LHC Computing: past, present and future

Abstract

Although the LHC experiments have been designed and prepared since 1984, the challenge of LHC computing was only tackled seriously much later, at the end of the ‘90s. This was the time at which the Grid paradigm wasemerging, and LHC computing had great hopes that most of its challenges would be solved by this new paradigm. The path to having functional and efficient distributed computing systems was in the end much more complex than anticipated. However, most obstacles were overcome, thanks to the introductionof new paradigms and a lot of manpower investment from the experiments and from the supporting IT units (for middleware development and infrastructuresetup). This contribution is briefly outlining some of the biggest hopes and disillusions of these past 20 years, and gives a brief outlook to the coming trends.