NuBus is a 32-bit parallel computer bus, originally developed at MIT as a part of the NuMachine workstation project, and eventually used by Apple Computer and NeXT Computer. It is no longer widely used. 32-bit is a term applied to processors, and computer architectures which manipulate the address and data in 32-bit chunks. ... The term Parallel has a number of important meanings: Parallel (geometry) occurs in geometry. ... In computer architecture, a bus is a subsystem that transfers data or power between computer components inside a computer or between computers. ... The Massachusetts Institute of Technology, or MIT, is a research institution and university located in the city of Cambridge, Massachusetts along the Charles River and across from Bostons Back Bay district. ... NuMachine was a project in the late 1970s at MITs Laboratory for Computer Science to design a computer system using microprocessors. ... A computer workstation, often colloquially referred to as workstation, is a high-end general-purpose microcomputer designed to be used by one person at a time and which offers higher performance than normally found in a personal computer, especially with respect to graphics, processing power and the ability to carry... Apple Computer, Inc. ... The NeXT logo, designed by Paul Rand. ...

NuBus architecture

NuBus was a considerable step forward compared to other interfaces of the day. At the time most computer bus systems were 8-bit, as were the computers they plugged into. However NuBus decided on a 32-bit interface because it was clear the market was headed in this direction.

In addition, NuBus was agnostic about the processor itself. Most buses up to this point were basically the pins on the CPU run out onto the backplane, meaning that the cards had to conform to the signalling and data standards of the machine it was plugged into (being little endian for instance). NuBus made no such assumptions, which meant that a NuBus card could be plugged into any NuBus machine, as long as there was an appropriate device driver. This CPU uses numerous pins to connect to the motherboard. ... A backplane is a circuit board (usually a printed circuit board) that connects several connectors in parallel to each other, so that each pin of each connector is linked to the same relative pin of all the other connectors, forming a computer bus. ... When integers or any other data are represented with multiple bytes, there is no unique way of ordering of those bytes in memory or in a transmission over some medium, and so the order is subject to arbitrary convention. ... A device driver, often called a driver for short, is a computer program that enables another program, typically, an operating system (e. ...

And in order to select the proper device driver, NuBus included an ID scheme that allowed the cards to identify themselves to the host computer during startup. This meant that the user didn't have to configure the system, the bane of bus systems up to that point. For instance, with ISA the driver has to be configured not only for the card, but for any memory it needs, the interrupts it uses, and so on. NuBus required no such configuration, making it one of the first examples of plug-and-play architecture. It has been suggested that XT bus architecture be merged into this article or section. ... Plug and Play is a term used in the computer field to describe a computers ability to have new devices, normally peripherals, added to it without having to restart the computer. ...

On the downside, while this flexibility made NuBus much simpler for the user and device driver authors, it made things more difficult for the designers of the cards themselves. Whereas most "simple" bus systems were easily supported with a handful of input/output chips designed to be used with that CPU in mind, with NuBus every card and computer had to convert everything in a platform-agnostic "NuBus world". Typically this meant adding a NuBus controller chip between the bus and any I/O chips on the card, increasing costs. While this is a trivial exercise today, one that all newer buses require, at the time in the 1980s NuBus was considered complex and expensive. This article is about the computer interface. ...

NuBus implementations

NuMachine was never released, but Texas Instruments later took over the NuBus work in 1980 and standardized it as IEEE 1196. This version used a standard 96-pin three-row connector, commonly found on other bus systems like VME and PCI, running the system on a 10 Mhz clock for a maximum burst throughput of 40 MB/s and average speeds of 10 to 20 MB/s. A later addition, NuBus90, bumped the clock rate to 20 MHz for better throughput, burst increasing to about 70 MB/s, and average to about 30 MB/s. Texas Instruments (NYSE: TXN), better known in the electronics industry as TI, is a company based in Dallas, Texas, renowned for developing and commercializing semiconductor and computer technology. ... VME (Virtual Machine Environment) is a mainframe operating system developed by the UK company International Computers Ltd (ICL). ... For other meanings of PCI, see PCI (disambiguation). ...

NuBus was first used in the Texas Instruments Lisp Machine, the TI Explorer, a derivative of the MIT NuMachine design work. Shortly thereafter, in 1986, Texas Instruments used it in the S1500 multiprocessor UNIX system. Lisp machines were general purpose computers designed (often with hardware support) to efficiently run Lisp as their main language. ...

NuBus was later selected by Apple Computer for use in their Macintosh II project, where its plug-n-play nature fit well with the Mac philosophy of ease-of-use. It was used in most of their Mac line through the late 1980s and into the 1990s, and was upgraded to NuBus90 starting with the Macintosh Quadras. Early machines only supported the 20 MHz rate when two cards were talking to each other, the motherboard controller was not upgraded. This was later addressed in the 660av and 840av models, and used on the early PowerMac models. Apple's implementation also supplied an always-on +5v "trickle" power supply for tasks such as watching the phone line while the computer was turned off. This was apparently part of an unapproved NuBus standard. Apple Computer, Inc. ... The box for Mac OS X v10. ...

NuBus was also selected by NeXT Computer for their line of machines, but used a different physical PCB layout. NuBus appears to have seen little use outside these roles, and when Apple switched to PCI in the mid 1990s, NuBus quickly disappeared. The NeXT logo, designed by Paul Rand. ... For other meanings of PCI, see PCI (disambiguation). ...