TCP/IP is the network protocol, along with the routing protocol BGP that make up the Internet. Because of the rise in popularity of the Internet, TCP/IP is the most popular networking protocol of all time. There simply is an amazing amount of OS's and platforms that support TCP/IP.
The most popular implementation of TCP/IP came from the 4.3 BSD release, because of the BSD copyright, people were free to adapt the software to their own needs.
Vint Cerf is largely credited with creating the protocol.
TCP/IP is a family of several protocols.
Lower OSI protocols
Address resolution protocol.
Serial line protocl.
Point to point protocol.
Higher OSI protocols
Transmission control protocol
User datagram protocol
Historical Systems Including TCP/IP
This list is far, far from exhaustive, and primarily meant for systems from the 1980s, before TCP/IP became universal on all but embedded systems.
- BSD Unix from 4.2 onward.