For years, specialist "fault-tolerant" server makers have doubled up hardware to make servers more reliable. Now the approach is being applied to a new area where reliability is needed -- the Intel server running Windows applications. On 10 March, veteran fault-tolerant vendor Stratus will launch a rack-mounted, entry-level, fault-tolerant Intel server. Fault tolerance has so far been an expensive option reserved for high-risk businesses such as financial services and telecoms, but users throughout industry are depending more and more on applications like email, running on fallible Windows/Intel servers. As the cost of such failures gets higher, fault-tolerant hardware is becoming a serious option outside the financial sector and the datacentre. Stratus' ftServer 3300, a 4U unit, comprised of two separate processor units and two I/O units, will be launched on 10 March at the StratusWorld event in Las Vegas. It will replace Stratus' former entry-level unit, the 3200 system jointly designed by NEC, with a machine that is twice as fast and half the size for the same price. The system is intended to support critical Windows application servers, and designed to be comparable in cost with a two-node failover cluster, according to David Chalmers, director of products and technology EMEA, for Stratus: "The hardware costs about 15 to 20 percent more, but the software costs are lower [since Microsoft does not charge a fee for the dual processors running in lockstep] and the people costs are far less since our fault tolerance is transparent to the OS." A ft3300 will cost £15,000 to £25,000 depending on specifications, said Chalmers: "Why pay more for something less reliable?" Stratus has been shipping Intel-based, fault-tolerant servers designed to run Windows for more than a year. "We have sold 1,500 units worldwide," said Chalmers. As well as these direct sales, resellers (led by NEC in Japan) have sold a similar number, he said. Stratus claims to have reached the mythical "five nines" reliability, with systems that are up for 99.9994 percent of the time -- equating to about a minute of downtime in a year. The system will run Windows Server 2003 -- and users can buy a "downgrade rights" licence that allows them to run Windows 2000 until they (and Microsoft) are ready to move to Windows Server 2003. "Windows 2003 is a big change for fault-tolerant systems," said Chalmers. "Problems with device drivers have been removed." After a chequered career in which it was bought by Ascend and then torn in two by Ascend's next owner, Lucent, Stratus is now united under one roof, with backing from venture fund Investcorp. The move to Intel processors was necessitated by questions over the future of HP's PA chips, on which its legacy systems are based. While Intel-based sales are expected to grow, the company believes that its PA systems will be in demand for some time. "Fault-tolerant customers are sticky customers," said Chalmers. "If it ain't broke they won't fix it. Many of them are putting our Intel-based systems around previous Stratus systems."