LCIO - A persistency framework for linear collider simulation studies

Almost all groups involved in linear collider detector studies have their own simulation software framework. Using a common persistency scheme would allow to easily share results and compare reconstruction algorithms. We present such a persistency framework, called LCIO (Linear Collider I/O). The framework has to fulfill the requirements of the different groups today and be flexible enough to be adapted to future needs. To that end we define an ''abstract object persistency layer'' that will be used by the applications. A first implementation, based on a sequential file format (SIO) is completely separated from the interface, thus allowing support to additional formats if necessary. The interface is defined with the AID (Abstract Interface Definition) tool from freehep.org that allows creation of Java and C++ code synchronously. In order to make use of legacy software a Fortran interface is also provided. We present the design and implementation of LCIO.