MBus is a computer bus designed and implemented by Sun Microsystems for communication between high speed computer system components, such as the central processing unit, motherboard and main memory. SBus is used in the same machines to connect add-on cards to the motherboard.
MBus was first used in Sun's first multiprocessor SPARC-based system, the SPARCserver 600MP series (launched in 1991), and later found use in the SPARCstation 10 and SPARCstation 20 workstations. The bus permits the integration of several microprocessors on a single motherboard, in a multiprocessing configuration with up to eight CPUs packaged in detachable MBus modules. In practice, the number of processors per MBus is limited to four. Single processor systems were also sold that use the MBus protocol internally, but with the CPUs permanently attached to the motherboard to lower manufacturing costs.
MBus specifies a 64-bit datapath, which uses 36-bit physical addressing, giving an address space of 64 GB. The transfer rate is 80 MB/s sustained (320 MB/s peak) at 40 MHz, or 100 MB/s (400 MB/s peak) at 50 MHz. Bus controlling is done by an arbiter. Interrupt, reset, and timeout logic are also specified.
Several related buses were also developed:
XBus is a packet-switched bus used in the SPARCserver 1000, SPARCcenter 2000 and Cray CS6400. This corresponds to the circuit-switched MBus, with identical electrical characteristics and physical form factor but an incompatible signalling protocol.
KBus is a high-speed interconnection system for linking multiple MBuses, used in Solbourne Computer Series 6 and Series 7 computer systems.
The MBus standard was cooperatively developed by Sun and Ross Technology and released in 1991. [1]
Manufacturers who produced computer systems using the MBus included Sun, Ross Technology, Hyundai/Axil, Fujitsu, Solbourne Computer, Tatung, GCS, Auspex, ITRI, ICL, Cray, Amdahl, Themis, DTK and Kamstrup.
Meiko Scientific Ltd. was a British supercomputer company based in Bristol, founded by members of the design team working on the Inmos transputer microprocessor.
HyperTransport (HT), formerly known as Lightning Data Transport, is a technology for interconnection of computer processors. It is a bidirectional serial/parallel high-bandwidth, low-latency point-to-point link that was introduced on April 2, 2001. The HyperTransport Consortium is in charge of promoting and developing HyperTransport technology.
SBus is a computer bus system that was used in most SPARC-based computers from Sun Microsystems and others during the 1990s. It was introduced by Sun in 1989 to be a high-speed bus counterpart to their high-speed SPARC processors, replacing the earlier VMEbus used in their Motorola 68020- and 68030-based systems and early SPARC boxes. When Sun moved to open the SPARC definition in the early 1990s, SBus was likewise standardized and became IEEE-1496. In 1997 Sun started to migrate away from SBus to the Peripheral Component Interconnect (PCI) bus, and today SBus is no longer used.
Sun Enterprise is a range of UNIX server computers produced by Sun Microsystems from 1996 to 2001. The line was launched as the Sun Ultra Enterprise series; the Ultra prefix was dropped around 1998. These systems are based on the 64-bit UltraSPARC microprocessor architecture and related to the contemporary Ultra series of computer workstations. Like the Ultra series, they run Solaris. Various models, from single-processor entry-level servers to large high-end multiprocessor servers were produced. The Enterprise brand was phased out in favor of the Sun Fire model line from 2001 onwards.
The SPARCstation 1 is the first of the SPARCstation series of SPARC-based computer workstations sold by Sun Microsystems. The design originated in 1987 by a Sun spin-off company, UniSun, which was soon re-acquired. The SPARCstation 1 has a distinctive slim enclosure and was first sold in April 1989, with Sun's support ending in 1995.
The SPARCstation, SPARCserver and SPARCcenter product lines are a series of SPARC-based computer workstations and servers in desktop, desk side (pedestal) and rack-based form factor configurations, that were developed and sold by Sun Microsystems.
The Sun Ultra is a discontinued line of workstation and server computers developed and sold by Sun Microsystems, comprising two distinct generations. The original line was introduced in 1995 and discontinued in 2001. This generation was partially replaced by the Sun Blade in 2000 and that line was in itself replaced by the Sun Java Workstation—an AMD Opteron system—in 2004. In sync with the transition to x86-64-architecture processors, in 2005 the Ultra brand was later revived with the launch of the Ultra 20 and Ultra 40, albeit to some confusion, since they were no longer based on UltraSPARC processors.
