True SAN-wide interoperability requires ability to accommodate subtle differences in communication protocols, timing, and device behavior from countless combinations of vendors and versions --- one of the reasons that most interoperable SANs are single-vendor. For example, failover among different systems is prevented by incompatible behavior among host and storage systems. Resolution typically requires modification of drivers and software, which is difficult to achieve with designs that depend on third-party drivers. All software and drivers for the Vicom engine have been developed by Vicom. The result: Vicom delivers open-SAN compatibility, even as vendors release new software and systems.