The AN/UYK-43 was the standard 32-bit computer of the United States Navy for surface ship and submarine platforms, starting in 1984.[1] Some 1250 units had been delivered through 2000. The size of a refrigerator, it replaced the older AN/UYK-7, both built by UNISYS and shared the same instruction set.[2] An enhancement to the UYK-43, the Open Systems Module (OSM), allows up to six VMEbus Type 6U commercial off-the-shelf (COTS) cards to be installed in a UYK-43 enclosure.