MBus (SPARC)
| Industry | Computer hardware |
|---|---|
| Founded | February 24, 1982 |
| Headquarters | Santa Clara, California , United States |
| Products | Computer hardware, computer buses (e.g., MBus) |
MBus is a computer bus engineered by Sun Microsystems to facilitate rapid data exchange among critical system elements such as the central processing unit, motherboard, and main memory. Within the same architecture, the SBus serves to connect peripheral expansion cards to the motherboard.
Initially launched with Sun's pioneering multiprocessor SPARC platform, the SPARCserver 600MP series in 1991, MBus was subsequently incorporated into the SPARCstation 10 and SPARCstation 20 models. It supports multiprocessing setups accommodating up to eight CPUs via removable MBus modules, though practical implementations usually cap at four processors per bus. In single-CPU configurations using MBus protocols, processors are commonly soldered directly onto the motherboard to minimize expenses.
The MBus architecture includes a 64-bit data path accompanied by 36-bit physical addressing, allowing access to a 64 GB memory range. It achieves sustained data throughput of 80 MB/s (with peak rates up to 320 MB/s) at a clock speed of 40 MHz, and 100 MB/s sustained (400 MB/s peak) when operating at 50 MHz. Arbitration controls the bus operations, integrating interrupt handling, reset functions, and timeout mechanisms.
XBus
The XBus is a packet-based bus utilized in systems like the SPARCserver 1000, SPARCcenter 2000, and Cray CS6400. While it shares electrical properties and physical dimensions with MBus, it employs a signaling protocol that is not compatible.
KBus
KBus acts as a high-performance interconnect that links multiple MBuses together and is implemented in Solbourne Computer Series 6 and Series 7 machines.
History
The MBus standard emerged in 1991 through a collaboration between Sun Microsystems and Ross Technology.
Adopters of MBus-compatible systems included manufacturers such as Sun, Ross Technology, Hyundai/Axil, Fujitsu, Solbourne Computer, Tatung, GCS, Auspex Systems, ITRI, ICL, Cray, Amdahl, Themis Computer, DTK Computer, and Kamstrup.
See also
References