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Futurebus (IEEE 896) is a computer bus standard designed to replace all local bus connections in a computer, including the CPU, plug-in cards, and even some LAN links between machines. The project started in 1979 and was completed in 1987, but then went through a redesign until 1994. It has seen little real-world use, although custom implementations are still designed.
In the late 1970s, VMEbus was faster than the parts plugged into it. It can connect a CPU and RAM to VME on separate cards to build a computer. However, as the speed of the CPUs and RAM rapidly increased, Futurebus created a successor to VMEbus using asynchronous links. Though the ability to have several cards in the system as "masters", allowing Futurebus to build multiprocessor machines, required some form of "distributed arbitration" to allow the various cards to gain access to the bus at any point, as opposed to VME, which put a single master in slot 0 with overall control.
Typical IEEE standards start with a company building a device, then submitting it to the IEEE for the standardization effort. In the case of Futurebus, the whole system was being designed during the standardization effort. It took eight years before the specification was finally agreed on in 1987. Tektronix did make a few workstations based on Futurebus. [1] It took another four years for the Futurebus+ Standard to be released. The IEEE 896 committee later split from the IEEE Microcomputer Standards Committee and formed the IEEE Bus Architecture Standards Committee (BASC).
Futurebus+ transceivers that meet the IEEE Standard 1194.1-1991 Backplane Transceiver Logic (BTL) standard are still made by Texas Instruments. Futurebus+ was used as the I/O bus in the DEC 4000 AXP and DEC 10000 AXP systems. Futurebus+ FDDI boards are still supported in the OpenVMS operating system.
Futurebus is described in the following IEEE standards:
Futurebus systems were implemented with 9U×280 Eurocard mechanics using 96-pin DIN connectors, resulting in a backplane that supported both 16- and 32-bit bus widths. Futurebus+ boards are 12SU×12SU Hard Metric size defined in the IEEE 1301 standards.
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.
Alpha is a 64-bit reduced instruction set computer (RISC) instruction set architecture (ISA) developed by Digital Equipment Corporation (DEC). Alpha was designed to replace 32-bit VAX complex instruction set computers (CISC) and to be a highly competitive RISC processor for Unix workstations and similar markets.
Eurocard is an IEEE standard format for printed circuit board (PCB) cards that can be plugged together into a standard chassis which, in turn, can be mounted in a 19-inch rack. The chassis consists of a series of slotted card guides on the top and bottom, into which the cards are slid so they stand on end, like books on a shelf. At the spine of each card is one or more connectors which plug into mating connectors on a backplane that closes the rear of the chassis.
In computing, an expansion card is a printed circuit board that can be inserted into an electrical connector, or expansion slot on a computer's motherboard to add functionality to a computer system. Sometimes the design of the computer's case and motherboard involves placing most of these slots onto a separate, removable card. Typically such cards are referred to as a riser card in part because they project upward from the board and allow expansion cards to be placed above and parallel to the motherboard.
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.
VMEbus is a computer bus standard physically based on Eurocard sizes.
The S-100 bus or Altair bus, IEEE 696-1983(inactive-withdrawn), is an early computer bus designed in 1974 as a part of the Altair 8800. The S-100 bus was the first industry standard expansion bus for the microcomputer industry. S-100 computers, consisting of processor and peripheral cards, were produced by a number of manufacturers. The S-100 bus formed the basis for homebrew computers whose builders implemented drivers for CP/M and MP/M. These S-100 microcomputers ran the gamut from hobbyist toy to small business workstation and were common in early home computers until the advent of the IBM PC.
The Scalable Coherent Interface or Scalable Coherent Interconnect (SCI), is a high-speed interconnect standard for shared memory multiprocessing and message passing. The goal was to scale well, provide system-wide memory coherence and a simple interface; i.e. a standard to replace existing buses in multiprocessor systems with one with no inherent scalability and performance limitations.
CompactPCI is a computer bus interconnect for industrial computers, combining a Eurocard-type connector and PCI signaling and protocols. Boards are standardized to 3U or 6U sizes, and are typically interconnected via a passive backplane. The connector pin assignments are standardized by the PICMG US and PICMG Europe organizations. The connectors and the electrical rules allow for eight boards in a PCI segment. Multiple bus segments are allowed with bridges.
