As the Wayland FAQ states, "It's a minimal server that lets clients communicate GEM (Graphics Execution Manager) buffers and information about updates to those buffers to a compositor. To do this, it uses OpenGL, a high-performance, cross-language, cross-platform graphics applications programming interface (API)."
What about drivers? Again, we turn to the Wayland FAQ: "Where possible Wayland reuses existing drivers and infrastructure. One of the reasons this project is feasible at all, is that I'm reusing the DRI drivers, the kernel side GEM scheduler and kernel mode setting. Wayland doesn't have to compete with other projects for drivers and driver writers, it lives within the X.org, mesa and drm community and benefits from all the hardware enablement and driver development happening there."
You won't need to give up X-based applications though to use Wayland. Shuttleworth is "confident" that Ubuntu will "retain the ability to run X applications in a compatibility mode, so this is not a transition that needs to reset the world of desktop free software. Nor is it a transition everyone needs to make at the same time: for the same reason we'll keep investing in the 2D experience on Ubuntu despite also believing that Unity, with all its GL dependencies, is the best interface for the desktop. We'll help GNOME and KDE with the transition, there's no reason for them not to be there on day one either."
Unity on Wayland isn't going to come quickly though. Shuttleworth wrote, "I'm sure we could deliver *something* in six months, but I think a year is more realistic for the first images that will be widely useful in our community. I'd love to be proven conservative on that, but I suspect it's more likely to err the other way. It might take four or more years to really move the ecosystem. Progress on Wayland itself is sufficient for me to be confident that no other initiative could outrun it, especially if we deliver things like Unity and uTouch with it."
In other words, Wayland will be an option, and one that only people who don't mind having their desktops blow up on a regular basis should fool with, in Ubuntu 11.04. By Ubuntu 11.10, it will be workable, and come the spring release two years from now, Ubuntu 12.04, we should, if all goes well, see a stable Wayland-based Unity desktop.
Unity and users
Unity first came out as the default desktop for Ubuntu 10.10 Netbook Edition. To make it work on the desktop instead of on the netbook, where one foreground activity at a time is the rule, Shuttleworth admitted that Ubuntu had "a lot of work to do around windows management."
For now though you can use the Netbook Edition to get an idea of Unity's look and feel. One thing you can't do, however, is use it in a VM (Virtual Machine). At this time, Unity won't work in VMs like Oracle's VirtualBox. You'll get a driver not found message and end up with the usual Ubuntu 10.10 Gnome desktop -- not that's there anything wrong with that!
To get to Unity, you'll need to run it on native hardware. If you don't have a spare PC around though you can still try Unity as it exists now without installing Ubuntu Netbook Edition by using a live USB stick.
For my tests, I did both. I installed it on a Dell Mini 9 with its Intel Atom 270 Diamondville CPU running at 1.6GHz. The one I used came with a gigabyte of RAM and an 8GB SSD (solid state drive). The display is not quite nine-inches -- 8.9-inches with the graphics pushed by the Diamondville's built-in 945GSE graphics. The default resolution is 1,024x600.
I also ran it from a USB drive on a Lenovo R61 ThinkPad. This older laptop uses a 2.2GHz Intel Core 2 Duo processor T7500 and has 2GBs of RAM. As you would expect, it ran faster (once it loaded) on the ThinkPad, but it was still usable on the Mini 9 netbook.