Programming computers is difficult, especially if you want programs to work correctly. There are heated debates on the best methods to reach this. To better understand what programming is and how it should be done, CWI’s PhD student Gauthier van den Hove reconstructed and analyzed the first ALGOL 60 system, a computer system designed and implemented at the Mathematical Centre (MC, now CWI). On 15 February he defends his PhD thesis ‘New Insights from Old Programs - The Structure of the First ALGOL 60 System’ at the University of Amsterdam. Van den Hove’s results are not only interesting for computer scientists, but also for science historians and philosophers. The thesis has a foreword written by the famous American computer science pioneer and Turing Award winner Donald Knuth.

Prof. Donald Knuth (Stanford University), who is also known for creating the TeX typesetting system, wrote the foreword to this thesis in 2017. Knuth: “The present book is a major addition to the literature. It is destined to become a classic, because it not only unveils the beauty of a profoundly original and influential computer program, it also explains the enormous significance of this program (...). This fascinating book serves as a model of historical scholarship: It proves that great software makes a great story, without skimping on details.”

Gauthier van den Hove tells about his research: “Much can be learned about computer programming and its methods by studying exemplary programs. I reconstructed a particular well-crafted computer program: the first ALGOL 60 system, designed and implemented at the Mathematical Center (MC), now CWI, by Edsger Dijkstra and Jaap Zonneveld, with the assistance of Ms. Fiek Christen and Ms. Marlene Römgens, on an Electrologica X1 computer. My research consists of three parts. First, the two facets of the problem that the MC team was facing, namely the ALGOL 60 language and the X1 computer. Second, the principles of its solution - the implementation choices made by the MC team compared to other possibilities. Third, the details of the MC ALGOL 60 system, reverse engineered from its X1 assembler source.”

Van den Hove’s promotor Prof. Paul Klint (CWI and UvA) adds: “It's a unique reconstruction and analysis of one of the most influential compilers in the history of computer science”. Prof. Donald Knuth writes in his foreword: “Large computer programs represent some of the most significant intellectual achievements in human history. Well-written books about such masterworks will inevitably rub off on programmers young and old, inspiring us to continue extending our reach.”

This research has been carried out in the Software Analysis and Transformation (SWAT) research group at CWI in Amsterdam. SWAT studies the design, construction and evolution of software systems to understand them and to improve their quality. The research was funded by NWO.

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