The problem some users find with thin clients is that vendors keep adding capabilities to the hardware, making them smarter but harder to manage -- which defeats the entire purpose of using thin clients in place of traditional desktop PCs.
In fact, it is very easy to fall into the trap of turning thin clients into thick clients, said Tim Ragland, CIO and director of management information services at the Mississippi State Department of Health. The agency has 2,600 employees who use Wyse thin clients.
"Users want all the bells and whistles of the PCs they are used to, but we don't want them storing a lot of stuff on hardware drives and turning their thin clients into PCs," Ragland said during a recent interview. "The whole point of a thin client is to have them store on the server, where we can manage everything."
"Zero" clients erase that problem, because they have almost no software or memory for end users to access, and nothing for IT pros to manage.
The "almost" part is important to note, because vendors market zero-client devices as having no software or memory, which isn't the case, said Mark Margevicius, a client computing analyst at Stamford, Conn-based consultancy Gartner Inc.
"All of the vendors -- Sun [Microsystems] when it came out with Sun Ray, Wyse, Pano -- they all say there is no software in these devices, but that's simply not true. How would it function? How would it get an IP address from the network?" Margevicius said. "The term zero is a misnomer -- there is no such thing as a zero client."
Instead, zero clients typically include an embedded BIOS-like piece of software that is much lighter than thin client or PCs, so they boot faster and require little to no management.
Why use zero clients?
With those benefits, zero clients can serve as a good alternative to PCs and thin clients for IT pros who want to minimize end-user device management.
Such devices can also save power. Albert Alvarez, the desktop virtualization technical lead for Miami-Dade County in Florida, installed Citrix XenDesktop earlier this year. As part of a federal "green" initiative, he needed to replace PCs with something more energy-efficient.
"Basically, we wanted the dumbest end-user device we could find -- a little box with a couple of connections -- to eliminate our desktop management requirements," Alvarez said. "But that device also needed to provide the same experience as a regular PC. Those requirements were tough to meet."
Alvarez ultimately chose Wyse's new zero-client device, Xenith, which works only with Citrix XenDesktop and the Citrix HDX protocol. The device connects to a XenDesktop server, and all of a user's configurations are automatically delivered, with everything managed on the server side.
With HDX protocol support, Alvarez said end users can use video, Web conferencing, and other high-resolution applications that they would normally get with a PC. So far, about 2,000 desktops have been switched to zero clients, and Alvarez said he hopes to virtualize 60% of the 30,000-seat enterprise this way.
The organization could have repurposed its existing computers and continued using them with XenDesktop, which would have significantly lowered the upfront cost of the project, but the long-term savings took precedence, Alvarez said.
"Because this is a green project, we were looking at the entire lifecycle and the power savings. This device uses seven watts, versus 150 to 300 watts, per hour for PCs," he said. "That makes a big difference in long-term cost savings."
Pano Logic Inc. also offers a zero-client device and touts additional benefits over desktop PC, including a much faster boot-up process and better security. "With a [zero-client] device, since there is nothing on it, you can toss it out the door, and it won't matter," a Pano Logic spokesperson said.
Zero-client devices are also available from large vendors including Dell, which jumped on the bandwagon with its own Dell zero-client device for VMware View and PC-over-IP technology.
These devices are also typically less expensive than thin clients, lowering the cost of desktop virtualization projects. For instance, Pano recently launched a promo package deal called Pano Express that it says gives companies virtual desktop infrastructure (VDI) for the lowest cost per seat on the market. The package includes Pano's zero-client device, a preconfigured 50-user suite with VMware vSphere Essentials, Microsoft Windows 7 licenses, and server and storage hardware for $489 per seat.
The trouble with zero client devices
The biggest problem with zero client devices is that they are proprietary. "Zero clients are fixed-function devices, preconfigured with one protocol, so it poses a vendor lock-in issue," Margevicius said.
In addition, zero clients are positioned to last eight to 10 years, but it is very difficult to predict which type of protocol will prevail in the rapidly evolving desktop virtualization market.
"What happens when a better protocol comes out in two years?" Margevicius said. "You are running the risk of being stuck on an old technology."
With that in mind, IT pros should ask vendors about zero-client upgrade policies or consider using a device that offers some manageability. With thin clients, for instance, updates can be applied, and IT pros can upgrade to better protocols as they become available, Margevicius said.