Speaker
Remigius K Mommsen
(FNAL, Chicago, Illinois, USA)
Description
The CMS event builder assembles events accepted by the first level trigger
and makes them available to the high-level trigger. The event builder needs
to handle a maximum input rate of 100 kHz and an aggregated throughput of
100 GBytes/s originating from approximately 500 sources. This paper presents
the chosen hardware and software architecture. The system consists of 2
stages: an initial pre-assembly reducing the number of fragments by one
order of magnitude and several independent Readout Builder (RU builder)
slices. The RU builder is based on 3 separate services: the buffering of
event fragments during the assembly, the event assembly, and the data flow
manager. A further component is responsible to handle events accepted by the
high-level trigger: the Storage Manager (SM) temporarily stores the events
on disk at a peak rate of 2 GBytes/s until they are permanently archived
offline. In addition, events and data-quality histograms are served by the
SM to online monitoring clients. We discuss the operational experience from
the first months of reading out cosmic ray data with the complete CMS
detector.
Author
Remigius K Mommsen
(FNAL, Chicago, Illinois, USA)
