Analysis of information sources in references of the Wikipedia article "VM (operating system)" in English language version.
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The Hypervisor concept was relatively simple. It consisted of an addendum to the emulator program and a hardware modification on a Model 65 having a compatibility feature. The hardware modification divided the Model 65 into partitions, each addressable from 0-n. The program addendum, having overlaid the system Program Status Words (PSW) with its own, became the interrupt handler for the entire system. After determining which partition had initiated the event causing the interrupt, control was transferred accordingly. The Hypervisor required dedicated I/O devices fore each partition and, because of this, the I/O configurations were usually quite large, and, therefore, prohibitive to the majority of uses.
The Hypervisor concept was relatively simple. It consisted of an addendum to the emulator program and a hardware modification on a Model 65 having a compatibility feature. The hardware modification divided the Model 65 into partitions, each addressable from 0-n. The program addendum, having overlaid the system Program Status Words (PSW) with its own, became the interrupt handler for the entire system. After determining which partition had initiated the event causing the interrupt, control was transferred accordingly. The Hypervisor required dedicated I/O devices fore each partition and, because of this, the I/O configurations were usually quite large, and, therefore, prohibitive to the majority of uses.
In a real processor, the DIAGNOSE instruction performs processor-dependent diagnostic functions. In a virtual machine, you use the DIAGNOSE interface to request that CP perform services for your virtual machine. When your virtual machine attempts to execute a DIAGNOSE instruction, control is returned to CP. CP uses information provided in the code portion of the instruction to determine what service it should perform. Once this service is provided, control returns to the virtual machine.
The Hypervisor concept was relatively simple. It consisted of an addendum to the emulator program and a hardware modification on a Model 65 having a compatibility feature. The hardware modification divided the Model 65 into partitions, each addressable from 0-n. The program addendum, having overlaid the system Program Status Words (PSW) with its own, became the interrupt handler for the entire system. After determining which partition had initiated the event causing the interrupt, control was transferred accordingly. The Hypervisor required dedicated I/O devices fore each partition and, because of this, the I/O configurations were usually quite large, and, therefore, prohibitive to the majority of uses.
In a real processor, the DIAGNOSE instruction performs processor-dependent diagnostic functions. In a virtual machine, you use the DIAGNOSE interface to request that CP perform services for your virtual machine. When your virtual machine attempts to execute a DIAGNOSE instruction, control is returned to CP. CP uses information provided in the code portion of the instruction to determine what service it should perform. Once this service is provided, control returns to the virtual machine.
