Willem (aka William) Louis van der Poel

Designer of the ZEBRA computer, van der Poel was a pioneering Dutch computer scientist who also contributed to Algol 68 and co-built a Braille translator. In 1950 he obtained an engineering degree in applied science at Delft University of Technology. In 1956 he obtained his PhD degree from the University of Amsterdam. The title of his PhD thesis was The Logical Principles of Some Simple Computers.

From 1950 until 1967 he worked for the Dutch PTT Nederland, which became KPN (in full Koninklijke KPN N.V., also known as Royal KPN N.V.), a Dutch landline and mobile telecommunications company, including both 2G and 3G mobile operations. From 1962 until 1988 he served as a part-time professor at Delft University of Technology. He was also the first chairman of IFIP Working Group 2.1 on ALGOL, from 1962 to 1968.

Van der Poel is primarily known as a Dutch computer pioneer and designer of Testudo, the PTERA, the ZERO, and the ZEBRA computer. He also contributed to Algol 68 and LISP for the ZEBRA. He is said to be the originator of the Zero One Infinity rule, which suggests that software designs should not impose arbitrary limits on the number of instances of a particular entity: if more than a single instance of it is to be allowed, then the collection size should be without fixed limit.

From 1971 he served as a member of the Royal Netherlands Academy of Arts and Sciences (KNAW). In 1960 he received, together with H. Mol, the Visser-Neerlandia prize for the construction of a Braille translator.