Desktop Virtualization and Operating Systems

So what's the answer to all this operating system and hardware driver angst?

I'm going to make the argument that the answer, insofar as there is one is probably virtualization.

But wait, tycho, this virtualization stuff all about servers. Right?

Heretofore, virtualization technology--the stuff that lets us take a single very powerful piece of hardware, and run multiple instances of an operating system that, in most ways "think of themselves" as being an actual physical computer--has been used in the server way, as a way of "consolidating" and utilizing the potential of given hardware. This is largely because hardware has become so powerful that it's hard to write software that really leverages this effectively, and there are some other benefits that make managing physical servers "virtually" a generally good thing, and there aren't a lot of people who would be skeptical of this assertion I think.

But on desktops? On servers where users access the computer over a network connection, it makes sense to put a number of "logical machines" on a physical machine. On a desktop machine this doesn't make a lot of sense, after all, we generally interact with the physicality of the machine; so having multiple, concurrently running, operating systems on your desk (or in your lap!) doesn't seem to provide a great benefit. I'd suggest the following two possibilities:

  • Hypervisors (i.e. the technology that talks to the hardware and the operating system instances running on the hardware,) abstract away the driver problem. The hypervisors real job is to talk to the actual hardware, and provide a hardware-like-interface to the "guest operating systems." Turns out this technology is 80-90% of where it needs to be for desktop usage. This makes the driver problem a little easier to solve.
  • Application specific operating systems. One of the problems with desktop usability in recent years is that we've been building interfaces that have needed to do everything, as people use computers for everything. This makes operating systems and stacks difficult to design and support, and there is all sorts of unforeseen interactions between all of the different things that we do, which doesn't help things. So desktop virtualization might allow us to develop very slim operating systems that are exceedingly reliable and portable, but also very limited in what they can accomplish. Which is ok, because we could have any number of them on a given computer.

I only need one instance of an operating system on my computer, why do you want me to have more?

See above for a couple of "ways desktop hypervisors may promote the growth of technology." But there are a number of other features that desktop virtualization would convey to users, but it mostly boils down to "Easier management and backup."

If the "machine" is running in a container on top of a hypervisor, its relatively easy to move it to a different machine (the worst thing that could happen is the virtual machine would have to be rebooted, and even then, not always.) It's easy to snapshot known working states. It's easy to redeploy a base image of an operating system in moments. These are all things that are, when we live "on the metal," quite difficult at the moment.

For the record, I don't think anyone is ever really going have more than five (or so) instances running on their machine, but it seems like there's a lot of room for some useful applications around five machines.

And lets face it, TCP/IPA is the mode of inter-process communication these days, so I don't think application architectures would likely change all that much.

Won't desktop hypervisors have the same sorts of problems that "conventional operating systems," have today. You're just moving the problem around.

If you're talking about the drivers problem discussed earlier, then in a manner of speaking, yes. Hypervisors would need to be able to support all kinds of hardware that (in many cases) they don't already support. The argument for "giving this" to hypervisor developers is that largely, they're already working very closely with the "metal" (a great deal of hardware today has some support for virtualization baked in,) and hypervisors are in total much simpler projects.

Its true that I'm mostly suggesting that we move things around a bit, and that isn't something that's guaranteed to fix a specific problem, but I think there's some benefit in rearranging our efforts in this space. As it were

Don't some of the leading hypervisors, like KVM and others, use the parts or all of the Linux Kernel, so wouldn't this just recreate all of the problems of contemporary Linux anew?

I'll confess that I'm a huge fan of the Xen hypervisor which takes a much more "thin" approach to the hypervisor problem, because I'm worried about this very problem. And I think Xen is more parsimonious. KVM might be able to offer some slight edge in some contexts in the next few years, like the ability to more intelligently operate inside of the guest operating system, but that's a ways down the road and subject to the same problems that Linux has today.

So there you have it. Thoughts?

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