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The Pluribus〔''Pluribus'' is the ablative plural of the Latin word for "more" or "above."〕 multiprocessor was an early multi-processor computer designed by BBN for use as a packet switch in the ARPANET. Its design later influenced the BBN Butterfly computer. The Pluribus had its beginnings in 1972 when the need for a second-generation interface message processor (IMP) became apparent. At that time, the BBN had already installed IMPs at more than thirty-five ARPANET sites. These IMPs were Honeywell 316 and 516 minicomputers. The network was growing rapidly in several dimensions: number of nodes, hosts, and terminals; volume of traffic; and geographic coverage (including plans, now realized, for satellite extensions to Europe and Hawaii). A goal was established to design a modular machine which, at its lower end, would be smaller and less expensive than the 316's and 516's while being expandable in capacity to provide ten times the bandwidth of, and capable of servicing five times as many input-output (I/O) devices as, the 516. Related goals included greater memory addressing capability and increased reliability. The designers decided on a multiprocessor approach because of its promising potential for modularity, for cost per performance advantages, for reliability, and because the IMP packet switch algorithms were clearly suitable for parallel processing by independent processors. == Hardware == A Pluribus consisted of two or more standard 19" electronic equipment racks, each divided into four bays. Each bay contained a backplane bus and an independent power supply. A bay might contain a processor bus, a shared memory bus, or an I/O bus. Custom-built bus couplers connected the bays to one another so that the processors could reach the shared memory and the I/O devices. A 6-processor Pluribus was used as a network switch to interconnect BBN's five Tenex/"Twenex" timesharing systems along with 378 terminals on direct serial and dial-in modem lines. The Pluribus used the Lockheed SUE as its processor. The SUE was similar to DEC's PDP-11. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pluribus」の詳細全文を読む スポンサード リンク
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