A hardware and/or software search facility for searching and retrieving data stored on a mobile device. An index to the data is stored in fast memory (e.g., RAM) on the mobile device. The index contains a minimal amount of information necessary to present search results to a user. A supplemental data file is stored in storage that is local to or remote from the mobile device. The supplemental data files contain additional organized data that may be used to enhance the search results. In response to a search query, the facility uses the index to identify results that are responsive to the search query. The results are presented by the facility in accordance with predetermined rules. The facility may use the supplemental data file to perform further processing and present additional information. In some embodiments, the facility may mount or unmount indices and supplemental files from a device.