Tube (BBC Micro)

In computing, the Tube is the expansion interface and architecture of the BBC Microcomputer System which allows the BBC Micro to communicate with a second processor, or coprocessor.

Under the Tube architecture, the coprocessor runs the application software for the user, whilst the Micro (acting as a host) provides all I/O functions, such as screen display, keyboard and storage devices management. A coprocessor unit can be coldplugged into any BBC Micro with a disk interface (whose ROM contained the necessary host software) and used immediately.