Ambros Speiser's father Ernst F Speiser (born 6 June 1889) was a Swiss business man of international standing who at the time of Ambros's birth was working in London, England. Ambros was the eldest of his parents' three children. The family were living in Surbiton in Surrey, England and Ambros was brought up there, attending elementary school in Surbiton. In 1931, when Ambros was eight years old, the family moved to Baden in the canton of Aargau in Switzerland. He continued his education in Baden before going to college in Aarau, the capital of the Aargau canton. He explains in  how he became interested in computers:-
After college, I served in the antiaircraft troops for two years, advancing to lieutenant. The gun-sight director that I had to operate was an electromechanical analog computer. It interested me considerably, I studied its intricate mechanism in depth, and, accordingly, I could serve as an instructor to my colleagues. This was my first contact with computing.
Speiser entered the Eidgenössische Technische Hochschule Zürich (ETH) in 1944 where he studied electrical engineering. He visited Maurice Wilkes' computing laboratory in Cambridge, England, in 1947 and realised the potential of the digital computers that were being designed there. It was this experience that made him decide that he wanted to make digital computers a major part of his life. Returning to the ETH, he made contact with Eduard Stiefel who was working towards founding the Institute for Applied Mathematics in ETH. Stiefel's original interests were in topology but his aim was to build an institute where the mathematical implications of computers could be studied :-
Stiefel was quite well-informed about the current state of the art, although he had personally never seen a digital computer. I told him what I had observed in Wilkes's department, I outlined the concept of the von Neumann machine (although this name was not in use at that time), and I was pleased to observe that Stiefel showed considerable interest. He explained that he planned to send two assistants to the United States for a year in order to familiarize themselves with computer technology; after their return, they would build a computer for ETH, since commercially available machines for mathematical purposes did not exist and were not in the foreseeable future.
Speiser completed his electrical engineering degree at ETH in 1948, specialising in low-voltage technology. He then became one of two assistants to Stiefel at the new Institute for Applied Mathematics which was founded in the year Speiser graduated. Stiefel decided that the Institute for Applied Mathematics at ETH should build its own electronic computer, so he sent Heinz Rutishauser and Ambros Speiser on a fact finding visit to the United States in January 1949. Their assignment was to study the state-of-the-art in computing in the United States and then to start a suitable project at the ETH. Rutishauser and Speiser spent most of 1949 at Harvard with Howard Aiken and at Princeton with John von Neumann. They also visited a number of other computer installations, including the ENIAC at Aberdeen, Maryland, and the MARK II at Dahlgren. Returning to the ETH in December 1949, Speiser discovered that plans had changed since Stiefel had managed to persuade the ETH to rent the use of Konrad Zuse's Z4. Accordingly the plan was to put on hold the idea that the ETH would build its own digital computer and first to gain experience installing and working with the Z4. Speiser explains :-
All these specifications of the Z4, as seen in 1949, were very convincing for Stiefel, Rutishauser and Speiser. It must be borne in mind that at this time there were hardly a dozen program-controlled computers in operation, all of them in US. Less than a handful were in use for research in numerical mathematics, the others performed routine calculations. There were no doubts that Z4 could be used for serious mathematical research. ... When the Z4 machine was installed, significant work started almost immediately. Within a few years Zürich rose to be one of the foremost centres in numerical analysis. ... The creative spirit that was ever-present, the continuous expression and evaluation of new ideas, the thoroughly based academic knowledge and the sound scientific judgment were daily realities, I am almost tempted to say: This was the air that we were breathing. I can hardly believe, that Stiefel, when he decided to acquire the Z4, would have dared to hope for success of this degree! The Z4 was also extensively used in education. As early in 1951, we offered to students a course in computer programming with practical exercises on the machine. We believe we were the first on the European continent to do so. This should be taken in consideration by those who often criticize that Swiss Universities were late in recognizing the importance of informatics.
