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32-418: Early microcomputer buses like S-100 were often just connections to the pins of the microprocessor and to the power rails. This meant that a change in the computer's architecture generally led to a new bus as well. Looking to avoid such problems in the future, NuBus was designed to be independent of the processor, its general architecture and any details of its I/O handling. Among its many advanced features for

64-605: A personal computer that was designed, manufactured and sold by Apple Computer from March 1994 to January 1996. It is the mid-range machine of the first generation of Power Macintosh line, between the Power Macintosh 6100 and the 8100 . The 7100 re-used the Macintosh IIvx case with few changes. The initial version of the 7100 was powered by a 66 MHz PowerPC 601 , and an 80 MHz version replaced it in January 1995. The 7100

96-479: A 32-bit address bus , permitting up to 4 GB of RAM to be accessed, far more than previous generations of system architecture allowed. 32-bit designs have been used since the earliest days of electronic computing, in experimental systems and then in large mainframe and minicomputer systems. The first hybrid 16/32-bit microprocessor , the Motorola 68000 , was introduced in the late 1970s and used in systems such as

128-467: A mirror surface. HDR imagery allows for the reflection of highlights that can still be seen as bright white areas, instead of dull grey shapes. A 32-bit file format is a binary file format for which each elementary information is defined on 32 bits (or 4 bytes ). An example of such a format is the Enhanced Metafile Format . Power Macintosh 7100 The Power Macintosh 7100 is

160-413: A total of 96 bits per pixel. 32-bit-per-channel images are used to represent values brighter than what sRGB color space allows (brighter than white); these values can then be used to more accurately retain bright highlights when either lowering the exposure of the image or when it is seen through a dark filter or dull reflection. For example, a reflection in an oil slick is only a fraction of that seen in

192-402: Is a 32-bit machine, with 32-bit registers and instructions that manipulate 32-bit quantities, but the external address bus is 36 bits wide, giving a larger address space than 4 GB, and the external data bus is 64 bits wide, primarily in order to permit a more efficient prefetch of instructions and data. Prominent 32-bit instruction set architectures used in general-purpose computing include

224-581: Is that a processor with 32-bit memory addresses can directly access at most 4  GiB of byte-addressable memory (though in practice the limit may be lower). The world's first stored-program electronic computer , the Manchester Baby , used a 32-bit architecture in 1948, although it was only a proof of concept and had little practical capacity. It held only 32 32-bit words of RAM on a Williams tube , and had no addition operation, only subtraction. Memory, as well as other digital circuits and wiring,

256-606: The 8088/8086 or 80286 , 16-bit microprocessors with a segmented address space where programs had to switch between segments to reach more than 64 kilobytes of code or data. As this is quite time-consuming in comparison to other machine operations, the performance may suffer. Furthermore, programming with segments tend to become complicated; special far and near keywords or memory models had to be used (with care), not only in assembly language but also in high level languages such as Pascal , compiled BASIC , Fortran , C , etc. The 80386 and its successors fully support

288-743: The IBM System/360 , IBM System/370 (which had 24-bit addressing), System/370-XA , ESA/370 , and ESA/390 (which had 31-bit addressing), the DEC VAX , the NS320xx , the Motorola 68000 family (the first two models of which had 24-bit addressing), the Intel IA-32 32-bit version of the x86 architecture, and the 32-bit versions of the ARM , SPARC , MIPS , PowerPC and PA-RISC architectures. 32-bit instruction set architectures used for embedded computing include

320-536: The IBM System/360 Model 30 had an 8-bit ALU, 8-bit internal data paths, and an 8-bit path to memory, and the original Motorola 68000 had a 16-bit data ALU and a 16-bit external data bus, but had 32-bit registers and a 32-bit oriented instruction set. The 68000 design was sometimes referred to as 16/32-bit . However, the opposite is often true for newer 32-bit designs. For example, the Pentium Pro processor

352-533: The 16-bit segments of the 80286 but also segments for 32-bit address offsets (using the new 32-bit width of the main registers). If the base address of all 32-bit segments is set to 0, and segment registers are not used explicitly, the segmentation can be forgotten and the processor appears as having a simple linear 32-bit address space. Operating systems like Windows or OS/2 provide the possibility to run 16-bit (segmented) programs as well as 32-bit programs. The former possibility exists for backward compatibility and

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384-423: The 68000 family and ColdFire , x86, ARM, MIPS, PowerPC, and Infineon TriCore architectures. On the x86 architecture , a 32-bit application normally means software that typically (not necessarily) uses the 32-bit linear address space (or flat memory model ) possible with the 80386 and later chips. In this context, the term came about because DOS , Microsoft Windows and OS/2 were originally written for

416-468: The 7100 as they had for some contemporary Macintosh Quadra models, opting instead to offer the 7100 bundled with the SoftWindows emulator at a price of $ 385. With an optional 256KB L2 cache card installed, MacWorld Magazine determined that the performance is comparable to 25 MHz Intel 80486SX . Introduced March 14, 1994: Introduced January 3, 1995: The Power Macintosh 7100's internal code name

448-490: 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, in the 1980s NuBus was considered needlessly complex and expensive. The NuBus became an IEEE standard in 1987 as IEEE 1196 . This version used a standard DIN 41612 96-pin three-row 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. A later addition, NuBus 90 , increased

480-489: The case that most cards use, making it much easier to install cards. Apple's computers also supplied an always-on +5 V "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. 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

512-549: The clock rate to 20 MHz for better throughput, burst increasing to about 70 MB/s, and average to about 30 MB/s. The NuBus was first developed commercially in the Western Digital NuMachine , and first used in a production product by their licensee, Lisp Machines, Inc. , in the LMI-Lambda, a Lisp Machine . The project and the development group was sold by Western Digital to Texas Instruments in 1984. The technology

