ATM Energizes Distributed Computing

Barry Nance

Westinghouse Electric Corp.'s Energy Systems Business Unit (ESBU) is evaluating asynchronous transfer mode (ATM) as a way to lower the overall cost of client/server computing. The ESBU's Nuclear Technology Division, which is based in Monroeville, Pennsylvania, is an engineering services organization that helps design and maintain nuclear power plants. Until recently, it used a supercomputer to automate its computationally intense design and maintenance tasks.

To take advantage of distributed client/server computing, Westinghouse transferred the computing tasks onto a network of Unix workstations (see the figure "ATM Po wers Move from Supercomputer to Client/Server" ). The company uses ATM to link the workstations because ATM could supply sufficient bandwidth to carry the gigabytes of data that the division handles. The network has several compute servers, which execute engineering software in batch mode. Each computer program runs fo r as long as 10 hours. The first processing step transfers many large files from file servers to the compute servers. As it finishes its calculations, hours later, each program stores larger data files (hundreds of megabytes) back on the file servers.

The resulting data traffic calls for a network capable of supporting both high average bandwidths and occasional usage peaks. Each calculation program needs to store and retrieve data at a rate of about 10 Mbps, with peak loads of 40 to 60 Mbps. Sixteen or more programs may run concurrently. The network currently consists of two clusters with four compute servers each.

The division uses both Hewlett- Packard P735 and Sun Microsystems' Sparc 10 and 690 workstations. The HP workstations act as compute servers, and the Sun Sparc workstations act as file and data servers. The Sun workstations also operate as routers that link the company's Ethernet LANs to the ATM network via Ethernet switches from Fore Systems.

The decision to move from a supercomputer environment to a distributed architecture was primarily based on cost. Maintaining and operating the supercomputer drained millions of dollars per year, an expense the company wanted to reduce without sacrificing timeliness. In addition, the distributed client/server architecture lends itself to interactive applications, a direction Westinghouse wants to take with its networked desktop computers. The batch-mode supercomputer doesn't fit into the company's plans for computing within the Nuclear Technology Division.

Today, the applications are still mostly batch-processing programs. However, the company plans to develop interactive applications using visualization software. The fast ATM network, the designers say, will be part of the batch-to-interactive software development transition because the new software will generate even more data than the old batch-mode programs did. Westinghouse expects to build database front-end software, with a graphical look and feel. Engineers will then be able to view the results visually, instead of having to interpret hard-copy numbers.

---

ATM Powers Move from Supercomputer to Client/Server

illustration_link (29 Kbytes)

ATM is a technology for today at a Westinghouse division that designs nuclear power plants.