Controlling the initiation of logical systems in a data processing system with logical processor facility

In a computer system that has one or more primary processing units processing user tasks and at least one auxiliary processing unit servicing the primary processing units, feature control is performed by storing a authorization code in the auxiliary processing unit. When an operation to change the feature of the computer system is initiated, a signal, including a key code, is sent to the auxiliary processing unit. The auxiliary processing unit checks the key code against the authorization code, and enables the operation if the check is successful.