Apple's metadata filesystem - stores file metadata in seperate database, import for common and customized file metadata, sophisticated api and command line query
Wasabi is an effort to create a unified searching and metadata storage specification for the free desktop. This document contains draft specs meant for further discussion.
R. Amorim, J. Castro, J. da Silva, and C. Ribeiro. New Contributions in Information Systems and Technologies, page 101--111. Springer International Publishing, (2015)
R. Beale. SIGDOC '05: Proceedings of the 23rd annual international conference on Design of communication, page 48--53. New York, NY, USA, ACM Press, (2005)
R. Beale. SIGDOC '05: Proceedings of the 23rd annual international conference on Design of communication, page 48--53. New York, NY, USA, ACM Press, (2005)