Memories of Niklaus Wirth
Turing Award winner, computer pioneer, and inventor of influential programming languages, Niklaus Wirth’s achievements in the field of computer science are far-reaching. To this day, his contributions have had a decisive influence on computer science and have inspired generations of programmers.
The following memories and tributes from former team members, colleagues, and students provide a glimpse into the significant impact left by Niklaus Wirth.
You can find more memories from current and former D-INFK Faculty here.
11 January 2024
Hanspeter Mössenböck
Professor, Johannes Kepler University Linz (AT)
I joined ETH as a young assistant professor in 1988 and had the privilege to work at the Institute for Computer Systems and to become a member of Niklaus Wirth's team.
Since my student days, Niklaus was a hero to me, a world-renowned pioneer of computing, whom I met with deep respect and shyness. But I quickly learned that he was actually a quite approachable and modest man, a person who was absolutely passionate and uncompromising about his work. As much as he was a scientist, he was an engineer, a man who not only created highly influential programming languages and systems but also demanded them to be simple, efficient and reliable. "Make it as simple as possible" was his credo, which he impressively demonstrated to us.
I was deeply honored by Niklaus' confidence in me as his much younger colleague. He even entrusted me with his lecture on compiler construction, which I regarded as the holy grail of computer science education at ETH. I learned a lot from Niklaus. He was my teacher, my idol, and a good friend.
Just a week before he passed away he sent me a foreword for my new book on compiler construction. He worked and was helpful to others until the very end.
Good bye, Niklaus! You had a deep impact on the world of computing and influenced generations of programmers. Thank you!
Michael Grossniklaus
Professor, University of Konstanz (DE)
The first time I came across the name “Niklaus Wirth” was when learning PASCAL as a high-school student in the early 1990s. Realizing that a Swiss professor was so influential in this field had a significant impact on me and was a major factor in my decision to study computer science at ETH Zurich.
As a student, I had the privilege to study under Niklaus Wirth as part of one of the last cohorts that he taught. In “Digitaltechnik”, he showed us how to design an entire CPU (“Hercules”) and realize it on an FPGA within his Ceres-3 workstation. In “Systemsoftware”, he had us delve into every corner of the Oberon operating system. Later, through my Ph.D. advisor, Moira C. Norrie, I even had the pleasure of meeting Niklaus Wirth privately on a couple of occasions.
Looking back, three points are most remarkable to me personally among the countless achievements and qualities of Niklaus Wirth.
- His uncompromising passion for simplicity and elegance in everything he worked on, which is a mindset that we often sorely lack in today’s (academic) world, and that he carried with him long after his retirement.
- His dedication to teaching by creating his own textbooks together with entire ecosystems of hard- and software that could be examined and understood from beginning to end, which are a treasure chest that we still profit from today.
- His humor, modesty, and patience that showed, for example, whenever yet another know-it-all student asked why C was (allegedly) more successful than PASCAL and he simply answered: “If you want to be successful in this world, you need the courage to be ugly.”
On January 1, we lost a brilliant mind, an amazing teacher, and a humble person! But I take solace in knowing that his legacy lives on. Thank you, Niklaus Wirth!
Laszlo Böszörmenyi
Professor Emeritus, University of Klagenfurt (AT)
Editor of the book "The School of Niklaus Wirth" containing a number of essays by Wirth's scholars.
We spoke on the phone only 1-2 weeks ago, and he seemed to be in a good mood. Death must have taken hold of him quickly – and hopefully with little pain. I held Niklaus Wirth in high esteem and was very fond of him. I got to know him in 1977, and of course, I admired the famous professor first and foremost – but even then, I was struck by his simple and humorous humanity.
Life brought us together again and again, mainly in Zurich, but he also visited us a few times, first in Budapest and then in Klagenfurt. Over time, our relationship became more and more intimate, warm and friendly. We looked at many phenomena in life and computer science in a very similar way. I kept motivating him to write his biography. He wrote and sent me several chapters for correction but he did not publish them. Maybe somebody will do this later.
His modesty was his extraordinary characteristic. It came from the deepest core of his being. Before a lecture in Klagenfurt, I introduced him and said that his excellent engineering skill was concentrating on the essentials, like poets who put their ideas in short verses. (The German word for a poet – “Dichter” – means somebody who “compresses”, who makes things compact.) This amused him greatly; he laughed and thanked me for making him a poet. His dry sense of humour was another essential characteristic, which also helped him remain modest and avoid exaggeration.
All of this – and who knows what else – ultimately made him one of the most amiable persons I have ever met. I am infinitely grateful that I became his friend – and infinitely saddened by the loss of him.
