21–27 Mar 2009
Prague
Europe/Prague timezone

Architecture of the CMS Data Acquisition System

26 Mar 2009, 08:00
1h
Prague

Prague

Prague Congress Centre 5. května 65, 140 00 Prague 4, Czech Republic
Board: Thursday 099
poster Online Computing Poster session

Speaker

Dr Vivian ODell (FNAL)

Description

The CMS event builder assembles events accepted by the first level trigger and makes them available to the high-level trigger. The system 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 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 compresses and stores the events on disk at a peak rate of 2 GBytes/s and makes them available for offline processing. In addition, events and data-quality histograms are served to online monitoring clients. We discuss the operational experience from the first months of reading out the complete CMS detector.

Primary author

Dr Vivian ODell (FNAL)

Presentation materials

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