For a new approach to teaching the latest in computer operating system design, the computer science department is turning to an age-old toy: model trains. Students gain practical experience designing an operating system to run a motorized train, giving life to highly abstract concepts and achieving tangible results.

The driving force behind the innovation is Arno Puder, assistant professor of computer science, who introduced a simulated train program as the cornerstone of his class on operating system design.

Operating systems that drive computer hardware are enormously complex, responsible for interfacing between the software applications that users employ and the processing units, disks, keyboards, monitors and other hardware. The traditional way to teach operating system design, Puder says, is conceptual and abstract, never quite getting to the code level.

"My approach is to always try to teach students how something ticks on the inside, to make it real," Puder says.

Puder's innovation started in the fall 2003 semester, when he announced to his class that they would be challenged to create a mini operating system from scratch, using freely available open source software and their newly acquired skills in assembly, C++ programming and data structures. To help them see the fruits of their labors, Puder told them, he had created a simulated railroad track and trains that would demonstrate interactions with the operating system.

Little did Puder know that a lifelong train enthusiast, Mike Beck, was a senior computer science major sitting in his classroom. "Do you want a real one?" Beck asked.

That started a round of e-mails, meetings and phone calls as Beck tapped into the network of suppliers that he and his train-enthusiast father have met over the years. With their help, Beck drew up a plan and a budget. With department funds from Chair Dragutin Petkovic and a combination of in-kind contributions and discounts from manufacturers Märklin Trains and Matschke Modellbahn and model train enthusiast Stefano Chiti-Batelli, the model train became a reality. Beck and his dad constructed the track during winter break, and the system formally rolled out April 14, in time for the final project during the spring session.

"I thought it would take a couple of weeks and we'd have a chance to play with it in fall semester," says Beck, who ultimately learned that asking for donations "takes a lot longer than I thought."

The project presented great learning opportunities for computer science grad student Haijie Xiao, as well. She was responsible for changing the simulation display to behave like the real model, responding to the realities of the commands, probes and timing of real engines on a real track.

Xiao liked fine-tuning a tool that will have such an impact on undergraduate students, helping them to "understand the relationships between a PC, an operating system and an application running on the operating system." It's good practice for how software development is done in the real world, she said.

-- Ellen Griffin with Public Affairs Student Writer Elizabeth Davis