Abstract: In order to satisfy the request of naturality and efficiency of managing unstructured personal information in mobile environment,we present a mobile-based personal information management(PIM) system called-Ruby.First,we analyze users' demand for a typical mobile PIM system and describe the architecture of the system.Then we introduce its interface and interaction process,and present two searching key supporting techniques:unstructured note taking and ink-tag based searching.Finally,our evaluation shows that the system is well accepted by the users.