At OSCON in 2008, Mark Shuttleworth, the founder of Ubuntu and Canonical, challenged the crowd, "The great task in front of us over the next two years is to lift the experience of the Linux desktop. Can we not only emulate, but can we blow right past Apple?"

The challenge was a defining moment for desktop Linux, coming near the start of an era in which KDE, GNOME, and Ubuntu would all attempt to rethink the desktop.

Four years later, speaking again at OSCON, Shuttleworth implied victory. "We've leapt ahead of some of the competition," he said, claiming that Ubuntu's Unity desktop was now the second easiest to use after Windows, and showing specific elements in which he felt Unity surpassed Mac OS X.

The announcement of victory was quieter than the challenge -- unsurprisingly, perhaps, considering that it came in four years, not the promised two. However, design considerations, their receptions within Ubuntu, and Ubuntu's interactions with other projects concerned with desktop Linux all forced delays that he could not have foreseen in setting the challenge.

Nor, originally, had Shuttleworth specified that the challenge was to develop an interface as equally suitable for a workstation as a mobile device, although a few months later, he was thinking in those terms.

Most of all, the challenge was addressed to free software in general -- or was widely interpreted that way. In the context of the times, the challenge appeared another of Shuttleworth's efforts to reform how projects cooperated.

However, the community proved largely unwilling to place itself under his direction, and in practice Shuttleworth and Ubuntu committed themselves to improving usability in isolation.

Still, even under these revised terms, the question remains: Is Shuttleworth's claim of victory plausible?

To find an answer, I compared the version of Unity in the current release of Ubuntu 12.04, with OS X 10.6.8 -- not the latest version, which came out shortly after Shuttleworth spoke, nor even the next to current version, but one that remains widely in use and therefore seems a fair basis of comparison.

The answer, I quickly found, was far less straightforward than I expected. For one thing, the major differences are confined to two main sets of feature -- the launcher or dash and the menu replacements. For another, how you answer is likely to depend strongly upon your assumptions about what a desktop should do.

Internal Logics

At first, Shuttleworth's claim seems unlikely. No doubt Ubuntu's design team can cite reasons for each of its decisions, but the only people who haven't observed Unity's similarity to OS X must be those who have never glimpsed a Mac.

It is not just that Ubuntu's default Ambiance theme uses a gradient wallpaper with a family resemblance to OS X's popular Aqua theme. Rather, the family resemblance extends across the desktop.

Functions are positioned according to slightly different logic, but the positioning of major features is similar in both OS X and Unity, down to the positioning of title bar buttons to the top left of the window.

This similarity is especially noticeable in the panel. In both Unity and OS X, the left side of the panel is reserved for the menus of the current application. Here, Unity's major claim to improvements is the fact that it conceals the menu until the mouse passes over it, producing a less cluttered look for someone looking at the desktop.

On the right are the traditional indicators for Internet connections, battery status, chat availability and the current account. Neither Unity nor OS X allows users to customize the panel with widgets as KDE or GNOME 2 do, but OS X uses indicators far more freely than Unity.

Unity, in comparison, can boast of having the ability to embed a particular application in an indicator for over a year – something that OS X only gained in the latest release.

This similarity with minor variation is an immediate challenge to Shuttleworth's claim. With so much similarity, how convincing can any claim to superiority possibly be? Even improvements are diminished by the fact that, without the original, the improvements would hardly be possible in the first place.

Launcher vs. Dash

One of the main places where strong differences appear is Unity's launcher and OS X's dash (not to be confused with Unity's menu replacement of the same name, although it almost certainly will be).

OS X's dash has far more in common with Linux's Avant Window Navigator than with Unity's launcher. The OS X dash is highly configurable, with its position on the screen and the size of its icons all adjustable. A right click opens a context menu of possible actions.