A system bus is a single computer bus that connects the major components of a computer system, combining the functions of a data bus to carry information, an address bus to determine where it should be sent or read from, and a control bus to determine its operation. The technique was developed to reduce costs and improve modularity, and although popular in the 1970s and 1980s, more modern computers use a variety of separate buses adapted to more specific needs.
VME eXtensions for instrumentation bus refers to standards for automated test based upon VMEbus. VXI defines additional bus lines for timing and triggering as well as mechanical requirements and standard protocols for configuration, message-based communication, multi-chassis extension, and other features. In 2004, the 2eVME extension was added to the VXI bus specification, giving it a maximum data rate of 160 MB/s.
Multibus is a computer bus standard used in industrial systems. It was developed by Intel Corporation and was adopted as the IEEE 796 bus.
The STEbus is a non-proprietary, processor-independent, computer bus with 8 data lines and 20 address lines. It was popular for industrial control systems in the late 1980s and early 1990s before the ubiquitous IBM PC dominated this market. STE stands for STandard Eurocard.
VPX, also known as VITA 46, is a set of standards for connecting components of a computer, commonly used by defense contractors. Some are ANSI standards such as ANSI/VITA 46.0–2019. VPX provides VMEbus-based systems with support for switched fabrics over a new high speed connector. Defined by the VMEbus International Trade Association (VITA) working group starting in 2003, it was first demonstrated in 2004, and became an ANSI standard in 2007.
DIN 41612 was a DIN standard for electrical connectors that are widely used in rack based electrical systems. Standardisation of the connectors is a pre-requisite for open systems, where users expect components from different suppliers to operate together. The most widely known use of DIN 41612 connectors is in the VMEbus and NuBus systems. The standard has withdrawn in favor of international standards IEC 60603-2 and EN 60603-2.
The DEC 4000 AXP is a series of departmental server computers developed and manufactured by Digital Equipment Corporation introduced on 10 November 1992. These systems formed part of the first generation of systems based on the 64-bit Alpha AXP architecture, and at the time of introduction, ran Digital's OpenVMS AXP or OSF/1 AXP operating systems.
M-Modules are a mezzanine standard mainly used in industrial computers. Being mezzanines, they are always plugged on a carrier printed circuit board (PCB) that supports this format. The modules communicate with their carrier over a dedicated bus, and can have all kinds of special functions.
CompactPCI Serial is an industrial standard for modular computer systems. It is based on the established PICMG 2.0 CompactPCI standard, which uses the parallel PCI bus for communication among a system's card components. In contrast to this, CompactPCI Serial uses only serial point-to-point connections. CompactPCI Serial was officially adopted by the PCI Industrial Computer Manufacturers Group PICMG as PICMG CPCI-S.0 CompactPCI Serial in March 2011. Its mechanical concept is based on the proven standards of IEEE 1101-1-1998 and IEEE 1101-10-1996. CompactPCI Serial includes different connectors that permit very high data rates. The new technology standard succeeding parallel CompactPCI comprises another specification called PICMG 2.30 CompactPCI PlusIO. This is why CompactPCI Serial and CompactPCI PlusIO as a whole were also called CompactPCI Plus. PICMG's first working title of CompactPCI Serial was CPLUS.0. CompactPCI Serial backplanes and chassis are developed by Schroff, Elmа, and Pixus Technologies companies, as for the CompactPCI Serial board level electronics – they are developed by MEN Mikro Elektronik, Fastwel, EKF, Emerson Embedded Computing, ADLINK, and Kontron.
The Europe Card Bus is a computer bus developed in 1977 by the company Kontron, mainly for the 8-bit Zilog Z80, Intel 8080 and Intel 8085 microprocessor families.
Modular crate electronics are a general type of electronics and support infrastructure commonly used for trigger electronics and data acquisition in particle detectors. These types of electronics are common in such detectors because all the electronic pathways are made by discrete physical cables connecting together logic blocks on the fronts of modules. This allows circuits to be designed, built, tested, and deployed very quickly as an experiment is being put together. Then the modules can all be removed and used again when the experiment is done.