IUCV (Inter User Communication Vehicle) is a data transfer mechanism in IBM VM line of operating systems.
IUCV allows establishing point to point communication channels, either between 2 virtual machines or between a virtual machine and hypervisor services. In effect, IUCV provides a form of message-based interaction between virtual machines that anticipated the client/server interaction between network connected physical machines that emerged later on distributed systems.
IUCV is implemented by CP (the VM hypervisor) and controls all aspects of session establishments, message passing and flow control.
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