OT: Hackintosh

Yeah, this seems to be a more effective way of approaching the problem (feasability). The other sites I've seen seem to be more along the line of "I got it to work on a __________". Far too many potential "___________" for me to hope for a "hit"!

The video on my Atom SBC is, AFAICT, SiS-based. So, no joy there.

I've received another offer from another (out-of-state) friend. But, that gets more tedious to exploit (shipping, risk of damage in transit, etc.)

I can also put this on my list of things to watch for at the various "surplus" outlets that I frequent: borrow one and return it... no "loss" there!

I dispute that. PC keyboards report key down and key up to the mainboard for all keys. That intrinsically gives them n-key rollover. Whether or not it is processed that way is another matter, that is not done on the keyboard.

?-)

(snip)

That means that they have the ability to report such keys, not that they actually do it.

The do have to report shift, control, alt, and such, in addition to other keys that are pressed while some combination of those is down.

To do a proper N-key rollover, you need a diode in series with each key switch. Without the diodes, you can get a large combination of more than 2 keys, but not all of them.

-- glen

Indeed. For a matrix keyboard relying on electrical contact, the lack of diodes leads to 2-KRO. Optimized layouts, like placing modifiers on carefully selected rows/columns, might somewhat hide this.

Heck, even the classic IBM M keyboards, being membrane, are 2-KRO.

Joseph, if you're still unsure, just try pressing various combinations. Or open the thing.

No, Model-Ms are not membrane keyboards. They are "buckling spring".

And the buckling spring moves a pivot (hammer), which presses on ... membranes.

Well I will be dipped...

Sure enough, most are not, but they've done a pretty good job of hiding that from most users.

Here's a test I came across that seems to work well. Hold down both shift keys, then type "the quick brown fox jumped over the lazy dog". The results were surprising on pretty much every keyboard I tried.

OTOH doing something like typing and holding down asdf, then pressing

7878... works fine on all they keyboards I tried. There are clearly several separate scan matrices, enough so that I'm wondering how much they actually saved over doing real n-key.

Sure a camera, ignoring the visibility problems, would work, but most simple touch devices are more along the lines of sensing a resistance or capacitance caused by your finger one the two axis. Or they do a simply number of rows and columns "sensors", where your touch causes a connect (again, not unlike a scanable keyboard matrix). None of those lend themselves to multi-touch.

mainboard

or

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Or

Guys, to report what is being reported to the mainboard n-key rollover in its full glory is necessary. It has little or nothing to do with some lower level circuit or switch properties. Think it through.

?-)