Prof. Jesus Marco (IFCA (CSIC-UC) Santander Spain)
The strategy at the end of the LEP era for the long term preservation of physics results and data processing framework was not obvious. One of the possibilities analyzed at the time, previously to the generalization of virtualization techniques, was the setup of a dedicated farm, to be conserved in its original state for medium-long term, at least until the new data from LHC could indicate the need to reanalyze LEP data, the most significant example being the Higgs boson search. Such an infrastructure was setup at IFCA in 2001, including 80 equal servers where the software of the DELPHI experiment was installed and tested, and analysis ntuples and code were stored. This set of servers have been periodically restarted and tested, to examine the feasibility of this approach for complete preservation, and allow a detailed comparison with the approach based on the use of virtual machines. In parallel, all DELPHI data at DST (Data Summary Tapes) level were copied to IFCA and stored in tape in LTO-1 format. The latest results at LHC indicate that there will be likely no need to reanalyze LEP data. This contribution describes this experience, the results obtained after more than 10 years of "freezing", and concludes with the lessons learnt in this cycle across two generation of experiments.
Mr Rafael Marco De Lucas (IFCA (CSIC-UC) Santander SPAIN)