With the advent of commoditized computing power and hardware, and a greater push for energy efficiency, desktop virtualization is now once again back in vogue. Like cloud computing, virtualization is an imprecise term that can mean different things. In our Virtualization 101 article we talked about the basics of virtualization — creating multiple instances of an operating system using a single piece of server hardware. This article will focus on a different type of virtualization. As opposed to how operating systems or applications are created or served, there is another type of virtualization that refers to more the delivery and the end-user perspective. This is done by enabling an infrastructure that creates multiple desktop experiences from a central, more powerful computer. There are two ways that this can be achieved: desktop virtualization, and multi-seat computing.
This article will present some basic concepts and definitions to multi-user virtualization, and lay some groundwork for you to decide if it is suitable for your organization.
Virtualized desktops, thin-clients, and on-demand computing are not new concepts. Wyse and Citrix, two companies that are makers of virtualized desktop devices and software, were founded in the 1980s. Sun Microsystems, now part of Oracle, was also a pioneer of virtual desktop technologies. What is new is that computing and networking resources have finally caught up to the vision of "the network is the computer" for more widespread adoption.
On the most basic level, desktop virtualization is when instead of physically turning on a computer or laptop, allowing its operating system located on a physical drive boot up and logging on, you use a device or thin-client that connects to a server on the network. That server then retrieves and accesses a desktop-like interface, including network logon, any applications and data, all via this thin-client setup which projects this interaction on a monitor. If you have fifty employees whose tasks are similar, they can still access their personalized desktop experiences, but without the hassle of waiting for patches or updates to be applied to a physical computer. New applications and patches can be more easily tested and rolled out across an organization. Some of the most valuable benefits of this type of virtualization, is that there is less physical hardware to purchase and maintain, it's easier to deploy and update multiple machines simultaneously, and it often reduces your energy consumption and waste on unneeded hardware.
Compared to desktop virtualization, multi-seat computing is a variation of the same concept but designed for fewer users and thus with proportionately less IT resource demands. Instead of using a thin-client — which still has some rudimentary processing power to process network commands and render graphics — multi-seat computing uses "zero-clients," which have even less processing capabilities. Multiple users are connected to the same physical computer as users on a machine, located in the same location or room using USB connections and directly displaying graphics to multiple computers. This is similar to when one uses Remote Desktop Connection in Windows to log on to a machine, and accesses that computer's processing power to do the work. In fact, Microsoft Windows Multipoint Server is based on the Windows Server 2008 R2, using its Remote Desktop Protocol (RDP) and Terminal Services functionality, with added functionality to facilitate user management in a library or public lab setting. Although the experience is still virtual in the sense that you are not using separate machines for your computing needs, this is better characterized as enhanced desktop sharing instead.
Multi-seat computing takes advantage of the excess and ample computer power available even in retail PCs, and splits that power up amongst several, simultaneous users. 10 to 25 users using the same computing at once is not uncommon, and this makes administration much easier. For users who are mostly accessing information over the Internet, or employees who perform their tasks in the cloud, multi-seat computing is a cost-effective way to add capacity. Moreover, the energy savings can be significant using zero-clients — which often don't need a separate power supply — than a full-fledged PC. For developing countries this can be a significant factor in choosing zero- over even thin-clients or traditional computers.
Whether it is desktop virtualization or multi-seat computing, the main reasons why IT administrators choose to virtualize their desktops are:
Creating more desktops to accommodate more users takes less time in a virtualized multi-user environment, since it generally takes less time to deploy a new desktop instance than creating a new desktop from scratch, even if you have pre-made images already. Read more about disk cloning solutions.
If your desktop instances are served by a server or host computer via lightweight devices, thin- or zero-clients, you would only need to ensure that the desktop image has all the applications and security patches in the image on the main computer, rather than in every single computer.
In addition to the time saved from the above, less energy is needed to run virtualized desktops rather than full desktops. That means also that you would have less hardware that needs to be replaced over the long run.
In a library or nonprofit environment, the most obvious application would be for public computing centers. One can, in theory, serve more patrons and clients using fewer resources, while reducing the total cost of ownership. It would be easier to deploy specialized desktops — ones with games for teens, others for specialized research, or some with specific office apps for job seekers — depending on the hour or demand. For organizations with branch offices or remote workers, desktop virtualization would help standardize technology and applications regardless of geography or location. This also allows data to be separated from a physical machine, prompting some to call this "desktop as a service."
For the most part, desktop virtualization is (for the moment) targeted toward larger enterprises with robust networks to deliver a seamless user experience. Vendors such as VMWare and Citrix tout high-end graphics capabilities to potential users as to assuage them of performance concerns. You would also need a powerful, well managed datacenter in the back-end to support such an environment. Most importantly for an organization, your cost savings are better realized when you shift from managing individual machines to managing thin-client users accessing virtual desktops. However, that wouldn't be the case for, perhaps, a small library serving 20 public computing users (though it's conceivable that a small state or county with a fast and robust network can deliver desktops throughout the branches across the state or county.)
Multi-seat computing, therefore, has been and will continue to be marketed toward the users and organizations that are less well resourced in terms of technology, as well as overall lower user demands. For nominal web browsing and basic PC tasks, multi-seat computing is fully adequate using only a moderately powerful desktop computer. For example, Windows Multipoint Server was released with academic licensing to schools, and only recently made available to libraries and nonprofits at TechSoup. NComputing, a maker of multi-seat computing devices and software, also highlights the impact of their technology in less well-funded school districts with limited IT budgets. Even for sectors with bigger budgets, if data processing or information management is less of a requirement for the end user, they can ostensibly consider multi-seat computing as well.
In sum, with multi-seat computing, you get the benefit of reduced per user cost, but you would still have to ensure that you perform the proper maintenance and security tasks for a shared computer as you would for a physical machine; you just have less machines to manage. With desktop virtualization, it still relies on more traditional server-client infrastructures, but you can have a more robust user experience and better scalability.
As high end hardware becomes niche products needed only by specialized workers like programmers and video editors, yet at the same time lightweight products like smartphones and tablets become more powerful, we can expect the proliferation of virtualized desktop setups in the near future. Virtualized desktops and mutli-seat computing are only the intermediate manifestations of this overall trend. In fact, operating systems themselves are being redesigned to harness the power of ubiquitous networks and cloud services. For IT administrators in nonprofit and libraries, these developments may bring about efficiency not only for the public computing center computer, but perhaps eventually for the entire organization as well.
Image: Virtual network, Shutterstock
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