Data analysis software tools used during VIRGO engineering runs, review and future needs

During last years, data flow and data storage needs for large gravitational waves interferometric detectors have reached an order of magnitude similar to those of high energy physics experiments. Software tools have been developed to handle and analyze these large amounts of data, with the specificities associated to gravitational waves search. We will make a review of the experience acquired during engineering runs on the VIRGO detector with the currently used data analysis software tools, pointing out the peculiarities inherent to our type of experiments. We will also show what are the possible future needs for the offline analysis VIRGO data.