Currently, you create virtual machines (VMs) using standard operating system (OS) installation media. You use the same Windows DVDs, Linux CDs and DVDs or ISO files for installing VMs that you do for installing physical systems. Sure, a VM can do almost anything a physical system can do but shouldn't we have the option of using a fully-optimized virtual machine OS? An operating system specially formulated to play well on a hypervisor. Be it Windows, Linux, Solaris, Mac OS or some other ill-conceived lump of bits and bytes, a true virtual machine OS is what we want.
Who'll step up to the challenge of delivering the first virtual machine operating system?
It might be years before anyone accepts the gauntlet so I've decided to help out a bit with my own vision of the first virtual operating systems.
Microsoft's Entry: Windows Virtual 2012
Windows Virtual is a standard, stripped-down version of Windows. Think Windows Server 2008 Core but with the graphical interface. The size of a full installation is a mere 5GB/8GB (Server/Desktop) because it has a limited set of drivers, optimized generic graphics, and hooks into all of the major hypervisors. It has an incredibly fast 128-bit journaling filesystem, low memory footprint, and optimizations for multiple vCPUs. It knows on which hypervisor you've installed it and has made the appropriate adjustments.
Windows Virtual is truly a thing of beauty. It's able to participate in domains or as a standalone system. It's a fully-enabled TCP/IP system and the ever-chatty NETBIOS protocol is nowhere in sight.
It arrives equipped for interoperability by default with a full suite of TCP/IP utilities and an optional SSH server. The system also comes standard with unlimited remote terminal services client connections. Microsoft enables this feature in their server and their desktop versions to take full advantage of VDI possibilities with the highest imaginable VM density.
Windows Virtual also arrives with dynamically expanding virtual disks--yes, even the system disk can be dynamically expanded or contracted. And, the best feature of all? Reboots only occur after a major service pack update that involves the kernel. Microsoft has finally figured out how to make their dynamic loading libraries load dynamically.
Another major improvement is that all processing occurs in the background. The only foreground processing is done during an interactive user session. Windows Virtual also sports a volatile, memory-bound pagefile that efficiently and routinely purges itself without reboots or crashes.
Linux Community Entry: Linux Virtual OS 1.0
Sure, Linux already has many of the features described in my science fiction version of Windows above but there's still room for improvement. Canonical will most likely cross the finish line first in the Linux Virtual OS race, bringing us the easiest and most secure version of the Linux virtual operating system.
Standard fare for the Linux Virtual OS are dynamically expanding disks, remote desktop services so that users can use universal clients to connect to Linux and Windows systems. Of course, they'll come standard with an SSH server and a fast, journaling filesystem. The Linux Virtual OS will be fully hypervisor aware, ship with a limited set of hardware drivers and support all of the major hypervisors.
A server installation should install in less than 2GB of space and a desktop system in less than 5GB.
Yes, there's less to say about Linux as a virtual machine OS because it has a shorter path to virtual machine perfection than Windows does.
Apple: Mac Virtual OS XII
Apple has much to gain by allowing its hallowed OS into the virtual realm. Think of all the Mac addicts that would love to use Mac virtual machines with their iPhones and iPads. As smart as such a thing sounds, unfortunately Apple will continue its shortsightedness in this area. Mac Servers and Mac Desktops will likely find space in virtual infrastructures when Cupertino freezes over. It's a nice thought though since everyone could benefit from Mac VDI.
Thus far, only OpenSUSE Linux has made strides toward a virtual-aware OS by including VMware Tools by default. I'm hopeful that their vision will filter into the other distributions in the next year or so.