SunOS Networking
Peter Hurley, John A. Mariani, Nick Nei, Jim Rudolf · 1992
The needs of the Advanced Research Projects Agency (ARPA) community and the desire to access the ARPA Internet network steered the development of sockets on Berkeley UNIX in the network-pioneering days of the early 1980s. At that time, the only standard interprocess-communication facility in UNIX was the pipe, and although it provided a reliable and sequenced flow of data between related processes, it lacked the support for processes on different machines to communicate over networks. Sockets enabled this. Using sockets the machines can exchange messages bidirectionally, they do not have to coexist on the same system and processes do not have to share a common ancestor.