A mass storage system was also developed in parallel with NLTSS that used the LINCS protocols (same file and directory protocols as NLTSS). This system/software was later commercialized as the Unitree product. Unitree was generally superseded by the High Performance Storage System (HPSS) that could loosely be considered a legacy of LINCS and NLTSS. For example, LINCS and NLTSS introduced a form of third party transfer (to copy file to file in NLTSS a process could send two requests to file servers, one to read and one to write and direct the file servers to transfer the data between themselves) that carried through in modified form to Unitree and HPSS.