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23 April 2001

Thin Clients: Looking Back to the Future

The emergence of thin clients might appear to be a return to the past, involving a dumbing down of the operator interface (OI).

But today's thin client is far from dumb. It retains the characteristics that once made the PC so attractive, while simplifying maintenance and administration of large systems.

The PC revolution may be over, some say—but its gains will be preserved in convincing fashion. With the proliferation of high-speed networks such as Ethernet, the PC revolution brought a tremendous improvement in communications bandwidth. PC hardware and software standards made it technically and economically possible to build bridges between islands of automation, allowing higher levels of process control.

Networking brought a new architectural model, the client-server. On this basis emerged a new generation of OIs. The PC-based OI, with its sophisticated graphical display, elevated from a peripheral to self-contained peer device that functioned as a client (data consumer) of a machine controller.

As an OI, it might also function as the client of another PC. However it was still a fat client—fat in the sense that it had a hard drive that stored an operating system, applications, and even system-critical data.

With the thin client, though, applications installed directly on the fat client are pushed back onto a server. The client accesses them as needed, by special open network protocols designed that maximize bandwidth available on a modern high-speed network.

Thus, the thin client can provide sophisticated graphical display without suffering significant performance loss and the hardware baggage of a full-fledged PC.

In one sense, the thin OI has again become a sort of peripheral—unable to stand completely on its own—yet much simpler to operate, purchase, maintain, and secure. The transition to thin—client solutions will be selective as businesses continue to need the flexibility and expandability of a fully powered PC. With their ease of scalability, today's hardware platforms can provide the best of both worlds.

About the Author

Chris Rodie is a senior marketing programs specialist with Rockwell Automation's Industrial Computer/EOI Business in Duluth, Ga. Reach him c/o editors at IC@isa.org.