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Experiences developing data acquisition system for the BaBar CP violation
experiment located at the Stanford Linear Accelerator Center are presented. The
BaBar detector consists of multiple independent subdetectors joined with a data
acquisition system consisting of a large number of embedded PowerPC single board
computers residing in VME crates. The data acquisition software is layered on the
VxWorks real-time operating system. It is partitionable to allow subsystems (as well
as test stands) to operate independently. Data is assimilated into events through a
combination of shared memory and a high performance network. This system
presents data to a UNIX farm via a high speed non-blocking ethernet switch at a rate
of 2 KHz.
Topics such as bootstrapping and loading 200 processors, NFS file access for these
processors and software development and deployment are discussed.
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