The 'Penn State Automatic Computer'

November 11, 2015

UNIVERSITY PARK, Pa. — Harold I. Tarpley was an unlikely candidate to lead Penn State into the computer age. A Kansas native, he had just earned a master’s degree from the University of Illinois when he joined the Penn State faculty in 1923. His longtime classroom forte was power generation and transmission.

In 1953, only a handful of universities had computers up and running or in the developmental stage. Tarpley became interested in computers when he wondered how they could help control the efficient flow of power in complex electrical grids. But he recognized their vast potential and had already supervised construction of five analog machines for Penn State’s computer lab.

Advancing technology was making the analogs obsolete. "A few years ago the electronic computer was pretty much a laboratory 'child,' " he proclaimed. "With great suddenness this child has become a giant."

He and Arthur Waynick, head of the electrical engineering department, set out to build their own "giant." They secured $25,000 in University funds and $17,000 from the National Science Foundation for constructing PENNSTAC — Penn State Automatic Computer. The machine they envisioned would cost $300,000 on the commercial market. Yet building it from scratch, Tarpley said, would provide his team of faculty and graduate students invaluable hands-on experience.

Gifts in kind came from the private sector. It didn’t hurt that Dean of the College of Engineering Eric Walker had a close relationship with Tom Watson, head of IBM, whom he brought to campus to see the partially assembled PENNSTAC. Watson took note of Tarpley’s lack of success in constructing a magnetic storage drum, essential for the computer’s memory. Soon a drum arrived from IBM.

PENNSTAC finally came to life in Room 6 of the Electrical Engineering Building (West). Its design and construction resulted in more than 60 graduate theses. Later, researchers in disciplines ranging from chemical engineering to agricultural economics to meteorology took advantage of its computing power — enormous for its time, though today easily outdone by that of a laptop computer.

According to a 1957 account in the Daily Collegian student newspaper, PENNSTAC could "perform 1,400 additions of 10-digit numbers in one second, and its magnetic drum can store 2.5 thousand 10-digit figures."

By current standards, PENNSTAC was slow: it contained more than 1,500 vacuum tubes and was difficult to keep cool. "We could only run PENNSTAC for a few hours at a time before it overheated and we had to shut it down," recalled William Adams, then a grad student and later a faculty member who headed the University’s engineering computer lab.

No matter its crude workings, PENNSTAC proved to be an enormously useful research and training tool, until its retirement in 1968.

  • Penn State Professor Harold Tarpley

    Penn State Professor Harold Tarpley

    IMAGE: Penn State University Archives
  • Penn State Professor and Head of Electrical Engineering Arthur Waynick in 1963

    Penn State Professor and Head of Electrical Engineering Arthur Waynick, in 1963.

    IMAGE: Penn State University Archives
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Last Updated December 15, 2015