DECnet

DECnet is a proprietary suite of network protocols created by Digital Equipment Corporation, originally released in 1975 in order to connect two PDP-11 minicomputers. It evolved into one of the first peer-to-peer network architectures, thus making DEC into a networking powerhouse in the 1980s.

From a technical standpoint DECnet was built right into the DEC flagship operating system (VAX/VMS), being the foundation for the first cluster architecture ever designed, the VAXcluster[?].

Initially built with four layers it later (1992) evolved into a seven layer OSI compliant networking protocol, around the time when open systems (POSIX compliant, i.e. UNIX-like) were grabbing marketshare from the proprietary OSes like VAX/VMS and AlphaVMS.

It has been ported to UNIX (Ultrix), PCs and Macs (DEC Pathworks) transforming these into DECnet end-nodes on a network of VAXes.