NuBus is a 32-bit alongside computer bus, originally developed at MIT as a allotment of the NuMachine workstation project.1 The aboriginal complete accomplishing of the NuBus and the NuMachine was done by Western Digital for their NuMachine, and for the Lisp Machines Inc. LMI-Lambda. The NuBus was after congenital in articles by Texas Instruments (Explorer), Apple Computer and NeXT. It is no best broadly acclimated alfresco of the anchored market.
Sunday, February 5, 2012
Architecture
NuBus was a ample footfall advanced compared to added interfaces of the day. At the time a lot of computer bus systems were 8-bit, as were the computers they acquainted into. However, NuBus absitively on a 32-bit interface because it was bright the bazaar was headed in that direction.
In addition, NuBus was doubter about the processor itself. A lot of buses up to this point were basically the pins on the CPU run out assimilate the backplane, acceptation that the cards had to accommodate to the signalling and abstracts standards of the apparatus they were acquainted into (being little endian for instance). NuBus fabricated no such assumptions, which meant that a NuBus agenda could be acquainted into any NuBus machine, as continued as there was an adapted accessory driver.
In addition, NuBus was doubter about the processor itself. A lot of buses up to this point were basically the pins on the CPU run out assimilate the backplane, acceptation that the cards had to accommodate to the signalling and abstracts standards of the apparatus they were acquainted into (being little endian for instance). NuBus fabricated no such assumptions, which meant that a NuBus agenda could be acquainted into any NuBus machine, as continued as there was an adapted accessory driver.
input/output
In adjustment to baddest the able accessory driver, NuBus included an ID arrangement that accustomed the cards to analyze themselves to the host computer during startup. This meant that the user didn't accept to configure the system, the affliction of bus systems up to that point. For instance, with ISA the disciplinarian had to be configured not alone for the card, but for any anamnesis it required, the interrupts it used, and so on. NuBus appropriate no such configuration, authoritative it one of the aboriginal examples of plug-and-play architecture.
On the downside, while this adaptability fabricated NuBus abundant simpler for the user and accessory disciplinarian authors, it fabricated things added difficult for the designers of the cards themselves. Whereas a lot of "simple" bus systems were calmly accurate with a scattering of input/output chips advised to be acclimated with that CPU in mind, with NuBus every agenda and computer had to catechumen aggregate in a platform-agnostic "NuBus world". Typically this meant abacus a NuBus ambassador dent amid the bus and any I/O chips on the card, accretion costs. While this is a atomic exercise today, one that all newer buses require, at the time in the 1980s NuBus was advised circuitous and expensive.
On the downside, while this adaptability fabricated NuBus abundant simpler for the user and accessory disciplinarian authors, it fabricated things added difficult for the designers of the cards themselves. Whereas a lot of "simple" bus systems were calmly accurate with a scattering of input/output chips advised to be acclimated with that CPU in mind, with NuBus every agenda and computer had to catechumen aggregate in a platform-agnostic "NuBus world". Typically this meant abacus a NuBus ambassador dent amid the bus and any I/O chips on the card, accretion costs. While this is a atomic exercise today, one that all newer buses require, at the time in the 1980s NuBus was advised circuitous and expensive.
Implementations
The NuBus became a accepted in 1987 as IEEE 1196. This adaptation acclimated a accepted 96-pin three-row connector, active the arrangement on a 10 MHz alarm for a best access throughput of 40 MB/s and boilerplate speeds of 10 to 20 MB/s. A after addition, NuBus90, added the alarm amount to 20 MHz for bigger throughput, access accretion to about 70 MB/s, and boilerplate to about 30 MB/s.
The NuBus was aboriginal developed commercially in the Western Digital NuMachine, and aboriginal acclimated in a assembly artefact by their licensee, Lisp Machines, Inc., in the LMI-Lambda, a Lisp Machine. The activity and the development accumulation was awash by Western Digital to Texas Instruments in 1984. The technology was congenital into their TI Explorer, aswell a Lisp Machine. In 1986, Texas Instruments acclimated the NuBus in the S1500 multiprocessor UNIX system. Later, both Texas Instruments and Symbolics developed Lisp Machine NuBus boards (the TI MicroExplorer and the Symbolics MacIvory) based on their Lisp acknowledging microprocessors. These NuBus boards were co-processor Lisp Machines for the Apple Macintosh band (the Mac II and Mac Quadras).
The NuBus was aboriginal developed commercially in the Western Digital NuMachine, and aboriginal acclimated in a assembly artefact by their licensee, Lisp Machines, Inc., in the LMI-Lambda, a Lisp Machine. The activity and the development accumulation was awash by Western Digital to Texas Instruments in 1984. The technology was congenital into their TI Explorer, aswell a Lisp Machine. In 1986, Texas Instruments acclimated the NuBus in the S1500 multiprocessor UNIX system. Later, both Texas Instruments and Symbolics developed Lisp Machine NuBus boards (the TI MicroExplorer and the Symbolics MacIvory) based on their Lisp acknowledging microprocessors. These NuBus boards were co-processor Lisp Machines for the Apple Macintosh band (the Mac II and Mac Quadras).
Macintosh II
NuBus was after called by Apple Computer for use in their Macintosh II project, area its plug-n-play attributes fit able-bodied with the Mac aesthetics of ease-of-use.2 It was acclimated in a lot of of the Macintosh II alternation and Macintosh Quadras that fabricated up the professional-level Mac calendar from the backward 1980s into the mid-1990s, and was upgraded to NuBus90 starting with the Macintosh Quadras. Aboriginal Quadras alone accurate the 20 MHz amount if two cards were talking to anniversary other, aback the motherboard ambassador was not upgraded. This was after addressed in the 660AV and 840AV models, and acclimated on the aboriginal PowerMac models. After PowerMacs adopted Intel's PCI bus. Apple's NuBus accomplishing acclimated pin and atrium connectors with thumbscrews on the aback of the agenda rather than the generally adamant bend connectors with Phillips screws central the case that a lot of cards use, authoritative it abundant easier to install cards. Apple's computers aswell supplied an always-on +5 V "trickle" ability accumulation for tasks such as watching the buzz band while the computer was angry off. This was allegedly allotment of an crooked NuBus standard.
NuBus was aswell called by NeXT Computer for their band of machines, but acclimated a altered concrete PCB layout. NuBus appears to accept apparent little use alfresco these roles, and if Apple switched to PCI in the mid 1990s, NuBus bound disappeared
NuBus was aswell called by NeXT Computer for their band of machines, but acclimated a altered concrete PCB layout. NuBus appears to accept apparent little use alfresco these roles, and if Apple switched to PCI in the mid 1990s, NuBus bound disappeared
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