544-415: The codename did not officially link to his intellectual property and identity. After they reportedly refused, he wrote a letter to the editor that appeared in a 1994 issue of MacWeek , seeking to inform their readers of the situation. Following the letter, a rogue programmer at Apple renamed the project to " BHA " (for Butt-Head Astronomer ). Sagan then sued Apple for libel over the new name, but since

576-417: The era, NuBus used a 32-bit backplane when 8- or 16-bit busses were common. This was seen as making the bus "future-proof", as it was generally believed that 32-bit systems would arrive in the near future while 64-bit buses and beyond would remain impractical and excessive. In addition, NuBus was agnostic about the processor itself. Most buses up to this point conformed to the signalling and data standards of

608-412: The latter is usually meant to be used for new software development . In digital images/pictures, 32-bit usually refers to RGBA color space ; that is, 24-bit truecolor images with an additional 8-bit alpha channel . Other image formats also specify 32 bits per pixel, such as RGBE . In digital images, 32-bit sometimes refers to high-dynamic-range imaging (HDR) formats that use 32 bits per channel,

640-411: The machine they were plugged into (being big or little endian for instance). NuBus made no such assumptions, which meant that any NuBus card could be plugged into any NuBus machine, as long as there was an appropriate device driver . 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

672-422: The mid-1990s, NuBus quickly disappeared. 32-bit In computer architecture , 32-bit computing refers to computer systems with a processor , memory , and other major system components that operate on data in 32- bit units. Compared to smaller bit widths, 32-bit computers can perform large calculations more efficiently and process more data per clock cycle. Typical 32-bit personal computers also have

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704-612: The mid-2000s with installed memory often exceeding the 32-bit 4G RAM address limits on entry level computers. The latest generation of smartphones have also switched to 64 bits. A 32-bit register can store 2 different values. The range of integer values that can be stored in 32 bits depends on the integer representation used. With the two most common representations, the range is 0 through 4,294,967,295 (2 − 1) for representation as an ( unsigned ) binary number , and −2,147,483,648 (−2 ) through 2,147,483,647 (2 − 1) for representation as two's complement . One important consequence

736-489: The motherboard controller was not upgraded. This was later addressed in the NuBus implementation on the 660AV and 840AV models. This improved NuBus controller was used in the first generation Power Macintosh 6100 , 7100 and 8100 models. Later Power Mac models adopted Intel 's PCI bus. Apple's NuBus implementation used pin and socket connectors on the back of the card rather than edge connectors with Phillips screws inside

768-463: The new codename was a expression of opinion, not fact, he lost his case. Sagan continued pursuing lawsuits. When he sued Apple again, this time for the original use of his name, he lost this suit as well. Sagan and Apple, apparently not wishing to engage in a series of lawsuits over the issue, came to an out-of-court agreement in November 1995, leading to Apple making a statement of apology. The engineers on

800-640: The original Apple Macintosh . Fully 32-bit microprocessors such as the HP FOCUS , Motorola 68020 and Intel 80386 were launched in the early to mid 1980s and became dominant by the early 1990s. This generation of personal computers coincided with and enabled the first mass-adoption of the World Wide Web . While 32-bit architectures are still widely-used in specific applications, the PC and server market has moved on to 64 bits with x86-64 and other 64-bit architectures since

832-405: 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 to a platform-agnostic "NuBus world". Typically this meant adding a NuBus controller chip between

864-415: The user didn't have to configure the system, the bane of bus systems up to that point. For instance, with ISA the driver had to be configured not only for the card, but for any memory it required, the interrupts it used, and so on. NuBus required no such configuration, making it one of the first examples of plug-and-play architecture. On the downside, while this flexibility made NuBus much simpler for

896-490: Was " Carl Sagan " , one of the three "fraud" code names ( Pilt Down Man , Cold Fusion , and Carl Sagan) referring to the PowerPC processor pretending to be a 68000 . Though the project name was internal, it was revealed to the public in a 1993 issue of MacWeek . Sagan, worried that the public might interpret this as an endorsement which sullied his name, reportedly contacted Apple and threatened to sue unless they could prove

928-626: Was also 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 the Macintosh II series that made up the professional-level Mac lineup from the late 1980s. It was upgraded to NuBus 90 starting with the Macintosh Quadras and used into the mid-1990s. Early Quadras only supported the 20 MHz rate when two cards were talking to each other, since

960-595: Was expensive during the first decades of 32-bit architectures (the 1960s to the 1980s). Older 32-bit processor families (or simpler, cheaper variants thereof) could therefore have many compromises and limitations in order to cut costs. This could be a 16-bit ALU , for instance, or external (or internal) buses narrower than 32 bits, limiting memory size or demanding more cycles for instruction fetch, execution or write back. Despite this, such processors could be labeled 32-bit , since they still had 32-bit registers and instructions able to manipulate 32-bit quantities. For example,

992-723: Was incorporated into their TI Explorer , also a Lisp Machine . In 1986, Texas Instruments used 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 supporting microprocessors. These NuBus boards were co-processor Lisp Machines for the Apple Macintosh line (the Mac II and Mac Quadras). NuBus

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1024-450: Was succeeded in August 1995 by two new models, the Power Macintosh 7200 and the Power Macintosh 7500 , though sales of the 7100 continued into early 1996. The 7100AV variants include a 2 MB VRAM card with S-Video in/out. The non-AV 7100s have a video card containing 1 MB VRAM which was expandable to 2 MB, and no S-Video in/out capability. Apple did not release a "DOS Compatible" card for

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