Speaker
Dr
M. Steinke
(Ruhr Universitaet Bochum)
Description
In the past year, BaBar has shifted from using Objectivity to using ROOT I/O
as the basis for our primary event store. This shift required a total
reworking of Kanga, our ROOT-based data storage format. We took advantage
of this opportunity to ease the use of the data by supporting multiple
access modes that make use of many of the analysis tools available in
ROOT.
Specifically, our new event store supports: 1) the pre-existing separated
transient + persistent model, 2) a transient based load-on-demand model
currently being developed, 3) direct access to persistent data classes in
compiled code, 4) fully interactive access to persistent data classes from
either the ROOT prompt and via interpreted macros.
We will describe key features of Kanga including: 1) the separation and
management of transient and persistent representations of data, 2) the
implementation of read on demand references in ROOT, 3) the modular and
extensible persistent event design, 4) the implementation of schema
evolution and 5) BaBar specific extensions to core ROOT classes that we
used to preserve the end-user "feel" of ROOT.
Author
Dr
M. Steinke
(Ruhr Universitaet Bochum)
