This is a uni-processor (UP) or multi-processor (MP) virtual machine that has a coupled connection to a CF Service Machine using the software simulation of the message facility. This virtual machine is running an operating system that supports the coupling facility, such as MVS™.

The system administrator must define a user ID for each coupled guest that will run under z/VM®. To define each user ID as a coupled guest, the CFUSER operand must be specified on the OPTION directory control statement for each virtual machine. The CFUSER operand defines the virtual machine as a coupled guest and allows it to connect to a CF Service Machine.

Any number of coupled guests can be defined, and each coupled guest can establish a coupled connection with up to eight different CF Service Machines concurrently.