Cuno Pfister, Dominik Gruntz, Stephan Koch and Beat Heeb, Oberon microsystems AG, Zurich (CH)
Niklaus Wirth was a member of the Board of Directors at Oberon microsystems for many years. He was the doctoral supervisor of Beat and Cuno. Dominik was a doctoral student of Gaston Gonnet and also a member of the Board of Directors of Oberon microsystems.
Niklaus Wirth and his programming language Oberon have shaped our thinking and Oberon even became part of our company name.
Niklaus was always ready to make the extra effort, and to take the risk of searching for simpler solutions to difficult problems. Even today, we regularly benefit from his art of decomposing complex software systems into modules with explicit interfaces—a still underestimated means of managing complexity.
It was a privilege to have him as teacher, to work with him as PhD students, or to get his support for our company as a honored member of the board. We fondly remember last year, when he honored us with a visit in very good spirits.
We will miss him.
Immo Noack
D-INFK Alumnus (CH)
My employment
In autumn 1978, I started my job as a technician in the Lilith working group at what was then the Institute of Computer Science and Niklaus and I have stayed in touch ever since.
I can still remember my interview at the time, when Niklaus asked me about my programming skills. My answer was: "Very little, just Assembler and a little Fortran." I tried to score a few points and added: "First steps with Pascal." But I had no real idea who was sitting opposite me and he didn't even make a face. Fortunately, he didn't ask me for any details about Pascal. However, I got the job.
Supervisor
Niklaus was a demanding but also supportive boss. The assistants somewhat feared the Monday colloquium or the one-on-one meetings in which they had to report on their work. Niklaus always wanted to know everything down to the last detail and questioned a lot of things.
Episodes of Lilith
In addition to the working memory, initially 256 KByte, later 512 KByte, the Honeywell Bull Drive was selected as the storage medium, which worked with a 10 MByte removable disc. A removable disc initially cost around CHF 800 and the institute kept precise records of who was working with how many discs and any further need for a disc had to be explained to Niklaus very clearly.
Matrix printers were still common in the early 1980s. Thanks to Niklaus' connections to Canon, we were able to connect a laser printer to the Lilith network relatively quickly, the Canon LBP-10, a heavy laser printer with liquid toner that required intensive maintenance, calibration and care.
Ceres-3 episode
When the 100 Ceres-3 computers were built in 1991, we were granted a loan of 700k by the school management. Thanks to a lot of our own work and intensive negotiations, we were able to reduce the costs to 500k, with the rest of the money going back to the school management. The computers were then used for many years in the computer science study programme.
Personal points
- It was important to Niklaus that all developments were related to teaching, whether in terms of software or hardware. He emphasised this time and again. Accordingly, all results were also incorporated into his lectures.
- Niklaus took great care to ensure that available resources (money and staff) were used very sparingly. Royalties from his book sales were channelled into an ETH fund, which gave him a certain independence. He always refused to take a stake in companies. His statement on the subject: ETH pays me a decent salary, that's enough.
- Another amusing memory is the gift Niklaus once gave Carl August Zehnder: a self-made periscope so that Carl August could still see over his desk, which was overflowing with files.
- His travel reports were fascinating, in which he documented his experiences in a detailed and exciting way. Here, too, his style of expression was very precise and varied.
- Niklaus was enthusiastic about flying, and during his time in the USA he flew small sports aircraft from time to time. His absolute highlight was a flight in a military jet, in which he was able to fly a loop in a pressure suit. I'm not quite sure how far he or the pilot flew, but his eyes always lit up when he told this story.
- Niklaus was curious and interested in technology, such as quantum computers, right up to the end. He also had them explained to him by an ETH physics professor he knew, but still had to admit that he didn't fully understand how they worked.
- The nice thing is that the time with Niklaus has left its mark on many former colleagues and assistants and Niklaus is the connecting element. For example, a group of former doctoral students who live and work on the US West Coast meet regularly to exchange ideas and have dinner.
When I think of Niklaus, the following spontaneously comes to mind: Modest, curious, cosmopolitan, grateful, good listener and counsellor, a broad interest and knowledge, not only in computer science. He was interested in world affairs, politics, music. His family, children, grandchildren and great-grandchildren were also important to him.
It is difficult to say goodbye to Niklaus for good. He has shaped my life and I am grateful to him for that. I will remember him fondly.
Hans Eberle
Senior Research Scientist, NVIDIA (USA)
Niklaus Wirth was my teacher, colleague, mentor and friend. His profound impact on both my professional path and personal life has been immeasurable.
I first encountered Niklaus in a programming course at ETH that was part of my electrical engineering curriculum. We coded our programming assignments in Pascal-S executing them on a CDC 6000 mainframe computer. The course ignited my interest in programming and motivated me to take a course in Fortran during the subsequent semester break eager to master a 'real' programming language prevalent in industrial applications. It was only during this course that I began to truly value the minimalist philosophy Niklaus applied to creating programming languages and computing systems, in general, an approach that resulted in efficient and comprehensible designs.
