Originally Posted by larymoencurly
I'm confused. How can ghosting happen with just 2 keys? Because whether the 2 keys are in the same row or column or in different rows and columns, it would seem that the decoder will always distinguish both keys properly. OTOH if 2 keys are held down, a 3rd key pressed in the the same rows or columns could be impossible to distinguish, unless each key had a diode in series with it.
It's wierd that the IBM Model M doesn't have n-key rollover but the older 84-key Model F does.
That's not ghosting. This is ghosting:
- You press 2 keys at the same time.
- Out of nowhere, a 3rd key is activated even though you physically did not touch it.
So, you physically did not touch that 3rd key, but its signal was sent anyway. How does this happen? Ghosting. It's an old problem that we no longer have to deal with. So ghosting has absolutely nothing with how many keys you can press simultaneously without having some of them get blocked. That's key rollover.
So, FranBunnyFFXII is referring to key rollover where the Left Arrow key is not registered when either F+G are pressed at the same time first, or F+V are pressed at the same time first. This is a key rollover issue, not a ghosting issue. A ghosting issue would be like, you press F+G or F+V and some other random key's signal is sent exactly as though you physically pressed it even though you didn't.