Marathon Technology this week will update its Windows server clustering and failover package with a software-only version.The software-based Endurance Virtual FTserver will replace Marathon\u2019s previous hardware product. The new product runs on Microsoft Windows.\u201cIt is pretty cool because it offers more flexibility to customers in how they deploy the system,\u201d says Jamie Gruener, senior analyst for the Yankee Group. \u201cBefore, customers had to buy the proprietary hardware platform at a premium cost.\u201dFormerly, Marathon used proprietary network adapters to interconnect the servers. The company claims customers like CNN, United Airlines, Tyco and Abbott Laboratories.Virtual FTserver 6.0 supports Microsoft Windows Server 2000 and 2003 and Intel Pentium 4-based single- as well as dual-processor servers. It also supports IBM\u2019s BladeCenter HS20, a dual-processor blade.Virtual FTserver has a continuous-server option. Two servers interconnect via Gigabit Ethernet adapters and operate in lockstep. Each server, called a CoServer, has redundant paths to the other. As data is written to the drive of one server it is concurrently written to the drive of the other server. If one server fails, the other server can continue without interruption. The two CoServers appear to the network, operating system and users as a single system.Each server must be identically configured to use the Marathon technology.Servers can be placed as much as several hundred meters apart. In the fourth quarter of this year, Marathon will announce a long-distance disaster recovery option, which will allow the CoServers to be several hundred miles apart.Marathon\u2019s technology competes with that of Stratus, which also bundles industry-standard servers into fault-tolerant pairs.A single-processor version of Virtual FTserver starts at $5,000. The dual-processor version is $16,000. Both are available now.