The QWERTY layout of the standard keyboard was designed to avoid the keys of a typewriter tangling when you type quickly.
Computer keyboards have a similar problem; they stop you hitting too many keys at once because the keyboard can't cope with that many inputs.
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That's helpful if you hit more keys thank you meant to in the middle of typing a word and less helpful if you're trying to use key combinations at speed in a game (or in Photoshop). The problem is called N-key rollover or anti-ghosting (because the keyboard matrix is designed to prevent 'ghost' key presses).
Microsoft's new SideWinder X4 gaming keyboard takes a different approach; you can press as many keys as you want at the same time (up to 26, to make sure that whatever key combination you want will work).
"Game software doesn't limit you from pressing two, three, four or five keys at the same time," says Microsoft Product Manager Bill Jukes, "but the hardware does. Think of this as 'what you press is what you get'."
We got a chance to try the keyboard out – and to take it apart to see how it works.
The matrix that connects the keys inside most keyboards has a single sensor for each key, laid out in a grid with a crazy pattern of connections between them.
SIMPLER MATRIX: The matrix of a conventional keyboard (left) has a far more complex layout than the SideWinder X4 (right)
"The normal matrix grid should look nicely ordered - it should look like a grid," explained Steven Bathiche, the research manager of the Applied Sciences Group who came up with the multi-touch system in the SideWinder X4.
"It obviously doesn't. The reason is that a 'ghost' hit happened here, here and here…Keyboard manufacturers spend a lot of effort moving ghosts around; they have a list of typical keyboard combinations people press and they try to minimise the ghost hits."
INSIDEWINDER: We took the SideWinder X4 apart, peeling back the protective layer over the keyboard matrix
The SideWinder x4 looks much neater inside; it has strips of resistive multi-touch digitiser underneath each key, with much simpler connections running between them.
Bathiche gives much of the credit to Paul Dietz, the ex-Disney imagineer who came to the Applied Science Group after designing the Mitsubishi DiamondTouch, one of the first multi-touch capacitive tables; "we've had this problem for around two decades and he was able to take this technology from a different field and his team came up with this technology in about a month".
The multi-touch sensors mean you can press as many keys as you want at the same time – and the simpler, shorter connections means the keyboard can read the signal from each key faster.
FULLY FEATURED: Media keys and three banks of programmable keys mean you hardly ever need to let go of the SideWinder
Even though the keyboard isn't scanning for key presses all the time the way most keyboards do (to reduce the amount of power it uses), Bathiche says "as soon as any key is pressed we'll start to scan, we scan all the keys at the same time and you go from a typical 8 millisecond latency to 2 milliseconds – in gaming that really gives you an edge".
Previous multi-touch keyboards have been very expensive; "we figured out how to print thin-film resistors, says Bathiche, "but the big innovation was that we figured out how to make it really cheap."
The $59.99 price tag is certainly lower than many other gaming keyboards and anti-ghosting isn't the only feature. You can switch the backlight from full to 75 or 50% brightness if you're playing late at night or turn it off altogether.
LIT UP: The backlighting shows the multi-touch strips behind each key (two strips are cheaper than one larger piece)
There's a set of media keys and you can create macros (or record them from a game) and assign them to the 18 programmable keys; you can have different sets of macros for different profiles, and the keyboard will load profiles automatically when you start a game you've created a profile for. A switch moves you from normal typing mode to gaming mode (disabling the Windows key, for example).
The SideWinder X4 isn't just for gamers and advanced Photoshop jockeys; Bathiche mentions a music app that turns the keyboard into – well, a keyboard, and says the technology (which Microsoft will licence to other manufacturers) could also make for more accurate typing on small keyboards on netbooks by detecting which of several keys pressed at the same time you actually meant to hit. "It's applicable to many different devices; mobile phones, anything that has buttons…"