NuBus is a 32-bit parallel computer bus, originally developed at MIT and standardized in 1987 as a part of the NuMachine workstation project. The first complete implementation of the NuBus was done by Western Digital for their NuMachine, and for the Lisp Machines Inc. LMI Lambda. The NuBus was later incorporated in Lisp products by Texas Instruments (Explorer), and used as the main expansion bus by Apple Computer and a variant called NeXTBus was developed by NeXT. It is no longer widely used outside the embedded market.
The Macintosh II motherboard, with its six NuBus slots visible on the left
Example of a NuBus graphics card, a Radius PrecisionColor Pro 8/24xj. This is a "half-length" card, with a maximum length of 7 inches (18 cm). The maximum length for full-size NuBus cards is 12 inches (30 cm).
Close-up of the NuBus 90 connectors in a Macintosh Quadra 950
In computer architecture, a bus is a communication system that transfers data between components inside a computer, or between computers. This expression covers all related hardware components and software, including communication protocols.
Four PCI Express bus card slots (from top to second from bottom: ×4, ×16, ×1 and ×16), compared to a 32-bit conventional PCI bus card slot (very bottom)