provides 32-bit external buses. Launched in 1989, the V80 (μPD70832) is the culmination of the series: having on-chip caches, a branch predictor, and less reliance on microcode for complex operations. Software The operating systems developed for the V60-V80 series are generally oriented toward real-time operations. Several OSs were ported to the series, including real-time versions of Unix and I‑TRON. Because the V60/V70 was used in various Japanese arcade games, their instruction set architecture is emulated in the MAME CPU simulator. The latest open-source code is available from the GitHub repository. FRM All three processors have the FRM (Functional Redundancy Monitoring) synchronous multiple modular lockstep mechanism, which enables fault-tolerant computer systems. It requires multiple devices of the same model, one of which then operates in "master mode", while the other devices listen to the master device, in "checker mode". If two or more devices simultaneously output different results via their "fault output" pins, a majority-voting decision can be taken by external circuits. In addition, a recovery method for the mismatched instruction—either "roll-back by retry" or "roll-forward by exception"—can be selected via an external pin. V60 The work on V60 processor began in 1982 with about 250 engineers under the leadership of Yoichi Yano, and the processor debuted in February 1986. It had a six-stage pipeline, built-in memory-management unit, and floating-point arithmetic. It was manufactured using a two-layer aluminum metal CMOS process technology, under a 1.5 μm design rule, to implement 375,000 transistors on a die. It operates at 5 V and was initially packaged in a 68-pin PGA. The first version ran at 16 MHz and attained 3.5 MIPS. Its sample price at launch was set at ¥100,000 ($588.23). It entered full-scale production in August 1986. Sega employed this processor for most of its arcade game sets in the 1990s; both the Sega System 32 and the Sega Model 1 architectures used V60 as their main CPU. (The latter used the lower-cost μPD70615 variant, which doesn't implement V20/V30 emulation and FRM.) The V60 was also used as the main CPU in the SSV arcade architecture—so named because it was developed jointly by Seta, Sammy, and Visco. Sega originally considered using a 16 MHz V60 as the basis for its Sega Saturn console; but after receiving word that the PlayStation employed a 33.8 MHz MIPS R3000A processor, instead chose the dual-SH-2 design for the production model. In 1988, NEC released a kit