Crawley, West Sussex-based Bonar August Systems Ltd – the subsidiary of Low and Bonar Plc that arose from the ashes of fault tolerant supermicro manufacturer August Systems Inc – has launched its first general purpose commercial computer system, the CS3000. The machine, which has been in development since 1985 uses triplicated 68020 processors, VMEbus and two operating system kernels: the pSOS real-time system from Plessey and a source compatible Unix environment. The new machine uses the majority voting system where the three processors compare results and in the rare occasions when one differs from the other two, the majority is taken. A triplicated fault-tolerant clock ensures synchronisation of the three processors, and implementation of the comparison code in hardware rather than software as in the first generation August systems so the comparison process does not impact performance. If a fault shows up, the processor generating it is isolated, and the system automatically falls back to Two-Way Compare between the two surving processors, which can only detect that a fault has occurred, not which processor generated it. And if a second processor fails, it can continue working on the surviving one, signalling at each point that a failure has occurred. Interface cards connect a triplicated bus to VMEbus input-output subsystems, and other buses can also be accomodated. According to Bonar, the approach offers higher reliability at a lower cost than the traditional approaches of dual and hot standby systems: any element can be replaced while the system is on-line, with no performance impact, since the effective performance is only that of one processor anyway. Target applications are real-time tasks such as communications and switching systems, air traffic control, industrial control and defence, although standard Unix application software can also be used on the system. The CS3000 is rated at 2 MIPS, and offers 32Mb memory and a range of storage and communications interfaces via the VMEbus. Systems may be configured with one or two processing units, up to eight input output bus adaptor boards and input-output chassis. The company gave no prices for the new machine. Bonar August Systems is one of several businesses put up for sale last month by Low & Bonar and reports that the announcement that the computer company was available had generated much more interest than anyone there had expected.