Server blades have been the fastest-growing segment of the server market for the past two years, while PC blades remain an emerging technology in search of users. Now that Hewlett-Packard and IBM have thrown their market clout and IT influence into the fray, PC blades have a chance to become the first major shift in PC technology since personal computers hit the market in the early 1980s. Or they can become the latest version of the thin client, which has yet to gain much traction as a replacement for desktop PCs.

HP this week will reveal that it has rearchitected its PC-blade platform, the Consolidated Client Infrastructure platform. Introduced just a year ago using processors from Transmeta Corp., which almost immediately stopped making processors, CCI now uses processors from Advanced Micro Devices Inc. HP has completed trials with about 20 customers using the original platform, says Tad Bodeman, director of blade PC and thin clients for HP, and customers can easily upgrade to the new processors.

IBM recently introduced a hybrid approach called the Virtualized Hosted Client Infrastructure platform that uses server blades in combination with software from VMware Inc. and Citrix Systems Inc. to let businesses create as many as 15 virtualized PC blades on a single blade server. Tim Dougherty, director of BladeCenter strategies for IBM, says the platform combines the best attributes of both blade servers and PC blades to create secure client platforms and improve virtualization. Rather than the typical PC-blade implementations of one blade per client, the use of virtualized desktops driven by a server blade can improve utilization rates as much as 80%.

In addition, PC-blade market leader ClearCube Technology last week added a new chassis for its PC-blade platform and management software, and Sun Microsystems revealed an agreement with thin-client specialist Wyse Technology Inc. to jointly market a desktop system using Wyse's thin-client systems and Sun's Secure Global Desktop Software.

While sales of PC blades will total only in the tens of thousands this year, primarily from ClearCube, the moves by major IT vendors to push PC blades and thin clients indicates that long-needed changes may be under way in the enterprise client market, says analyst Rob Enderle of the Enderle Group. "We've been stuck on the same PC architecture since IBM created the first IBM PC," Enderle says. "Back then we didn't have the Web or Ethernet, and the related security exposures hadn't even been contemplated. The industry now realizes it needs to change and blend thinking from the last couple of decades into the mix to create a platform that's more representative of where it needs to be than where it has been."

Science Experiment
But whether PC blades or thin clients will become that new platform remains unclear. Thin clients can suffer from performance problems because several clients share the resources of a single server. In contrast, performance is less of a problem with PC blades because each blade is connected to a single desktop and a single user, although IBM's virtualization technology is moving PC blades closer to the shared-resource approach of thin clients. In addition, PC blades also promise useable lives of as much as five years, as opposed to the three-year replacement cycles associated with conventional desktop PCs, because blades have fewer moving parts than PCs.

Although analyst Enderle believes IBM's effort is primarily a "science experiment," he says the interest shown by HP and IBM will make IT executives more willing to begin experimenting with PC-blade implementations. If so, PC blades within a few years could replace a significant portion of the hundreds of millions of PCs sold each year.