摘要 |
A data processing system comprising at least two operating systems (OS1, OS2) for virtual machines, a supervisory operating system, i.e., a control program (CP) for controlling the operating systems, control registers (CR0, CR1, ---) and an extended control register (ECR) having a special bit. When a control register operating instruction (LCTL or STCTL) is executed by one of the operating systems, the special bit has a first value and the operating system directly accesses the control register. When the other of the operating systems attempts to execute such a control register operating instruction, the special bit has a second value and an interruption is generated in the supervisory operating system.
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