Traditional hierarchical file-systems tend to impose a burden, for example when a sub-directory layout is contradicting a user's perception of where files would be stored.
Having a tag-based interface alleviates this hierarchy problem and enables users to query for data in an intuitive fashion.
Semantic file systems raise technical design challenges as indexes of words, tags or elementary signs of some sort have to be created and constantly updated, maintained and cached for performance to offer the desired random, multi-variate access to files in addition to the underlying, mostly traditional block-based filesystem.
The notion of semantic file system was proposed in 1991 by researchers of the MIT and École des Mines de Paris.
Gifford et al.[1] suggested the idea of file type-specific metadata automatically extracted by a file-type specific transducer.