SND off-line framework

SND is a spherical non-magnetic detector operating since 1996 at VEPP-2M electron-positron collider in Novosibirsk. SND is performing an upgrade of its subsystems, electronics, and software for the next run at VEPP-2000. Present Fortran-based offline programs will be replaced with the object-oriented framework, which supports simulation, reconstruction and analysis activities. New framework exploits the experience obtained in the work with the current offline and supports or extends its essential features. The main framework concept is a module, which is a basic processing unit consuming some data and producing new data. Every module can be parameterized during run time. Formalized description of the modules is used by the framework sequencer for the selection and ordering of minimal subset of modules for any given task. Data persistency services are made sufficiently abstract to allow implementation for different persistency technologies. Presently there is an implementation for the sequential files with packed data. The framework provides an interface for scripting languages. Together with a custom expression parser this gives a support for extensible run-time histogramming, The functional prototype of the framework was implemented in Python language and proved the concepts of the project. Currently this prototype is being reimplemented in C++.