(WINdows Future Storage) The code name for a unified storage subsystem that was expected in Windows Vista but never completed. Using a relational database and XML meta-data, WinFS was designed to go beyond the hierarchical view that Explorer presents to the user. It would have let users index and combine heterogeneous data formats such as files, folders, e-mail and contacts. Data would be searched like a search engine, which yields results in different formats (HTML pages, documents, etc.). FS Is Not a File System Because "FS" is in the name, WinFS was often mistaken for a new file system. WinFS was designed to sit on top of the NTFS file system, and software developers would write to the WinFS programming interface (API). See NTFS.