TrackBalls are almost a thing of the past, making very few appearances on a modern desktop PC and mainly seen in those poorly built internet kiosks at airports. Just like the IBM ThinkPad's nipple style controller, there are a few die hard fans out there that live by trackballs.
The principle is very similar to the old style ball mice, those unreliable things that were welcomed with replacement by modern optical mice. The old mice run a ball across the surface of the desk and rollers detected movement. Flip the mouse upside down, make the ball larger and you pretty much have a track ball.
The SlimBlade TrackBall from Kensington has certainly made some improvements on the original design. To start with it uses optical tracking, so you don't have problems with a dirty ball, or sticking, catching, rollers. It floats on three very small beads that provide an almost frictionless experience. The ball is highly polished, with a red metallic finish. Not only visually appealing, this makes for great tracking accuracy.
We'd struggle if we were given a computer without a scroll wheel, or track pad with a scroll zone. Thankfully, Kensington has thought of this. Whereas moving the wheel forwards or backwards will move the cursor around, twisting the ball - like you would a volume dial - scrolls up or down. This works really well with a reassuring click that isn't too obtrusive.
One thing you very quickly notice when compared to a mouse, is how accurate you can be. The smallest of movements can be picked up, which is great for image editing. The scroll wheel is also very easy to get an accurate, single click for moving single lines at a time.
The ball is housed in a solid platform that is about the size of a CD case. The whole surface makes up four individual buttons. The bottom two are the traditional left and right mouse clicks. They are fairly sizeable, so you can pretty much click anywhere in that quadrant and you'll get a result.
Up to this point, everything is done in a standards compliant, hardware mode – so Linux, Mac and Windows is fully supported. However, to gain anything from the extra two buttons at the top, you'll need the drivers installed, which are available for Mac and Windows.
The top left button puts the SlimBlade into “Media Mode”. In this mode, scrolling (spinning) changes the volume, moving left or right changes the track and the buttons control playback. Clicking the button again and the track ball returns to normal use. This is designed to work with iTunes and Windows Media Player, so if you use anything else, you're out of luck.
The top right button puts the SlimBlade into “Document View” mode. Here, a scroll zooms in and out, moving the ball moves the document around on screen and the buttons control various display options. This is apparently not supported in all applications either.
Considering that these functions don't work in every application and you won't find them on any other computer, it's not something you want to find yourself too dependent on. Making these buttons the back/forward buttons that are generically recognised by web browsers would have been much more useful and would have removed the need for any drivers at all.
We don't think you'd want to use this for gaming and you certainly wouldn't want to carry it around in a laptop bag as the ball is not attached. The plus side to this is that keeping it clean is very easy – especially if you have John Virgo at your disposal.
The Kensington SlimBlade TrackBall is a really nicely made piece of kit but comes at a hefty price tag of nearly £100. If you've never tried a track ball and struggle with a normal mouse, they are worth a shot – but at £100, it's not something you are going to try on a whim.