News on the upcoming Windows Virtualization OS: Codename Viridian

by David Davis on May 24, 2007

Well, just like those entertainment news shows on TV have celebrity gossip – us “techie” people have our celebrity gossip. Here is the latest-

News on the upcoming Windows Virtualization OS: Codename Viridian

(yes, just like those shows, maybe this shouldn’t be called news but, gossip)

(and no, I’m not leaking anything confidential here as this has been posted on many other websites and was discussed with Microsoft people in the room at a public seminar)

Microsoft will have a higher end virtualization solution that will take on VMware ESX – head to head

This next OS is currently codename – Veridian and it will be released along with the Longhorn Server OS (now dubbed “Windows 2008”)


The features required to compete with ESX will come in a variety of releases so the first release won’t have all the features. Some of these features that won’t be available are “hot add” for the hardware and “live migration” (similar to VMotion).

Viridianwill offer a thin “host OS” & virtualization layer (like VMware’s VMKernel & Service console). So this “Service Console” will be Windows Core Server (no GUI). This thin virtualization layer will provide much better performance. Here are some rumored specs:

– 64 bit hardware will be required

you can have 32 bit & 64 bit child partitions

large memory support (> 32GB) within virtual machines

– SMP 2/4/8 way VM

– “raw” disk access options

– hot backup of VMs using volume shadow

in the future – live migration, “hot add” of hardware, and up to 64 processors on a Virtual Host


One of the big features Microsoft will tout over VMware ESX is the ability to install 3rd party sw drivers inside windows server core on the parent partition. This is something that VMware ESX cannot do. However, what I am thinking is, maybe you don’t want to do this anyway because of potential stability issues caused by 3rd party drivers.

The parent partition and guest OS’s communicate on something called the VMBus. This VMBus feature is available only to supported Guests. Those supported guests will be Windows, Novell Suse Linux, and VMs from Zen.

So here is my short list of benefits of using Veridian over VMware ESX:

Microkernel hypervisor – window server core

Drivers run within guests

Drivers must be installed inside parent partition but are available much faster because you can just install the drivers inside the parent partition and child can use that driver and access that hardware, through the VMBus

Supports more processors that ESX, ESX only 4

Memory – > 32GB, ESX only 16GB

Hot add cpu, memory, and networking


I’m not telling anyone to drop VMware ESX and move to Microsoft – only hoping to provide the rumored differences between Microsoft’s new product and ESX. I use VMware ESX myself and it is an amazing product. Microsoft has an uphill battle in trying to unseat ESX from the top spot. However, Microsoft had some proven experience in doing that – remember that thing called “Netscape” that used to be the #1 web browser?

Questions or comments? Post em‘ here!

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