Although many organisations are satisfied with conventional desktop PCs, some want to manage their systems so tightly that they have replaced their desktop computers with thin clients connected to back-office servers that provide the computing and storage resources. These servers usually deliver a full Windows desktop and applications to users via a network connection. Users connect via a protocol such as Microsoft RDP (Remote Desktop Protocol) or Citrix ICA (Independent Computing Architecture), so this approach also works well for remote workers. However, the server environment is fairly complex and requires careful management by skilled IT staff. Also, some applications work better in this model than others. For example, one user running a processor-intensive application would probably affect all the other users of the application server. There’s also a risk that a single user could bring down the entire application server by running a program that has a bug or turns out to be infected with a virus.
By contrast, blade-based desktop PCs offer many of the advantages and few of the disadvantages of traditional thin-client systems. With the promise of predictable performance, excellent support for remote workers, lower costs of ownership plus better security, reliability and manageability, blade PCs are rapidly gaining ground in businesses.
Most IT staff would also agree that desktop PCs are a headache when it comes to security. For example, removable media drives and other USB storage devices could be used to steal information or to introduce a virus or other malware into the network. Some organisations also have particularly stringent security procedures to protect data on desktop systems. For instance, some companies use desktop PCs with removable hard drives and insist that users remove and lock away the hard disks when they leave their desks. USB sticks and removable hard drives can be tricky to manage using traditional desktop PCs, but blade PCs are normally located in a secure datacentre, thus preventing physical access to the disk drives and USB ports.
Blade PC architectures
ClearCube was the first vendor to offer blade PCs, and it remains the only one to concentrate purely on desktop hardware. ClearCube's solution is built around a rack-mounted blade chassis There are two chassis types: the 3U R4300, which houses eight R-series blades, and the 6U A3000, which houses ten A-series blades — each blade being essentially a powerful PC. The rack itself is normally housed out of harm’s way in a datacentre: a standard six-foot rack can accommodate fourteen R-series chassis for a total of 112 blades or seven A-series chassis for a total of 70 blades.
Obviously users need a monitor, mouse and keyboard on their desk, but rather than connecting these to a thin client or desktop PC, ClearCube uses a video-cassette-sized cable connection unit, called a 'user port'. The company sells two types of port, both of which provide connections for local printers and peripherals that can be tightly controlled by management software to prevent unauthorised use. C/Port devices use analogue electronics to minimise delays and connect to the blade with up to 200m of standard Cat 5 cabling. By contrast, I/Port devices use a digital interface and standard TCP/IP signalling, so they can be connected with standard LAN and WAN links over unlimited distances. Companies could use I/Ports to build a disaster recovery system for their desktop users, for example, by putting the racks of ClearCube blades in a secure hosting facility and connecting their desktop users via I/Ports and internet links.
Last year HP began offering blade desktops along similar lines to ClearCube's products. HP’s Blade Workstation is based on its C-Class blades. For normal desktop users HP also offers lower-specification blades based on its bc2500 Blade PC. HP does not offer a simple ‘port’-type option to minimise complexity on the desktop, so HP blade PCs must be used with thin clients or ordinary desktop PCs. HP reckons a typical Blade Workstation deployment would cost about $4,000 (~£2,000) per desktop, while Blade PCs come in at about $1,200 (~£600) per user.
IBM is a major presence in the blade market with its BladeCenter servers. The company also launched its Workstation Blade in May, and for a year or so has been offering blade servers configured with Citrix Presentation Server or VMware virtualisation tools to deliver managed desktops to users equipped with thin-client terminals.
