on 3 or 5 minute typing tests w/ 100% acc or at least I could 10 years ago (used to do data entry in high school).  Haven't done any typing tests recently, except going to typeracer.com and filling the high score board up with my name a month or two ago.  Fastest was a little over 200.  =)  So guess it probably hasn't changed so much..

Anyhow, I've never had any problems with my keyboards dropping keys (i've never used anything other than a 1391401 pre-Lexmark and I bought a lot of 5 new "in-box" ones on eBay about 7 or 8 years ago just in case)..... but not really sure how useful this test is..

[iMav]

I have an IBM Model M 1319401 made in '89 and I can get anywhere from 4-8 (4 fingers from left hand on qwer, 4 fingers from right hand on asdf) keys on that test, depending on how "in-sync" my right hand is.

Interesting.  I thought the Model M's failed on this.  Can you throw up a screen shot of "asdfqwer" from the rollover page?  (well, it likely won't be in that order, but you get the idea)

[xsphat]

I've only been able to get the standard 2 with my M.

[zvz]

Interesting.  I thought the Model M's failed on this.  Can you throw up a screen shot of "asdfqwer" from the rollover page?  (well, it likely won't be in that order, but you get the idea)

I decided to do qwerhjkl since it's more natural place for my fingers, not sure if it matters or not if they were on a separate row or what.  Don't really understand the mechanics of this whole n-key thing, so I hope qwerhjkl is OK.  Anyway, I was able to register this successfully 2 out of 5 tries (other times it stopped at qwerhj qwerh qwer, the first 4 never failed).

Here's a screenshot:



I've also been able to type simple words like "help" (<-- ed meant help, not hell), "them", "post", and random stuff like  "posty", "opist", "tykop" w/ 95% success rate.  Words like "this" and "money" are around 50%, but I can type "jist" at 100%.  It seems to be more keen on my typing rate than anything else.  Any words that require 2 of the same letter in a row (like "hello") will always stop at "hel".  So anyhow, not really sure what the whole deal is with n-key rolleover and how it's supposed to work or what.  But that's just my findings w/ my 1391401 (manuf 89 btw).  It seems to me like if I had 20 fingers and a nice big easy to type word, it'd register all 20 keys.

Basically any word where I can use my "2" main fingers from left hand, and 2 "main" fingers from right hand are near 100% success.  Something like "this" that generally requires left hand-right hand-left hand-right hand are a bit harder to register (maybe 40% success rate for me).  Something like "post" where you can use right hand for "po" and left for "st" are simple.  Also words (real or nonsensical) like "posty", "power", "poiwer",  "poker", where the key positions are favorable for fast typing.

Anyhoo, here's another screenshot with a few words and other combos:



ed: and another edit.  my keyboard is connected to a PS2 connector, not a USB port.

and after reading some more posts in this thread and since its 1 am.  i think i'll mess with it some more and just see how many i can get max =)

ok.  I got up to 12 max, in about 5 minutes of random button pushing...  I'm pretty sure I got 15+ once before, but couldnt say for positive.  I kept accidentally hitting alt and such in my random button smashing so it'd mess it up.

interesting enough, i did notice that my 't' key seems to be a bit off.  rtuirtuirtuirtuirtuirtui.... typing rtyui there...but if i type it too fast, the y doesn't show up.  not sure if this is just my specific keyboard, or something "n-key" related on the model M.... if i type 'rtyu' real fast, it shows up as 'rtuy' - rtuyrtuyrtuyrtuy..  interesting enough, tyu works fine.  tyutyutyutyutyutyu.  i'm guessing this might be keyboard specific problem.  maybe i need to dive into my closet and retire this keyboard or maybe needs some cleaning.  if i try to type sdftyu:   sdfuysdfuysdfuy.  but something like, asdyui has no problems:  asdyuiasdyuiasdyui.  so i'm actually a bit curious now.  might try a diff kb.

[xsphat]

My Northgate Omnikey 101 (not 101P) gets 6 all the time, any key combo, any rows mixed. I did qwer asdf and everythign else I know to be hard for 'boards to do. I guess that is subtle proof that these babies are in fact 100% n-key rollover.

[zillidot]

I decided to do qwerhjkl since it's more natural place for my fingers, not sure if it matters or not if they were on a separate row or what.

It does matter since the failure arises from the fact that you have multiple keys pressed on the same column as well as the same row. Since qwerhjkl are all on separate columns, even keyboards which do not have n-key rollover would be able to detect them all.

[iMav]

I decided to do qwerhjkl since it's more natural place for my fingers, not sure if it matters or not if they were on a separate row or what.

