at&t's unix system development laboratory (usdl) was succeeded by at&t information systems (attis), which distributed unix system v, release 3, in 1987. svr3 included streams, remote file sharing (rfs), the file system switch (fss) virtual file system mechanism, a restricted form of shared libraries, and the transport layer interface (tli) network api. the final version was release 3.2 in 1988, which added binary compatibility to xenix on intel platforms (see intel binary compatibility standard).