NuBus

NuBus (pronounced ‘New Bus’) is a 32-bit , originally developed at the and standardized by the Institute of Electrical and Electronics Engineers in 1987.
==History==
The first implementation of NuBus dates back to the 1970s with 's project, and ' LMI Lambda.Steve Ward | CSAILWestern Digital Corp. Company History The NuMachine and Lisp projects were acquired by in 1983.The Explorer III Project (historical) The NuBus technology was then incorporated their own family of Lisp computers.Irvine-Based NuMachine to Close by June, Los Angeles Times. 1985-03-12
NuBus was also used as the main by Apple Computer and NeXT from the late 1980s to the mid 1990s. It is no longer widely used outside of the embedded market and was withdrawn by IEEE on March 6, 2000.
==Implementations==
The first NuBus standard, also known as NuBus 87, was approved on June 11, 1987 as IEEE 1196-1987. This version used a standard 96-pin three-row Euro-DIN connector, 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. The first Apple model to use this implementation was the Macintosh II.
A proposed revision, NuBus 90, also known as IEEE P1196-R1990, increased the clock rate to 20 MHz, with burst throughput increasing to about 70 MB/s, and averaging about 30 MB/s. It also implemented a +5 V trickle charge for detecting modem signals while powered down. However, this spec was not formally approved as of November 12, 1991. The Macintosh Quadra series used a partial implementation in which NuBus 90 cards could communicate with one another at 20 MHz, but still used an older controller that communicated with the motherboard itself at 10 MHz. The Quadra AV and early Power Macintosh series used the full NuBus 90 implementation. By the time 2nd generation Power Macintosh models were released, Apple had switched to the PCI standard.
NeXT developed its own variant of the standard called NeXTbus, which used a different physical layout. The bus was clocked at 25 MHz, with burst throughput up to 100 MB/s. Communication between NeXTbus cards required a NeXTbus Interface Chip (NBIC), which was an option in the original NeXT Computer and included with all 68040-based NeXTcubes.
==References==
==See also==
*A/ROSE
*Processor direct slot
==External links==
*IEEE 1196-1987 at Institute of Electrical and Electronics Engineers Standards Association
*Technical Note HW520: NuBus Expansion Interface Q&As by Apple Computer (1990-10-01, mirrored)
**HW15: NuBus Block Transfer Modes Resource Entries (1991-02-01, mirrored)
**HW16: NuBus Interrupt Latency (I Was a Teenage DMA Junkie) (1988-12-01, mirrored)
**HW17: NuBus Physical Designs - Beware (1989-06-01, mirrored)
**HW18: NuBus Power Allocation (1989-10-01, mirrored)
**HW21: +5 Volt Trickle (1993-04-01, mirrored)
*NeXTbus Device Drivers by NeXT Computer (1995, mirrored)
**NextBus Interface Chip Specification (PDF, 1990)
*Apple Computer NUbus connector pinout at InterfaceBus.com
*Developing for the Macintosh NuBus (PDF) by B.G. Taylor at CERN (1989-09)
*So, anyone want to relate to me the tragic history of NuBus? at Ars Technica (2001-08-27)
*Nubus at Applefritter
*NuBus (87) and NuBus 90 at HardwareBook
*NuBus and earlier video cards at Herb's Mac cards
*NuBus and NuBus 90 pinout at Pinouts.ru
*NuBus at PC Magazine
*NeXTbus at the NeXT Wiki
*Nubus at Techopedia
*Nu Bus at the WikiWikiWeb
* at Wikipedia
Category:Components
Category:IEEE standards