Multibus

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Intel iSBC 386/116 Multibus II single board computer with A82389 from VLSI as multibus controller
VLSI VL82C389-GC Multibus II controller from 1987

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

meaning

The Multibus specification was important because it was a robust, well-thought-out industrial standard with a relatively large design so that complex devices could also be implemented. Many companies made card cages and cases . Others produced CPU , memory and peripheral boards. In 1982 there were over 100 multibus board and system manufacturers. Sun Microsystems used Multibus in the work stations 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 the server operating added. Other workstation vendors offering multibus-based solutions were HP / Apollo and Silicon Graphics IRIS.

architecture

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

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

The standard size was a 12 × 6.75 inch board with 2 ejector levers on the front. The board had 2 buses. The pin assignment of the wider P1 bus corresponded to the multibus specification. A second narrow P2 bus was defined as a separate bus.

Multibus standard

  • Multibus System Bus - adopted as IEEE 796
  • iSBX (I / O Expansion Bus) - adopted as IEEE P959
  • iLBX (Execution Bus)
  • Multichannel I / O bus

Versions

Multibus I

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

  • 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 Eurocard configuration with pin and socket (indirect) connectors

Multibus II

IEEE-1296 32-bit / 10 MHz bus, with 40 MB / s. Card size 3U x 220 mm and 6U x 220 mm. The cards are larger than VME-Eurocard (3U / 6U x 160 mm). Uses TTL gates for drivers and rear connectors according to DIN41612 type C. IEEE-STD-1296: High-performance synchronous 32-bit bus: MULTIBUS II, (1987, 1994). also ISO / IEC 10861.

  • ISO / IEC 10861: 1994 Information technology — Microprocessor systems — High-performance synchronous 32-bit bus: MULTIBUS II

use

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

See also

Individual evidence

  1. ↑ IEEE standard microcomputer system bus . In: ANSI / IEEE Std 796-1983 . 1983, p. 1-46 , doi : 10.1109 / IEEESTD.1983.81701 .
  2. ^ Andreas Bechtolsheim, Forest Baskett, Vaughan Pratt: The SUN Workstation Architecture . Stanford University Computer systems Laboratory Technical Report No. 229, March 1982.
  3. ↑ James W. Birdsall: The Sun Hardware Reference ( Memento March 3, 2009 in the Internet Archive ).
  4. ↑ HP / APOLLO SYSTEMS INFORMATION ( Memento from June 8, 2010 in the Internet Archive )
  5. ↑ Silicon Graphics IRIS 2000/3000 FAQ
  6. ^ Sun 68000 Board User's Manual, Sun Microsystems, Inc, February 1933, Revision B

Web links