WinSURE is a reliability analysis program used for calculating upper and lower bounds on for the operational and death state probabilities for a large class of semi-Markov models. The program is especially suited for the analysis of fault-tolerant reconfigurable systems. The calculated bounds are close enough (usually within 5 percent of each other) for use in reliability studies of ultra-reliable computer systems. The SURE bounding theorems have algebraic solutions and are consequently computationally efficient even for large and complex systems. SURE can optionally regard a specified parameter as a variable over a range of values, enabling an automatic sensitivity analysis.

The WinSURE program is written in Java and has been tested on Linux, Mac, and Windows operating systems.