A Primer on Desktop Virtualization Using Thin Clients and Blade PCs

We explain the four major models of remote client solutions on the market today.

The advent of personal computing and productivity applications in the 1980s represented a major turning point in traditional business computing. Suddenly, employees could rapidly collect and analyze business data at low cost (compared to mainframe computing alternatives). This turning point, accompanied by the development of extensive communication and storage networks, resulted in massive proliferation of business computing. It also exponentially increased the need for IT support, creating security holes that exposed enterprises to the potential loss of critical information.

In the wake of these threats, thin clients -- low-cost, centrally managed computers devoid of a hard disk drive and non-essential applications -- have emerged as a more secure alternative to desktop PCs. Research conducted by IDC, Gartner, Zona Research and others shows that thin client computing offers a cost-effective desktop alternative that lowers maintenance costs while delivering increased reliability and security. In a thin-client model, processing and storage are moved to a data center; the access device and display remains at the user’s desk. There are a variety of implementations available today, which are collectively known as “remote client solutions.”

Four major models of remote client solutions exist today:

  • Blade PCs, such as HP Consolidated Client Infrastructure solution (CCI)
  • Virtual PCs, such as Virtual Desktop Infrastructure
  • Server-based computing such as Citrix or Microsoft Terminal Services
  • Application streaming

Each model has its own advantages, and IT must analyze the user and network needs closely to identify what model or combination of models may be best suited to their environment. As you will see later, thin clients are ideal acess devices for end users, regardless of what model of remote client solution you implement.

Blade PCs -- A Dedicated PC in the Data Center

Relying on traditional PC components and running client PC operating systems and applications, blade PCs pair with inexpensive thin clients to create a system that delivers centralized control, increased security and lower costs associated with centrally managed datacenter solutions, while delivering a full PC experience. This consolidated model pools computing hardware resources by moving processor, storage, and networking to the data center. Users are assigned access to their dedicated Windows XP or Vista PC, and in the event of an issue, users can be automatically routed to a new blade PC, without the need for IT manager interaction..

Blade PCs offer a robust solution that provides every user with dedicated processing power. Many vendors use Microsoft Remote Desktop Protocol (RDP) or their own unique protocol (such as HP Remote Graphics Software) to enable communication between the thin client and the blade PC.

Blade PCs offer a consistent and predicatble computing experience, and are easy to size and budget. Blade PCs are ideal for companies that have knowledge workers who demand a cost-effective computing performance, but where IT still wants to simplify management of PCs and increase overall security. The blade PC architecture can ease headaches associated with managing applications on disparate client PCs and drastically lower total cost of ownership (TCO), while optimizing system-wide computing resources. In fact, a July 2007 IDC white paper on blade computing revealed that absolute cost benefits of a desktop replacement architecture could amount to $1,372 per user over the course of three years (see Note 1), which is the typical minimum lifecycle of a desktop PC.

SIDEBAR: Advantages of Blade PCs

  • Best fit for most PC users, as it targets the largest population of PC users in an enterprise
  • Lowest costs for basic productivity and knowledge workers due to cost-effective license and support model
  • Easy to size and budget; removes the need for complex user and server estimates as well as complicated virtualization software
  • Simplified maintenance within the data center through enabling rapid reboot and deployment

Virtual PCs Mimic a PC Environment on the Server

Several technologies have emerged that allow a “virtual OS” within an operating system, such as Virtual Desktop Infrastructure (VDI). In a VDI implementation, the server runs VMWare, Microsoft Virtual Server or other virtualization software to enable many virtual PCs within the server. With the virtual explosion of VMWare in data centers, the skills to deploy VDI are becoming common in many businesses, driving tremendous interest around this new model.

Although virtual PCs still utilize shared resources, the virtual desktop provided to the user can mimic an experience they may have on their traditional desktop. The most common protocol used to deliver the experience is the Microsoft Remote Desktop Protocol (RDP), although both Citrix and HP have enabled VDI support.

Advantages of this protocol include ease of implementation and potential reuse of servers. Virtual PCs can work well for task and basic productivity end users. In some cases, it could work well for knowledge workers, depending on the user requirements. However, they are not ideal if users demand a higher level of performance that can be delivered most cost-effectively by blade PCs.

Server-Based Computing Keeps OS and Applications on the Server

A traditional form of desktop virtualization is server-based computing (SBC), which is a shared resource model. In this model, applications and data are centrally located and executed on servers. This means that applications and data never leave the server, providing key elements of security and reliability to the end users, as well as easier management for the IT organization.

As you can imagine, rolling out applications on central servers is far less complex than on a large PC network. The thin client typically has an operating system far less complex (“thinner”) than a traditional PC, reducing or even eliminating much of the administration and management required for deploying and maintaining a PC. It is not uncommon to see hundreds of users supported on a server, although this is highly dependent on the applications being hosted, the server configurations and how frequently a user places demands on the servers.

The SBC model generally works well for users who are task-oriented, run one or few applications, and do not demand extensive processing resources. SBC provides a very low cost per seat. However, SBC is generally not ideal for productivity or knowledge users.

Application Streaming: Isolating Applications from the Desktop

Another model of desktop virtualization, application streaming, runs isolated applications on the client. Although there are various forms of application streaming, the basic idea is applications are broken down and sent to the local clients over the network where they execute on the local client, often in a virtualized environment. This allows the applications to execute locally, utilizing the processing resources of the local client, while maintaining central control of the applications.

The local client configuration can vary widely, but the virtualized nature of the application execution reduces compatibility and configuration issues. This is a relatively new concept, and is currently being explored further by application providers and IT administrators.


While desktop virtualization addresses problems typical to offices such as small workspaces, increased need for centralized data, and importance of data protection, stumbling blocks naturally arise in such large-scale deployments of remote client solutions. The complexity of the solution demands unique knowledge for deployment and management, and also requires that IT administrators have an extensive understanding of their users’ needs.

The unique technical and business requirements of the computing environment will also indicate the appropriateness of a shared resource model versus a dedicated resource model. In order to dispel myths and demystify remote computing solutions, it is important to clarify how the various technologies fit to provide a complete solution to the corporate IT challenge both today and in the future.

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Note 1: Source: IDC White Paper, July 2007, “Blade PC Computing: A New Paradigm”

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Tad Bodeman is worldwide director of Remote Computing Solutions, Hewlett-Packard. You can reach the author at

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