The SPARCstation 20 or SS20 is a discontinued Sun Microsystems workstation introduced in March 1994 based on the SuperSPARC or hyperSPARC CPU. It is one of the last models in the SPARCstation family of Sun "pizza box" computers, which was superseded by the UltraSPARC design in 1995.
The SPARCstation 10 is a workstation computer made by Sun Microsystems. Announced in May 1992, it was Sun's first desktop multiprocessor. It was later replaced with the SPARCstation 20.
SPARCstation 5 or SS5 is a workstation introduced by Sun Microsystems in March 1994. It is based on the sun4m architecture, and is enclosed in a pizza-box chassis. Sun also offered a SPARCserver 5 without a framebuffer. A simplified, cheaper version of the SS5 was released in February 1995 as the SPARCstation 4. Sun also marketed these same machines under the "Netra" brand, without framebuffers or keyboards and preconfigured with all the requisite software to be used as web servers. An estimated 400,000+ SPARCstation 5s were sold.
Sun-4 is a series of Unix workstations and servers produced by Sun Microsystems, launched in 1987. The original Sun-4 series were VMEbus-based systems similar to the earlier Sun-3 series, but employing microprocessors based on Sun's own SPARC V7 RISC architecture in place of the 68k family processors of previous Sun models.
The Sun386i is a discontinued hybrid UNIX workstation/PC compatible computer system produced by Sun Microsystems, launched in 1988. It is based on the Intel 80386 microprocessor but shares many features with the contemporary Sun-3 series systems.
The Cray Superserver 6400, or CS6400, is a discontinued multiprocessor server computer system produced by Cray Research Superservers, Inc., a subsidiary of Cray Research, and launched in 1993. The CS6400 was also sold as the Amdahl SPARCsummit 6400E.
In computing, the clock multiplier sets the ratio of an internal CPU clock rate to the externally supplied clock. This may be implemented with phase-locked loop (PLL) frequency multiplier circuitry. A CPU with a 10x multiplier will thus see 10 internal cycles for every external clock cycle. For example, a system with an external clock of 100 MHz and a 36x clock multiplier will have an internal CPU clock of 3.6 GHz. The external address and data buses of the CPU also use the external clock as a fundamental timing base; however, they could also employ a (small) multiple of this base frequency to transfer data faster.
The SPARCstation 2, or SS2 is a SPARC workstation computer sold by Sun Microsystems. It is based on the sun4c architecture, and is implemented in a pizza box form factor.
The Sun Microsystems Ultra 80 is a computer workstation that shipped from November 1999 to 2002.
Sun4d is a computer architecture introduced by Sun Microsystems in 1992. It is a development of the earlier Sun-4 architecture, using the XDBus system bus, SuperSPARC processors, and SBus I/O cards. The XDBus was the result of a collaboration between Sun and Xerox; its name comes from an earlier Xerox project, the Xerox Dragon. These were Sun's largest machines to date, and their first attempt at making a mainframe-class server.
The Alpha 21164, also known by its code name, EV5, is a microprocessor developed and fabricated by Digital Equipment Corporation that implemented the Alpha instruction set architecture (ISA). It was introduced in January 1995, succeeding the Alpha 21064A as Digital's flagship microprocessor. It was succeeded by the Alpha 21264 in 1998.
The TurboSPARC is a microprocessor that implements the SPARC V8 instruction set architecture (ISA) developed by Fujitsu Microelectronics, Inc. (FMI), the United States subsidiary of the Japanese multinational information technology equipment and services company Fujitsu Limited located in San Jose, California. It was a low-end microprocessor primarily developed as an upgrade for the Sun Microsystems microSPARC-II-based SPARCstation 5 workstation. It was introduced on 30 September 1996, with a 170 MHz version priced at US$499 in quantities of 1,000. The TurboSPARC was mostly succeeded in the low-end SPARC market by the UltraSPARC IIi in late 1997, but remained available.
The SuperSPARC is a microprocessor that implements the SPARC V8 instruction set architecture (ISA) developed by Sun Microsystems. 33 and 40 MHz versions were introduced in 1992. The SuperSPARC contains 3.1 million transistors. It was fabricated by Texas Instruments (TI) at Miho, Japan in a 0.8 micrometre triple-metal BiCMOS process.