IOCP and system generation of a VM operating system

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You must define your I/O configuration to the hardware and conditionally to VM. When you perform an initial program load (IPL) of VM, VM creates its software I/O configuration by sensing the devices in the hardware I/O configuration. If all the devices return all the information VM needs, VM completes its software I/O configuration. If not, you must specify this information in the system configuration file.

To define the devices in your I/O configuration that VM cannot sense, use a set of I/O statements for your VM operating system. Use the system configuration file (SYSTEM CONFIG) on the parm disk.

When you perform an IPL of VM, VM uses a combination of the system configuration file and the devices it senses during IPL to define the I/O configuration to the operating system. VM also updates its software I/O configuration by sensing devices when they are varied online or initialized.

To define your I/O configuration to hardware, you use a set of I/O statements in an IOCP file. When you enter the IOCP command, the IOCP program uses the I/O statements in the IOCP file to define the I/O configuration to the CPC.

For more information about performing these tasks, see Running the VM version of IOCP. Figure 1 shows an overview of the processing performed by the VM version of IOCP.

Figure 1. Overview of VM version of IOCP
this graphic displays the overview of vm version of iocp
  1. Use the system configuration file (SYSTEM CONFIG) to define to the system control program those devices in the I/O configuration that VM cannot sense.
  2. The input file contains the IOCP statements that define the I/O configuration to IOCP.
  3. IOCP processes the IOCP statements, generates an IOCDS, produces reports, and, when requested, writes the generated IOCDS to the Support Element hard disk.
  4. The configuration reports allow you to check the I/O configuration as defined in the IOCDSs.
  5. The IOCDSs reside on the Support Element hard disk. At power-on reset, the Support Element loads the I/O configuration data into the hardware system area (HSA). (Afterward, the I/O subsystem uses the data in the hardware system area (HSA) to control I/O requests.)