Back in July 2009, I wrote about the upcoming Type 1 bare-metal client hypervisor and how it compared to the more tried-and-true Type 2 hypervisor. As a quick refresher, a Type 1 hypervisor is the operating system and installed on the client natively, while a Type 2 hypervisor is like an application that runs on top of the base OS -- Windows, Mac, Linux, etc. Both types of hypervisors let users run one or more virtual machines locally on their laptops or desktops.
For the past year or so, I felt that while Type 2 were more common, the better client virtual machine (VM) solution would be when the "real" Type 1 hypervisors came out. I thought, "With Type 2, you have to deal with the local native OS and the hypervisor and the guest virtual machine -- that's a lot of work!" I felt that Type 1 would be a simpler, better performing, more solid solution.
Fast forward to today. Now we have Type 1 client hypervisors and Type 1-like solutions from many vendors, including Citrix, MokaFive, Virtual Bridges and Virtual Computer. I've played with all of these products recently, and you know what? Type 2 hypervisors aren't all that bad.
The main drawback with Type 1 hypervisors is that because they "take over" the laptop by replacing the native OS with the hypervisor, you need a really big commitment to get them working properly. You have to collect and re-image your machines and then get your desktops running VMs. In some cases, like with Citrix XenClient, the list of supported machines is very small -- only 23 different laptop models so far. All of these machines are newer models, so your existing machines most likely won't work.
But the biggest pain with client hypervisors is that since you're taking over the laptop, they represent a big "commitment" to the hypervisor and desktop virtualization. Even though you don't have to deploy your client hypervisor to all of your users, the ones that do get it are 100% virtual. Period.
Compare that with Type 2 hypervisor-based client environments, such as those from MokaFive, RingCube, Virtual Bridges and VMware. Since Type 2 hypervisors install just like a regular desktop app, you have a virtually unlimited supply of desktops and laptops that are compatible. "Does the laptop run Windows? Yes? OK, you're in!"
And since Type 2 hypervisors don't replace the local OS, you can install them just as easily as any application. Deployment is simple, and users can seamlessly switch between applications from their local VM and their native local OS. This means that you can "dabble" in desktop virtualization and slowly deploy client VMs without too much effort.
Client hypervisors are a great way to deliver desktops, whether they're Type 1 or Type 2. Sure, Type 1 hypervisors may be more secure or offer better VM performance, but that doesn't mean that there's no place for Type 2. Type 2 hypervisors will be around for a long time because they can be installed quickly and easily on a wide range of hardware, and there's no shame basing a deployment on Type 2 today.
ABOUT THE AUTHOR
Brian Madden is an independent industry analyst and blogger, known throughout the world as an opinionated, supertechnical desktop virtualization expert. He has written several books and more than 1,000 articles about desktop and application virtualization. Madden's blog, BrianMadden.com, receives millions of visitors per year and is a leading source for conversation, debate and discourse about the application and desktop virtualization industry. He is also the creator of BriForum, the premier independent application delivery technical conference.
This was first published in November 2010