The STAR Analysis Framework Component Software in a Real-World Physics Experiment

Paper: 322
Session: A (talk)
Speaker: Tull, Craig, Ernest Orlando Lawrence Berkeley National Laboratory (LBL), Berkeley
Keywords: mixed language programming, object-oriented methods, component software, CORBA, dynamic programming

The STAR Analysis Framework
Component Software in a Real-World Physics Experiment

C.Tull, W.Greiman, D.Olson, D.Prindle, H.Ward

Ernest Orlando Lawrence Berkeley National Laboratory
University of Washington, Nuclear Physics Laboratory GL-10

for the Solenoidal Tracker At RHIC Collaboration


The Solenoidal Tracker At RHIC (STAR) collaboration is a large international
collaboration of almost 400 high-energy and nuclear physicists located at 37
institutions in Brazil, Croatia, Germany, Israel, Poland, Russia, and the
United States. When the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven
National Laboratory (BNL), Upton, NY, USA comes on line in 1999, STAR will
begin data taking and concurrent data analysis that is expected to last until
the year 2010.

During normal operation, the STAR collaboration expects a data acquisition
rate of approximately 250 TBytes of raw data per year for the ten-year operat-
ing lifetime of RHIC. Factoring in Data Summary Tapes (DSTs) derived from the
raw data and anticipating comparable statistics from Monte Carlo simulations
yields a total data volume of approximately 1 PByte per year that STAR must
manage, process, and analyze.

Due to its size and geographical distribution, its data volume, and its long
lifetime, STAR faces many of the same software and computer challenges that
the next generation of high-energy physics experiments will be facing at fa-
cilities such as LHC at CERN starting in 2004.

The STAR Analysis Framework (STAF) is a major part of the software solution
that has been, and is being developed by the Software Infrastructure (SOFI)
group within the STAR collaboration.

STAF is a highly modular framework written (largely) in C++ and designed
around a CORBA-compliant software bus package. STAF provides a CORBA-compli-
ant encapsulation of data analysis algorithms written in FORTRAN, C, and C++
which allows the seamless integration of physics software components and sys-
tem-like software components controlled at run time by a high-level scripting
language and/or by Graphical User Interfaces.

STAF has been in widespread use within STAR since June of 1996 for a variety
of simulation and analysis tasks. The Time Projection Chamber (TPC) system
tests being conducted at the Ernest Orlando Lawrence Berkeley National
Laboratory (Berkeley Lab) is making especially heavy use of the network I/O
features of STAF by writing data to the network using the XDR-based Dataset
Format (XDF), part of the Dataset I/O component of STAF.

We present in this paper our experience with the STAR Analysis Framework
specifically, and with the software-bus/component approach to software engi-
neering in a physics experiment in general. We also discuss our choices of
communication and interface protocols and the importance of designing these
protocol layers in a manner which allows for "graceful retirement" of said
protocols as a means of prolonging the effective lifetime of software systems.

In addition, we are in the process of investigating and testing alternatives
for our high-level scripting language and user interface, and for our final
distributed software bus technology. We will present the latest status of our
investigations and tests into these alternatives.