You'll recognize the picture above if you're a Mac user of a certain vintage (does secret Vintage Mac User handshake), but anyone who came to Apple this century is probably looking at it with more questions than answers. Is it broken? What is with that space bar? And, possibly, oh my gosh, were Macs really ever that beige?

It's a keyboard of course; the Apple Adjustable Keyboard. And it doesn't have to look quite so alarming. It's hinged at the top so you can if you like have it completely straight:

...or pull it apart so it's angled. Why? Ergonomics. Formal touch typists--by which I mean typists for whom typing is the major focus of their job, not typists who wear pinstripes and address people by their surnames--were taught that the correct way to type was to always have their fingers resting lightly on the "home keys," keeping the hands still and stretching and curling the fingers to reach the other keys. That's why to this day keyboards have little nodules on F and J (though on Apple's early keyboards such as this one, the bumps are on D and K), so you can feel for them. Rest your left hand's index finger on F, your middle finger on D, ring finger on S and pinkie on A, then mirror this on J, K, L and semicolon.

So few of us type "properly" these days that you might never have done this before, and you'll notice that while your arms stretch towards the keyboard at about 45 degrees, your hands have to splay outwards uncomfortably. This can lead to some terrible carpal tunnel syndrome, severely damaging your hands. Ergonomic keyboards, then, attempt to solve this by allowing you to rest your fingers on the home keys while keeping your wrists straight:

Frankly, I'm too broken to use it like that. I'm a fast typist, especially on the current low-rise, chiclet Apple keyboards, but I keep my wrists straight, move my hands all over the keyboard, and only really type with my two index and middle fingers plus my right thumb for the space bar. I did try to write this with the keyboard in split mode but I had a deadline to hit and a few tattered vestiges of sanity to cherish.

It had some other ergonomic features too. Although I don't have them for my keyboard, it originally came with huge, wide paddles that attached at the front and provided a surface on which you could rest your wrists. What's more, the numberpad and function keys are on an entirely separate unit, and that's actually a huge ergonomic boom. If, like me, you're right-handed and use a standard wired Apple Aluminum Keyboard, you might never have noticed that you actually have to stretch your arm quite far to use your mouse; by slicing that numberpad off on the right, you can have your mouse much closer, meaning less strain. (Apple did used to make compact versions of its wired aluminum keyboard, which I'd prefer, but I struggle to find one in UK layout even on eBay.)

You could raise the Adjustable Keyboard on some feet at the back, although that too causes you to flex your wrists so isn't recommended.

Although I didn't use it split, I did write this using the Adjustable Keyboard, on my MacBook Pro running Yosemite. And even though it uses an old connection which Apple hasn't used since the blue and white Power Mac G3, it's really easy to connect up old keyboards like this one or the legendary Apple Extended Keyboard that the modern Matias Tactile Pro is designed in homage to.

Griffin Technology used to make an adapter called the iMate which would convert ADB keyboards to USB, and though the company politely and with some bemusement declined to send me one of these long-discontinued widgets, they're readily available on eBay.

Using it (for a standard piece of equipment like a keyboard) couldn't be easier. You just plug the ADB keyboard into one end and then plug it into a USB port on your Mac. The multimedia keys on this Adjustable Keyboard don't work, but everything else does, including the power key for bringing up the shutdown dialog. (You can replicate this on modern Macs by holding down Control and Eject.)

If you can't find an iMate or you fancy a bit of a challenge, you could always make your own adapter.

Even though I love this keyboard's quirkiness, and I think today not enough thought is given to ergonomics, as soon as I'm done here I'm going back to my Aluminum Keyboard. Pressing the keys on the Adjustable Keyboard feels like when you impersonate a T. Rex and take slow, exaggeratedly big steps. I don't type as fast and I make frequent mistakes, whereas on my Aluminum Keyboard, my fingers scurry across the keys like the evolutionarily favored shrews under the T. Rex's feet.

Still, it's undeniably charming, in a way that my Aluminum Keyboard isn't. Maybe I won't disconnect it just yet...

What was your favorite Apple keyboard? Do you still use it today? (Or do you think you might, now you know how easy it is to keep ADB keyboards in service?) Share your memories in the comments below!