Data communications through a host fibre channel adapter

Data communications through a host Fiber Channel adapter ('HFCA') implemented with a computer that includes two or more logical partitions, each logical partition including a separate instance of an operating system, each instance of an operating system including an instance of a low-level, switched fabric input/output ('I/O') library, including establishing, in the HFCA by instances of the I/O library in two or more logical partitions and by the hypervisor, separate logical Fiber Channel adapters ('LFCAs') for at least two of the logical partitions, each LFCA including an association of an LFCA identifier with at least one range of I/O memory addresses in the address space of a logical partition and transferring, at the behest of application programs in the two or more logical partitions, data between the RAM of the logical partitions and the data storage devices through the LFCAs, the HFCA, and the Fiber Channel fabric.