Multibus

Multibus is a bus system for industrial computer systems. It was developed by Intel and standardized as IEEE 796 bus. The development began in the mid 1970s, since the end of 1990 this bus system is rarely used.

Importance

The Multibus specification was important because it was a robust, well-designed industry standard with a relatively large size, so that complex devices could be realized. Many companies presented card cages and housing ago. Other manufactured CPU, memory and peripheral boards. 1982, there were over 100 Multibus board and system manufacturers. Sun Microsystems used Multibus in the workstations Sun 1 and Sun 2 with its own processor, memory, SCSI and graphics adapter and added 3Com Ethernet network adapter, Xylogics SMD controller or Systech 16 -port terminal interfaces for server operation added. Other workstation provider which offered Multibus -based solutions were HP / Apollo and Silicon Graphics IRIS.

Architecture

Multibus is an asynchronous I / O bus which devices assigns different transmission rates, while maximum throughput is ensured. There are 20 address lines, allowing up to 1 MB of Multibus memory and 1 MB I / O locations can be addressed. Many I / O devices use only the first 64 kB of the address space.

Multibus supports multi - master functionality, which allows the bus with multiple processors and other DMA devices to share.

The standard size was a 12 x 6.75 -inch board with two ejector levers on the front. The board had two buses. The wider P1- bus equivalent of the pin assignment of the multi-bus specification. A second narrow P2 bus was defined as a separate bus.

Multibus standard

  • Multibus system bus - adopted as the IEEE 796
  • ISBX (I / O expansion bus) - adopted as the IEEE P959
  • ILBX ( Execution Bus)
  • Multi Channel I / O bus

Versions

Multibus I

IEEE -796: Microcomputer System Bus (Intel 1974). Posted.

  • IEC 796-1:1990 Microprocessor system bus 8- bit and 16 -bit data ( MULTIBUS I) - Part 1: Functional description with electrical and timing specifications
  • IEC 796-2:1990 Microprocessor system bus 8- bit and 16 -bit data ( MULTIBUS I) - Part 2: Mechanical and pin descriptions for the system bus configuration, with edge connectors ( direct)
  • IEC 796-3:1990 Microprocessor system BUS I, 8-bit and 16 -bit data ( MULTIBUS I) - Part 3: Mechanical and pin descriptions for the Euro card configuration with pin and socket (indirect ) connectors

Multibus II

IEEE -1296 bus 32-bit/10MHz, with 40MB / s Card Size 3U x 220mm and 6U x 220mm. The cards are larger than VME Euro Card ( 3U/6U x 160mm ). Uses TTL gates for driver and rear connector DIN 41612 type C IEEE -STD -1296: High- performance synchronous 32 -bit bus: Multibus II, (1987, 1994). also ISO / IEC 10861st

  • ISO / IEC 10861:1994 Information technology - Microprocessor systems- high- performance synchronous 32 -bit bus: Multibus II

Use

Multibus II devices under Intel's iRMX operating system can be used in systems of the central line of the London Underground supplied by Westinghouse (now Invensys ). The Oslo T-bane uses a similar but simpler Westinghouse system.

Hewlett-Packard Apollo Computer RMX (operating system)
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