Software bus

A software bus is a software architecture model where a shared communication channel facilitates connections and communication between software modules. This makes software buses conceptually similar to the bus term used in computer hardware for interconnecting pathways.
In the early microcomputer era of the 1970s, Digital Research's operating system CP/M was often described as a "software bus". Lifeboat Associates, an early distributor of CP/M and later of MS-DOS software, had a whole product line named "Software Bus".