What are 'zero clients,' and how are they different from thin clients?

At Citrix Synergy 2010, Wyse unveiled the Wyse Xenith, a "zero client" device. Find out how this stateless technology works and how can help with device management.

At Citrix Synergy in San Francisco last week, Wyse unveiled a new product called Wyse Xenith, which is based on the newly announced Wyse Zero platform. Similar to a thin client, the Wyse Xenith is being marketed as a "zero client." Let's look at the differences between a thin client vs. zero client, what exactly a so-called zero client is, how it works and why you'd choose one over a more traditional thin client.

The term thin client means different things to different people. We took a deeper look at the various types of thin clients earlier this year, but the one thing they have in common is that they offload most (if not all) of the heavy work to back-end servers, resulting in a client device that is small, light and, most importantly, stateless.

It's that "stateless" attribute that's the center of attention today. Even though thin clients don't do anything without a network or some servers, some software is often still installed and maintained on the thin client itself. Usually taking the form of firmware or installed into flash memory, thin-client devices typically run an operating system such as Windows CE, Windows XP Embedded or Linux.

So what's the big deal? Even though these thin clients run an OS, they're stateless, right? Doesn't that mean there's no management? Unfortunately, that's not always the case.

First of all, thin clients running any OS might need to be patched or updated from time to time. Even though this patching isn't as frequent as the "Patch Tuesdays" we're all accustomed to in the Windows world, there's often a need to update a thin client's software to deliver new features or capabilities. Second, thin clients often need to be managed to deploy new configuration options or settings.

Thin client vs. zero client

So even though thin clients don't have any real data on them and do most of the work via central servers, they can still be a pain to manage. To solve this problem, a few vendors starting selling what they called "zero clients" -- client devices with literally no configuration and nothing stored on them. From a functional standpoint, zero clients and thin clients are pretty similar, it's just that zero clients have zero device-based management.

The technology has been around for years, but it wasn't until VMware partnered with Teradici to bring the PC-over-IP (PCoIP) remoting protocol to the VMware View product that zero clients really caught on. (Thin-client makers can create zero client devices for VMware View, and VMware had much success selling these against Citrix.)

Wyse's Xenith product is a zero client that's specifically built for Citrix XenDesktop environments and fully supports Citrix's ICA/HDX protocol stack. The Xenith has no OS and no firmware; instead, it connects to a XenDesktop configuration server to download its configuration and the latest HDX engine as soon as it's powered on. (This process only takes a few seconds.) This means that the entire client environment is managed and configured on the server, and there's nothing to update on the client, since the client updates itself automatically whenever it's turned on.

Even though zero clients have been around for a while, you can bet that now that Citrix has joined the zero-client fray -- Wyse already joined since it also makes VMware View-based PCoIP zero clients -- this space will heat up over the next few years.

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.

Dig Deeper on Virtual desktop infrastructure and architecture