A schematic view of architecture design for PET-Tool. PET-Tool has four functional modules, Extractor, Examiner, Mapper, and ProjectManager. Extractor uploads sequence files and dissects the PET sequences from raw sequences. Examiner provides analytical functions for users to evaluate the extraction results and PET sequence quality. Mapper searches the genome database for the mapping locations of the PET sequences. ProjectManager is a hierarchical information management system. 'P' stands for "project". 'CSA' stands for "compressed suffix array", which in this instance is derived from the human genome assembly hg17.