Even "qwas" has been documented to fail on the Model M's, so it does matter.  

BTW, welcome to geekhack!

[zvz]

It does matter since the failure arises from the fact that you have multiple keys pressed on the same column as well as the same row. Since qwerhjkl are all on separate columns, even keyboards which do not have n-key rollover would be able to detect them all.

OK, then..

I can type qwera 100% of the time.  'qwerasdf' was more difficult, it did take about 15 tries:



I think it was more luck than anything.  I do notice what ya'll are talking about now in terms of the n-key rollover.  

It wasn't 'qwerasdf' though that convinced me, it was 'qwas'.  That should be easy just like help, dank, anything you can type with 2 fingers from one hand on 2 keys and 2 fingers from another hand on two keys.   QWAS is what I was trying to type, and there wasn't much of an overlap on my hands either.  Can type QWA or QWS, easily... but when I try to do QWAS or QWSA it fails 95% of the time.  Other stuff like QWLK is np.

qwasqwasqwasqwasqwasqwasqwasqwsaqwasqwas... although typing it fast here apparently has no problems..  *scratch*  Something like rtfg, is easy to type.  TYGH (another tyg or tyh moment, with luck involved in getting 4th letter in) is not.  tyghtyghtyghtyghtygh - but no problem typing it here.  Is there some sort of cache involved that's not in that link or something?

Learn something new every day... still can't say it's something I've ever noticed until today though - at least on the keyboards I use at home.  On those cheap $5-$10 keyboards I tend to lose tons of keystrokes and have some stuff inverted, etc.

[zvz]

http://www.renoise.com/indepth/equipment/crippled-chords-without-full-n-key-rollover/     <--- but it erroneously states that IBM Model M keyboards have full n-key rollover, cause now I know at least mine doesnt, maybe some models do

Found that website about it that gave an easier explanation for me to understand (ie keeping x amount of keys pressed + trying to hit a new key = system beep).  Amazing stuff - never knew any of this before.  I guess the 1401 has just '2 key rollover' like xsphat said?  You can only have 2 of these keys depressed at once?   i.e.  If I have QW held down and try to press A, I get a beep.  It says '3 key rollover' is essential for touch typists but I don't see why this is so.  I've never had any problems with it (I guess since it has some sort of key cache that apparently works fairly well and/or maybe because I'm quick to release keys)..   I could see it being a problem in some games where you may have to strafe + move + fire all at the same time.  Probably never noticed it cuz I don't play that type of game (RPG and turn-based strat games for me).   I imagine you could remap the keys though.

Ah well, cool thing to know.  Now I know what to answer if anyone playing some lame FPS game asks me why their system keeps beeping at them.  

[bhtooefr]

Yeah, when you're testing rollover, make sure you're keeping all of the keys held down, not lifting.

And, remember that rollover is expressed in the smallest combo, not the largest - the Model M is 2-key rollover - you can expect any two keys pressed together to work, but no more. Certain combos (sdfjkl) work out to 6, and I suspect there are some combos that do more than that, though.

(I cited sdfjkl as an example, because that one's REQUIRED for brailling, as someone who came on here a while back said. Quick question, does the Customizer 101 support it? Because the 104 family of boards fails - d is blocking k, and l isn't registered while k is being blocked.)

[ecru]

(I cited sdfjkl as an example, because that one's REQUIRED for brailling, as someone who came on here a while back said. Quick question, does the Customizer 101 support it? Because the 104 family of boards fails - d is blocking k, and l isn't registered while k is being blocked.)

No

[bhtooefr]

Verrrrry interesting... wonder if they rewired the matrix for both boards, to support 104 keys, even on the boards that don't have them, so they only have to manufacture one model of membrane for most of their boards?

[alpslover]

anybody else getting weird results with this test using a das keyboard 3?

it seems to be giving results that aren't consistent with real world usage.  i.e., i can get 10 key rollover everywhere else, like here for example:

576nhj8k.l
asd5vgf768
234bv7689[

but if i try this in the rollover test, most commonly it will say 2 key rollover if i'm using 8 fingers, and 4 key rollover if i'm using 10 fingers.  sometimes i'll spuriously get other numbers, but i've never seen it register more than 6.