The contract to rent the Z4 was signed by ETH by July 1949 and the computer was operational in Zürich by August 1950. In the same year Speiser married the pianist Margrit Schenk; they had four children. Since becoming Stiefel's assistant, Speiser had been working on his doctorate under Stiefel's supervision. The degree was awarded in 1950 for his thesis Entwurf eines elektronischen Rechengerätes unter besonderer Berücksichtigung der Erfordernis eines minimalen Materialaufwandes bei gegebener mathematischer Leistungsfähigkeit Ⓣ. The thesis was published and reviewed by Herman Goldstine who was a major player in the development of digital computers in the United States. Goldstine writes:-
... the author gives a quite complete account of an electronic digital computer, being considered by the computation laboratory at the Technical Institute in Zürich. The machine is to have a magnetic drum memory of 1200 word capacity, each word being 12 decimal digits. The multiplication speed is 30 ms. and the average access time to the memory is 16 ms. The author gives a comprehensive discussion of all relevant mathematical phases of the problem as he poses it. This is to construct a low cost, rapid machine for a modest size computation laboratory. The machine described is to have about 1000 vacuum tubes and 300 relays.
There followed a series of four papers by Stiefel, Rutishauser and Speiser, Programmgesteuerte digitale Rechengeräte (elektronische Rechenmaschinen) Ⓣ appearing in 1950 and 1951. Herman Goldstine, who also reviewed these papers, writes:-
In this series of papers the authors discuss in very considerable detail a number of the important mathematical questions that naturally arise in the design of a digital computer. These topics include possible number systems, the questions of "fixed" vs "floating" point and complementation, the arithmetic processes, the grouping of numbers to achieve higher than normal precisions, conversion between number systems, the structure of finite approximation methods, error analysis, programming and coding as well as the physical organs of a machine. In many of these considerations the authors have compared the various points of view expressed by others in the field to give a comprehensive picture of the situation as understood at the present time.
In 1952 Speiser habilitated at ERH and was appointed as a privatdozent.
Speiser had been actively working on the project to build a digital computer at ETH from the time he spent the year 1949 in the United States with Rutishauser. Although much work was done with the Z4 at ETH, in parallel Speiser and Rutishauser were working on the construction of ETH's own computer ERMETH (Elektronische Rechenmaschine an der ETH). Speiser was the chief engineer for the project and ERMETH became operational in 1955. While this work was ongoing, a number of interested people visited ETH to see how the work was progressing. These included Walter F Herzog, general manager of IBM Switzerland, and later Arthur L Samuel, research advisor to IBM. After taking a decision to establish a research laboratory in Europe, IBM first tried to site it in England in February 1955 but various conditions were imposed by the English which made this unattractive. Switzerland was their next choice and this proceeded. They decided that their first choice of director was Speiser, but at this stage he was unaware of this decision. Samuel took the unusual step of talking to Speiser's father who was the representative of the canton of Aargau to the Swiss Council of the States or Ständerat as it is called (a role he held from 1948 to 1961). Speiser writes :-
The advice to talk to my father before contacting me was, indeed, unusual. Evidently, Samuel and my father had agreed to keep their meeting confidential -- I learned about it only many years later through a casual remark by my father, but, of course, I did not resent it in the least. But, one point is worth mentioning: When the offer from IBM came in 1955, I almost simultaneously received an offer for employment from a Swiss company that looked quite interesting. I asked my father what he thought about it. He encouraged me to decide for IBM.
Speiser was appointed Director of the IBM research laboratory in Zürich in 1956. At first the laboratory was in a rented building in Adliswil, but in 1961 he persuaded IBM to build a new laboratory at Rüschlikon (close to Zürich). The building was completed near the end of 1962. In the same year Speiser was appointed as Professor at ETH. During his years with IBM he wrote two books:, Impulsschaltungen (Pulse circuits) (1963), and Digitale Rechenanlagen (Digital Calculation Systems) (1965).
By 1965 over 100 people were employed in the laboratory at Rüschlikon :-
By 1966, the laboratory had well-established itself in the new building. Research management did not anticipate further growth, at least for the coming few years.
This seemed to Speiser a good time to move on to another venture :-
In 1966, I decided to make a complete change in my life and to accept the position of Director of Corporate Research of Brown Boveri, a large international corporation based in Switzerland, active mainly in the electric power field. Accordingly, steam turbines and electric generators, rather than computers, became the objects of my daily work.
He worked for this company until he retired in 1987. He died at the age of 81, having suffered a stroke on the previous day.
Speiser received a number of honours for his contributions including election as president of the International Federation for Information Processing from 1965 to 1968. He had been secretary-treasurer of the Federation since 1959. He received an honorary doctorate for his pioneering work in the computer sciences from ETH in 1986. Then, from 1987 to 1993, he was president of the Swiss National Academy of Engineering.
Article by: J J O'Connor and E F Robertson