Thin Client

John Cox, Network World

23/02/2005 10:32:15

Thin clients were once as chained to the corporate desktop as full-blown PCs. But that's changing now as wireless LANs and 3G cellular networks become more common.

Using both types of wireless networks, end users can have a relatively simple, diskless notebook-style or handheld device that connects securely, often via a Web interface, to their full suite of enterprise applications running on centrally managed server farms.

The benefits are extensive:

Minimal or no application development for mobile computing.
Data remains on servers, not on clients that can be lost or stolen.
Software updates are made on a few servers, not on many clients.
Real-time access to enterprise data for mobile workers.
A number of recent developments, besides better wireless connections, are fueling interest in wireless thin clients. One is the growing use of operating systems tailored for thin-client devices, especially Windows XP Embedded (XPE ). But lightweight Linux variants also are cropping up.
Other developments include: the growing sophistication of display technology; the ease with which a growing number of peripherals can be used by thin clients, via USB and other high-performance interfaces; a new breed of thin clients designed for wireless deployments, including products from HP, Maxspeed, Neoware, Wyse Technologies and, most recently, Motion Computing.

Motion executives discovered that some of the healthcare customers for the company's line of tablet PCs, running Windows XP Tablet PC Edition, were configuring the devices as thin clients - with no local data storage - linking to Citrix servers.

"The evolution of wireless nets was now allowing the bandwidth for thin-client sessions to work efficiently," says Peter Hunt, vice president of the value-added products division for the Austin, Texas company. "So we thought of using the existing hardware platform but using Windows XP Embedded as the operating system, freezing the software image of the device into a much smaller footprint and using a flash RAM drive instead of a spinning hard drive."

Motion released the M1400TC Table Client in January, priced at about $1,650. The tablet boasts handwriting support, a wide viewing-angle display screen and a built-in fingerprint reader. It has a 10/100M bit/sec Ethernet interface, a PC Card slot, two USB ports and an 802.11g/b WLAN adapter.

Familiar middleware
If much of the client technology is new, the core middleware components of a wireless thin-client deployment are not. They're the same as those used in conventional thin-client desktops. Citrix Systems is the leader in this area, with its suite of software built around its MetaFrame server Independent Computing Architecture (ICA) protocol for client-to-server communications. The most recent, and renamed, release is Citrix MetaFrame Presentation Server 3.0 . Rivals include Microsoft Windows Server 2003 Terminal Services, Tarantella's Secure Global Desktop, Jetro Platforms' CockpIT and BoostIT, and HOB's HOBlink JWT Java software.

Microsoft Terminal Services runs server-based Windows applications, sharing them with multiple users. Microsoft offers a less-developed rival to ICA called Remote Data Protocol.

Lexington Medical Center, a 292-bed complex in West Columbia, S.C., has rolled about 60 of an eventual 100-plus thin clients that link over a Cisco 802.11g/b WLAN to a suite of nursing, clinical and physician applications. These run on a group of 15 Citrix servers, based on HP ProLiant servers with Windows 2000 and Service Pack 4.

The initial focus for the thin clients is to let nurses access a Web-based server application via Citrix for administering and monitoring medications given to patients, usually at bedside.

Sixty Wyse Winterm 945XL thin clients are mounted on mobile carts from Flo Healthcare. The carts, designed for bedside computing, look like pillars mounted on a stable platform of rotating wheels. They are fitted with a flat shelf, with a sealed slotted mount beneath it for the thin-client box, a hidden connection to the WLAN antenna mounted on the rear of the shelf, a slide-out full keyboard, and a 17-inch flat panel display. Lexington Medical chose a sealed lead-acid battery as an alternative to the more expensive nickel metal hydride battery option.

The hospital staff also added to the cart a pistol-like bar-code scanner. Nurses scan their own IDs, the patient IDs and the medications being administered. The application software checks for the "five rights," as they're known: the right patient, medication, time of day, dose and route - the way the drug is given to the patient.

"The nursing staff is really enjoying the system," says Cindy Malphrus, the project manager for the system. "It's preventing errors. We get [application] reports to see how many errors have been prevented. And they think they can actually give meds faster now, although that wasn't a reason for doing this."

By a stroke of good luck, the thin clients were being deployed just as the rest of the IT group completed the hospital-wide WLAN deployment. One goal for the new WLAN is to support wireless VoIP, using Cisco handsets. "You need to have good WLAN coverage for that," says Jeff Jones, Lexington's network administrator. "By designing the WLAN for optimal phone coverage, it gave us good coverage also for our thin clients."

The rollout went off without a hitch. Training sessions showed nurses how to maneuver and adjust the carts, and cautioned them that the stubby black rod was not a handle but the WLAN antenna.

3G is key
One big change in 2004 was the spread of 3G cellular networks that can support data services in the 300K to 500K bit/sec range. Finally catching up were XPE software drivers that would support cellular cards for networks such as Evolution-Data Optimized (EV-DO).

Zumasys is a Lake Forest, Calif., Citrix value-added reseller with more than 70 customers using thin clients on 3G cellular data networks, says Company President Paul Giobbi. He's seeing adoption of diskless, laptop-like thin clients such as Maxspeed's MaxBook married to EV-DO offerings from carriers such as Verizon. "All you need is wireless access to the Internet," he says.

"Think about that: a whole series of thin-client devices accessing not just [personal information manager] and e-mails like today's BlackBerry, but all of your corporate applications," Giobbi says.

One client is Continental Lab Products, a San Diego supplier of laboratory products to life science organizations. The company last year extended its Citrix thin-client deployment by using Panasonic Toughbook laptops and a choice of Sierra Wireless cellular interface cards so sales representatives can access intranet, CRM and ERP applications over Verizon's EV-DO network, BroadbandAccess. Sales representatives can access orders, inventory and other data on the road or at a customer's site. The deployment won best in class recognition in Qualcomm's 2004 3G cdmA-List awards.