Fault-tolerant server specialist Stratus launched the second member of its new range of Intel Xeon servers in September. Ground-breaking new rollback software for the system will follow next year, designed to make it easier for companies to patch servers.

The Stratus ftServer 4300 comes with one or two 3.2 GHz processors, each with a 1MB Level 2 cache and an 800MHz front-side bus. Designed to run the Microsoft Windows 2003 Server operating system, the server can be fitted with up to 8GB of memory. The firm is also developing a Linux-system for enterprises, but has not said when it will go on sale.

Unlike other server systems that contain one complete server in each chassis or on each blade, Stratus servers are built with duplicated redundant hardware components, including two sets of pro- cessors, memory and disks. So, a dual-CPU 4300 would actually have four Intel Xeon processors.

Normally the two "server halves" run in lock step so that one can carry on working in the event of a single hardware fault. However, a  a new software capability due next year will enable IT professionals to turn off the lock-step operation, which will allow them to upgrade software on one half of the server without affecting the other half.

"Pressures on IT departments for zero downtime mean that people don't have enough time for software upgrades," said Andy Bailey of Stratus. "The Active Upgrade facility will be used primarily to minimise planned downtime of Windows systems. It makes the system appear as two individual machines, to which you can apply an upgrade to one," he added.

Bailey said there will also be a facility that allows administrators to back out of the operation if necessary, and another that lets them bring the two halves into synchronisation after a successful upgrade.

"This capability is primarily for Windows hot-patching, but could also be used to patch some other applications such as Microsoft SQL Server," Bailey added.