Distributed Client and Fat vs Thin Clients

By Mike Buffington, Chief Architect         From: 2015 Q2 Newsletter

In 1998, when I first started working at Nexus Software, teller terminals were mostly Personal Computers running NT or Windows 98. The teller application ran on the PC, with devices such as cash dispensers and printers being controlled directly from the PC. The term “fat” client was coined for such terminals as they hosted a lot of software both on their hard drive and running on their CPU. Nexus Software’s Branch product was designed for such fat clients: installing the Nexus device management software directly on the PC along with the configuration of how those devices connect and operate.

Updating software and device configurations across a financial institution’s fat clients is challenging as every terminal has to be updated in some manner. In 2005, Nexus Software introduced the Distributed Client product to address this challenge. With Distributed Client both device management software and device configurations are stored on a central server with updates pushed from the server to client terminals. Terminals need only be touched once to seed them with Distributed Client. All future updates can be driven from the central server.

When I returned to Nexus Software in 2011 it was to discover that Distributed Client promised more than it delivered. Since the re-launch of the company under new management, Nexus has worked diligently to provide quick and reliable updates of client terminals as Distributed Client had originally touted.

Thin clients are an increasingly popular alternative to fat clients. With thin client, the teller application runs on a server and its screens are presented on the client workstation. This allows for client workstations that cost less than PCs. Nothing is stored on the client workstation so sensitive data cannot be lost if someone makes off with the workstation. Servers are located in the data center simplifying updates. Nexus Software products have been making all of this possible on thin clients since 2005, along with numerous improvements and enhancements introduced in the intervening years.

One challenge in the thin client environment lies in communicating with devices located in the branch from servers located in the data center. The internet lies between the two introducing latency through distance and whatever routers the internet throws between them. Back in 2005, Nexus struggled to gain enough performance to control more than a single device from a server at a time. The technology to carry serial, parallel, and USB signals across the internet has improved tremendously since then, increasing the number of devices that can be controlled from a server, and today Nexus has thousands of thin client workstations in operation around the globe. Check with Nexus Software for device compatibility for your environment.

Thin client usage breaks down into two camps. The first camp has many applications running on a server each presenting their screens on different clients. Citrix’s XenApp and Microsoft’s Remote Desktop Services are two prominent examples of this camp. We refer to them as “session” based as each application is hosted on the server in its own session. The second thin client camp virtualizes the entire client workstation instead of just the application. VMware and Citrix’s XenDesktop are prominent in this camp.

While Distributed Client is applicable in all thin client environments, it does provide powerful features applicable to a session based thin client. A session based server requires the configuration of every device that can be served by applications running on the server. This can be a very large number of devices. Distributed Client simplifies the configuration by automatically provisioning each application session with only the devices the session requires.