After obtaining my diploma degree, I had the privilege of becoming a PhD student under Niklaus' guidance, further enhancing my admiration for his design principles, which I would succinctly describe as 'Less is More'.
Niklaus' mentorship was a pivotal factor in my journey to the Silicon Valley, providing invaluable guidance throughout my research endeavors at various industrial research laboratories.
In today's world, where we are building increasingly complex systems, Niklaus' emphasis on minimalism in design becomes even more critical. It helps us to not only understand but also clearly explain the intricacies of what we are creating.
Beverly Sanders
Professor, University of Florida (USA)
I was very sad to learn the news about Niklaus Wirth. I joined ETH in 1986, first as a research scientist and later became an assistant professor in the Institute for Computer Systems. I look back with great fondness on my time there.
Although I was not primarily involved in its development, my time at ETH coincided with Oberon and the Ceres workstation. The Ceres, like the Lilith computer that preceded it, was unique in that it was a complete system, built from the ground up - including the hardware, systems software, and applications - by a very small group of people. I appreciated its elegance, conceptual clarity, and simplicity (but not being too simple). To this day, when I teach a course on programming language principles, I describe the progression of ideas from Pascal to Modula 2 to Oberon to Oberon 2 as these languages provide a brilliant distillation of important concepts. The beautiful location in Zurich together with the presence of Niklaus Wirth resulted in a constant stream of visitors. It was a great privilege to be able to meet many interesting people there.
As a young American woman, taking a job at ETH resulted in quite a bit of culture shock. Several others have written about Klaus’s sociability and humble personality. I always felt he was the person in the department who was most likely to “get” my questions and concerns and remain grateful for his kindness and support.
A random memory:
In those days, he would spend time during the summer and breaks at his farmhouse in Appenzell, where he did not have a phone. If one needed to communicate with him, the Swiss PTT would usually deliver a letter the next day.
Michael Franz
Distinguished Professor, University of California (USA)
Niklaus Wirth's book "Algorithmen und Datenstrukturen" inspired me to study computer science in the first place. Little did I know at the time that Klaus himself would later become my teacher, my mentor, and my friend.
Thank you, Klaus.
An anecdote:
In January 1998, NASA announced that former astronaut and U.S. Senator John Glenn would be traveling to space, making him (at age 77) "the oldest person to fly in space." Just days later, Klaus Wirth asked if he could come for a "research visit" and stay with me in my guest room for a couple of weeks.
As it turned out, after being fascinated with flying model airplanes for decades, Wirth had decided to fulfill a childhood dream and learn how to fly a real plane. "If John Glenn can fly to space at his age, then I can learn how to fly" he told me.
But critically, his wife Diana would find this far too risky, so he planned to tell her only after the fact. Hence his "research visit" at Irvine in March 1998: each morning, he would drive to Palomar airfield in nearby Carlsbad to take lessons at a private flight school there, and each evening, we would have dinner and talk for hours.
I don't know what Diana said when she ultimately found out, but the flying lessons made Klaus very happy.
Hans-Peter Frei
First chairperson of the newly founded
Department of Computer Science at ETH Zurich (CH)
It was with great sadness that I learned of the sudden death of Niklaus Wirth with whom I had spoken on the phone shortly before Christmas 2023. On the phone, I did not notice any sign of a medical problem; this made his passing even more shocking.
I got to know and appreciate Klaus as my thesis advisor back in the 1970s. Already then – before Pascal was officially born – Klaus was one of the driving forces in the then growing CS section. His connections to the world-wide CS community and his lucid ideas about where the future of CS should go were groundbreaking for the development of computer science at ETH. His commitment to simplicity and transparency in the design of hardware and software shaped the Institute to be. He liked teaching courses and provided a great deal of advice and support to both students and young computer scientists.
In his daily work, Klaus concentrated on his engineering centered research and developments and – as we all know – performed on a level that was acknowledged all over the scientific world. He was awarded numerous honorary degrees as well as the Turing Award, the ‘Nobel Prize of Computer Science’. It is to say that he hesitated to get involved in organizational and administrative matters, he just disliked them. One exception, however, was in the years when the members of the Institute strived for computer science to become an official ETH curriculum – a Division of Computer Science and later a Department. He intensively engaged in these endeavors and was of valuable help when seemingly insurmountable obstacles had to be overcome.
As a colleague in the newly founded Department, I appreciated Klaus as friendly, courteous and helpful and enjoyed to work with him, always in a goal-oriented manner. Discussions with him were invariably stimulating and inspiring. In addition, I not only met him in research and teaching environments, but also on a private level in both Switzerland and California. I experienced him as a warm and friendly guest or host. I will greatly miss Klaus as an amiable colleague and friend and will always remember him fondly.
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