October 19, 2026, 7:47 am | Read time: 4 minutes
On June 19, 2026, a woman celebrated her 100th birthday, known for saving computer-controlled systems from crashing with a simple method. The story began in the early 1960s in the research department of a telephone company. In this article, TECHBOOK explains why the invention not only received one of the first software patents but is still found today in the internet and AI applications.
There is hardly anything more pointless than listening to the melody in a telephone hold queue. The interlude is only briefly interrupted by a computer voice that informs a caller at regular intervals: “The next customer service representative will be available for you in X minutes.”
This roughly describes the situation telephone companies faced when computer systems replaced the “switchboard operators” who manually connected calls in the early days of telephony.
In the early 1960s, the global telephone network was becoming increasingly dense. Therefore, computer-controlled systems were supposed to untangle potential bottlenecks. Unfortunately, the opposite initially happened, as the new technology regularly collapsed due to the increased call volume.
The Real Problem
The high number of calls was a problem. However, the new technology was supposed to handle many other necessary tasks, such as freeing up lines, ending connections, and billing charges.
It was easy to see that each task had a different priority. Connecting a phone call naturally had the highest priority, while billing was among the lower-priority tasks. Erna Schneider Hoover recognized this at the time. She worked at the so-called Bell Lab, the research center of the American telephone company AT&T.
Together with Barry J. Eckhart, she worked on an algorithm to prioritize the various computer-controlled tasks. The solution from the two developers sounds simple today. During times when many people wanted to make calls, other lower-priority tasks were postponed. When the number of calls in the telephone network decreased, the postponed tasks were completed.
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Software Patent for a Brilliant Idea
The method could perhaps be compared to a situation in a supermarket. When there were only a few customers in the store, the cashier, for example, took care of stocking shelves or receiving deliveries. When a line formed at the checkout, all other tasks were put aside, and the cashier served the customers. The postponed work was continued later.
Erna Schneider Hoover and Barry J. Eckhart called their method “Feedback Control Monitor for Stored Program Data Processing System.” For this, the two developers received one of the first software patents in 1971. The innovative idea showed that a computer system did not need more powerful hardware but just an instruction to set priorities independently.
Thanks to the algorithm developed by Erna Schneider Hoover, computer-controlled systems were able to constantly monitor their own workload and process pending tasks without interruption. For that time, it was a tremendous development achievement because computers then processed programs strictly in sequence.
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A Method That Still Works Today
Later, the method was repeatedly adopted in computer science and still protects computers from crashing today. Procedures like Load Shedding, Traffic Control, or Adaptive Resource Management are familiar to most developers. They all are based on the development by Erna Schneider Hoover.
Load Shedding is used, for example, in streaming. During a major sporting event, preview images are loaded more slowly in the background to keep the video stream stable.
Traffic Control manages traffic so that vehicles do not block or endanger each other. This is done, for example, with traffic lights, sensors, and computers. The system automatically adjusts the signal times to the current traffic situation and, for example, extends the green phases at busy intersections.
Adaptive Resource Management is found, for example, on cloud platforms. The system constantly monitors its own workload and dynamically allocates available computing power to particularly important applications. If a service suddenly requires more capacity, it receives additional resources. Less urgent processes are moved further back in the queue.
Ultimately, the control of mobile networks or AI data centers is also based on Erna Schneider Hoover’s idea. Without her development, there would be plenty of congestion on the digital highways of the internet.