Many people, not only at CERN but also throughout the world, were saddened to learn that their friend and colleague David Williams had died from cancer on 24 October.

David came to CERN from the University of Cambridge in 1966, with a degree in physics and a Masters in computer science. At the time he was one of the few people in the laboratory with formal computer training, as opposed to the physicists who learned on the job. These were very early, if not pioneering, days for computer-science courses, and Cambridge was among the front-runners in the subject.

Joining what was called the Documents and Data (DD) Division, David worked first on software for analysing bubble-chamber photographs. He subsequently led the group that supported experiments with hybrids of bubble chambers and electronic detectors, and then the group supporting online computing in experiments. He thus witnessed the enormous changes that took place in particle physics as the era of bubble chambers came to an end and the powerful, compact mini-computers revolutionized the data collection.

Armed with this experience, David moved on to become deputy leader of DD in 1985 and then leader of the re-named Computing and Networks Division in 1989, the year that the Large Electron–Positron Collider started up. He held this position until 1996, when the member states approved the Large Hadron Collider and its experiments.

This was the period of transition from central mainframes and supercomputers to a completely distributed computing environment for the acquistion, processing management and analysis of the hundreds of terabytes of data produced by CERN experiments and to a reasonably coherent desktop environment for the more than 10,000 staff and researchers worldwide who use CERN's computing facilities.

It was also the period in the division when Tim Berners-Lee and collaborators, with David's strong support, created the World Wide Web. As division leader, David had the foresight to encourage studies that ultimately led to the programming paradigm shift from Fortran to C++.

The period 1996–7 was a time of change for David. He actively fostered the development of the Internet in Europe, not just as a tool for scientific research but also as a motor for Europe's overall economic development.

This naturally led to his holding a number of positions at national and European level. He was president of the Trans-European Research and Education Networking Association (TERENA) from 1999 to 2003, making a pioneering contribution through the Study into European Research and Education Networking as Targeted by e-Europe (SERENATE) study and developing a strategic vision of the future of research and education networking.

He was also a member of various UK committees dealing with e-science and was chair of the e-Science Advisory Board of the UK's Council for the Central Laboratory of the Research Councils.

With this broad view, coupled with his energy and managerial talents, it was natural that David moved on at CERN to be responsible for the overall coordination of CERN's relations with the European Union, a post he held until the end. He played a highly significant role in formulating and obtaining European Commission support for the European part of the LHC worldwide computing environment, which is now almost ready for the LHC start-up in 2007. He was able to persuade the Commission to admit CERN to the Framework Programme (FP), and helped to formulate and organize the FP5 and FP6 projects European DataGrid and Enabling Grids for E-sciencE in Europe.

For those who knew him, David was always a private person, unwilling to talk about himself or worry others with his problems. However, the well merited award in 2005 of an honorary professorship at Edinburgh University was a source of enormous personal satisfaction to him. Many people will remember him as being generous and supportive, always ready to spring to the defence of someone who he considered to be wrongly criticized. He also had the habit, when attending scientific talks, to ask the questions that others were afraid to ask. Although David had usually understood perfectly, this gave the speaker the opportunity to clarify points that had previously been somewhat obscure.

Much sympathy goes out in this difficult time to David's wife Lidy, to his children, Mark and Marietta, and their families.