For more than a decade, thin client technology -- which sends images of a desktop over a network so users can access applications using a simple computer -- has been the quiet doer in desktop circles, slashing the cost of desktop support for travel agencies, banks, retail outlets and other companies with large numbers of computers.
With the rise in virtualisation technology, however, the role of the thin client has changed -- and for the better. As virtualisation expands away from its initial home in the datacentre, it's providing a completely new paradigm for the corporate desktop.
Freed from the constraints of a specific computer, even fully-featured desktops can be run as virtual images from a single server. That's a big improvement from thin-client technology, which has often had to take a lowest-common denominator approach that was not compatible with every application.
Running virtual desktops eliminates this shortcoming, since each virtual desktop is effectively a completely self-contained, full-featured computer. An emerging breed of companies is using this capability -- available in server applications from vendors including VMware and Citrix Systems' Desktop Server to build up desktop farms that let users access their own personalised corporate desktops from anywhere as easily as they might download their e-mail. With such a set-up, remote working becomes a breeze.
A fresh look at thin clients
Because virtualisation allows large numbers of standard desktops to be run from a single server, it has emerged as a game-changing trend that has forced the simple thin-client desktop to reinvent itself. The latest versions of thin-client computing, from market leaders Microsoft, Citrix Systems, Wyse and others, have taken on this challenge and emerged with a range of new methods for allowing users to access their applications.
With the upcoming launch of its major Windows Server 2008 platform, Microsoft has led the charge, offering enhancements to Terminal Services features that improve the capabilities of its RDP (remote desktop protocol) transport service. These improvements include, for example, better remote printing services and the ability for a Terminal Services session to be spread across more than one desktop.
Now that we've gotten beyond the hurdles of compatibility ... it's easy for companies to publish any app they like.
Michael Kleef, Microsoft Australia technology advisor
The latest upgrade to RDP also includes a more efficient graphics algorithm that allows even full 32-bit graphics to be sent to remote desktops -- a must-have if remote desktops are to be able to interact with the enhanced display of Windows Vista's "Aero" desktop technology. Improvements to RDP's graphics handling also mean that remote users can now use applications such as photo and video editing, without having to have expensive multimedia applications running on their systems.
Yet the capability closest to the heart of Microsoft Australia technology advisor Michael Kleef is Terminal Services RemoteApp, a feature that allows companies to publish links to specific applications on any Web page. Rather than having to deal with a complete desktop, this means that any Windows application can be made available to a remote user with a single click. The application, which runs inside a server-hosted virtual machine, behaves exactly as if it were loaded on the user's desktop -- without the bother of actually providing a full desktop.
"Now that we've gotten beyond the hurdles of compatibility [with thin-client servers] we had before, it's easy for companies to publish any app they like," says Kleef. "You can literally have a whole Web page full of apps that your corporate users see, and they simply click an icon to say 'I want to use this one now'."
This method of application delivery contrasts with Microsoft's other new desktop delivery technology, SoftGrid, which uses conventional video streaming protocols to stream applications to desktops for local use. By keeping the applications on the server and allowing remote devices to interact with them using RDP, Microsoft has provided a platform that can be accessed from any device -- including PCs, wirelessly connected laptops, and even PDAs and smartphones.
Although such technology has improved the way thin-client desktops are delivered to users, it has left a few weak spots. For example, a virtual desktop can't interact with devices connected to the USB ports on a user's remote machine. Video, too, has remained elusive given the bandwidth-efficient design of conventional thin client technology.
... because we're sending the file compressed, it's not nearly as big as you'd think.
Ward Nash, Wyse Technology regional sales manager
Improving access to broadband, however, has finally allowed thin-client innovators to bridge these last remaining gulfs. Wyse Technology, whose thin-client terminals are widely used in customer service focused offices, recently figured out how to build this bridge by giving its ThinOS operating system a multimedia capability that lets companies deliver streaming video to remote desktops.
This is made possible by loading relevant video codecs onto the thin client, then creating a second, parallel connection to the server that carries the compressed video alongside the desktop display traffic. A similar approach will soon allow mapping of USB ports from remote desktop to server host, meaning that users will be able to plug their iPod into a thin-client device and synchronise with iTunes running on the host server.
Pushing video and USB over a remote link requires more bandwidth than a desktop image alone, but Wyse Technology regional sales manager, Ward Nash, believes this is less of a problem given that most remote users are connecting over much faster connections than they used to.
"Running multimedia over RDP today just looks like junk," he says. "But because we're sending the file compressed, it's not nearly as big as you'd think. [Bandwidth consumption] all depends on the codec you use to compress your video, and how high the resolution is."
Wherever you may roam
In the short term, such advances mean that remote desktops can finally gain feature parity with conventional desktops -- effectively making the fat client redundant (except, of course, for games and graphics-intensive apps that require absolutely massive amounts of processing power).
In the long term, the ability to offer full-featured desktops to far-away users offers tantalising possibilities.
Remote video delivery, for example, means that an IPTV broadcaster could offer its customers an inexpensive thin-client device -- little more than an LCD screen, keyboard and mouse -- that could be used both as an Internet terminal and a conduit to deliver hundreds of channels of streaming TV.
And remote USB support would allow a photographer to plug their digital SLR camera into a smartphone, then log onto an online photo-archiving service to upload, manipulate and publish the pictures straight from the camera. Because it would be running on a host server, that application could offer the full capabilities of a Windows desktop -- without the cost and bother of managing one. Access to the application could also be sold for a nominal fee per hour, finally enabling the long-discussed "apps-on-tap" model of casual application access.
It took some time, but full virtualisation of remote desktops has finally fulfilled the long-held dream of the thin-client world: to offer a convincing enough user experience that most users won't know the difference. With virtualisation firmly entrenched and remote desktop technology getting better every day, the desktop as we know may never be the same again.