[alpslover]

i just remembered, there's a supposed 6 simultaneous key limit for usb.  so i limited myself to 6 fingers, and the rollover test now works consistently and correctly, showing 6 key rollover in the rollover test.

if i try 7 fingers, i'll consistently get a value of 1 in the test, which is 7-6.  and this explains the results i get with 8 fingers (registers 2 fairly consistently), and 10 fingers (registers 4).

yet in real world typing usage, i can get 10 key rollover consistently.  metadot claims 12 key rollover, i just haven't tried pressing more than 10 keys at once.

so it seems as if the das keyboard is getting past the 6 key limit of usb with some sort of buffering.  if there are more than 6 keys pressed, the keyboard can't send more than 6 registered keystrokes over usb at a time, so it sends 6 first, then sends the rest.  the rollover test only picks up that second 'bundle' of keystrokes.

how exactly is the rollover test grabbing keyboard input?

[zwmalone]

Datalux Tray Model TORUC
Interface: PS/2
Operating System: Ubuntu Linux 8.04
Max keys accepted: more keys than I can press at once.  (this keyboard supports full n-key rollover)
__________________

[zwmalone]

Even "qwas" has been documented to fail on the Model M's, so it does matter.  

BTW, welcome to geekhack!

My model M 1391401 (1/29/90) doesn't fail on qwas or several other random key combos:confused:

[Astra Diesel]

IBM Model F
-Any combos work, unlimited keys!

[Demi9OD]

Does anyone have any experience with Keytronic or other rubber dome based Keyboards with some n-key rollover capabilities?  I went through a couple of Northgate Omnikey's and Model Ms but kept breaking the space bars.  I hit the very left hand side of the space bar quite often when gaming, and the mechanicals just don't seem as stable across the whole bar, so I am looking for a rubber dome instead.  For the past couple years I used a Logitech Media Elite, which allowed me to press SHIFT+W+A+SPACE+R/F/E with no issues, but it is totally gunked up beyond cleaning.  The cheap PS2 Logitech I picked up as a replacement cannot perform all these keystrokes at once.

[itlnstln]

Maybe the HHKB Lite series would work.  If you like ergonomic boards, the Northgate Evolution (see my avatar) has a split spacebar, so hitting the edge wouldn't be as stressful.  The iOne Scorpius 'board is relatively cheap and mechanical (blue Cherries), but some have had issues with them, and I am not too sure what the rollover is on them.  Personally, I use(d) a Nostromo n52 for gaming.  It's much better than any keyboard for gaming, IMHO.  I use the d-pad on the thumb for UDLR and that leaves my other four fingers free for the other keys, and you don't have to worry about rollover.

[Demi9OD]

I have an n52, but I find the keys far too stiff and it makes moving your hands to type text rather annoying.  I purchased a Keytronics Designer off Newegg, and will update the thread when it arrives.  My roomate has an older Keytronics Lifetime Black PS2 that can press the combinations I need so I thought I would give it a shot.

[Demi9OD]

The PS2 Keytronics designer I purchased can perform...
qwers
qwerz
qwerx
qwerc

but cannot perform
qwera
qwerd

So limited 5 key rollover, luckily the key combos I need work...
SHIFT+A+W+SPACE+R/F/V/C
SHIFT+A+D+SPACE+R/F/V/C

I like the key action and feedback quite a bit

[graywolf]

It occurs to me that I do have an n-key rollover keyboard.

Any and all keys, any combination, not only which key is detected, but also how hard I hit it, and how long I hold it down. It connects via USB to my laptop (it does work with this computer but I usually use it with the Thinkpad). Sounds good to. Only problem is that SP3 broke the software I normally use it with.

It is made by Yamaha, and I have the midi-usb adapter for it. Ta-ta-dahm...

[xsphat]

Topre Realforce 86 connected via USB.

6 keys all day, any combo I try — mixing rows and everything. I got 7 once as well, but it may have been a fluke. I think it's safe to say this baby has full n key rollover, which doesn't surprise me at all.

[Ysaquerai]

Can anybody test the N-Key Rollover of the Apple Pro Keyboard? I might get it from my friend if it has a good key rollover.

[Ysaquerai]

There are reports that Apple Pro Keyboard can have as much as 12 Multiple key press, is this true? At the moment i don't have this keyboard, could anybody validate the N-Key Rollover for this keyboard?

[lam47]

Thread was on 6,666 posts.
Had to do something

Ah balls it was views. I need to sleep.

[cmr]

apple extended keyboard ii
interface: griffin imate ADB to USB adapter
operating system: ubuntu 8.10
minimum keys accepted: 4
maximum keys accepted: 6

[zwmalone]

Chicony KB7001
interface: AT -> AT-PS/2 Adapter -> Belkin Active USB Adapter
operating system: ubuntu 8.10
minimum keys accepted: 3
maximum keys accepted: 6