Friedrich Ludwig Bauer was a German mathematician and one of the most influential European computer scientists of the postwar era. His name is far less well known than those of Turing or Dijkstra, yet many ideas that are now considered fundamental to programming are closely associated with his work.

One of the Founders of Computer Science in Germany

After World War II, Bauer worked at the Technical University of Munich and became one of the people who effectively built the German school of computer science. At the time, computer science was still emerging as a discipline in its own right.

The Creator of the Term “Software Engineering”

Friedrich Bauer is widely credited with coining the term software engineering.

By the late 1960s, software projects were becoming increasingly complex. Large systems routinely ran over budget, missed deadlines, and failed to meet expectations. This phenomenon would later become known as the “software crisis.”

At the 1968 NATO Software Engineering Conference, Bauer strongly promoted the idea that software development should become an engineering discipline rather than a craft practiced by individual programmers.

Today, software engineering is recognized worldwide as a profession. When Bauer introduced the term, however, he was emphasizing something broader: programming should be treated as a true engineering activity.

ALGOL and Structured Programming

Bauer played an important role in the development of the ALGOL programming language, which had a profound influence on later languages, including:

• Pascal
• C
• Ada
• many modern programming languages

He was also an advocate of formal approaches to programming and helped develop the foundations of structured programming before those ideas became widely known through the work of Dijkstra.

The Bauer Stack — One of His Most Important Contributions

In 1960, Bauer and his colleagues developed a method for transforming arithmetic expressions that became known as the Bauer stack.

This work laid the foundation for expression-parsing algorithms used in compilers. Virtually every modern compiler relies on ideas that grew out of this research.

The Bauer stack solved a fundamental problem: how a computer could correctly interpret mathematical expressions. Bauer devised a way to organize operators and operands in a stack so that expressions could be evaluated in the proper arithmetic order and, just as importantly, processed efficiently on the computers of the time.

Computer Cryptography

During the 1980s, Bauer became deeply involved in the history of cryptography and the study of cipher machines used during World War II. He collected documents on German encryption systems and gathered firsthand accounts from people who had worked with them. Based on this research, he produced several influential works on the history of cryptography and helped preserve a great deal of information about European cryptographic systems.

One particularly important outcome of his work was his research on the contribution of Polish cryptographers to the breaking of Enigma. Before Bauer’s publications, even many specialists believed that the story of Enigma-breaking began at Bletchley Park. Bauer carefully reconstructed one of the most fascinating engineering stories of the twentieth century and brought attention to participants whose achievements might otherwise have been forgotten.