Using Configuration Files

The system configuration file and the logo configuration file, as well as any files that these configuration files imbed, are stored on the parm disk. The parm disk is a regular CMS-formatted minidisk that you identify to CP by writing an allocation map on the IPL volume marking the location of the minidisk. The parm disk is accessed at IPL time, and configuration information is read from the configuration files stored on the disk.

To place configuration information on the parm disk, you must do the following:

  1. Choose a CMS-formatted minidisk on the IPL volume on which you plan to place configuration files. (If the minidisk is not CMS-formatted, the system will enter a wait state when you try to use it.)
  2. Run the ICKDSF utility to rewrite the allocation map on the IPL volume to mark a parm disk extent that covers the location of the minidisk. See the Device Support Facilities User's Guide and Reference for details on formatting and allocating DASD volumes using ICKDSF.
  3. Place a system configuration file (called SYSTEM CONFIG by default), a logo configuration file (called LOGO CONFIG by default), or both, on the parm disk. Other names can be used for these files. You can specify the name of the system configuration file when you IPL. For more information, see Passing IPL Parameters in z/VM: System Operation. You can specify a name for the logo configuration file inside the system configuration file. Place any logo picture files on this disk also.
Note: Although the system control file (HCPSYS ASSEMBLE), system real I/O configuration file (HCPRIO ASSEMBLE), and system logo definition file (HCPBOX ASSEMBLE) are still supported, IBM® strongly recommends that you use configuration files to define your system. Using the ASSEMBLE files is more difficult and error-prone, requires availability and knowledge of the necessary level of the IBM High Level Assembler licensed program (or an equivalent product), does not support recent CP enhancements, and requires rebuilding the CP module after making changes.

The HCPSYS ASSEMBLE file supplied with z/VM® contains no system definitions. The supplied HCPRIO ASSEMBLE file contains only an RIOGEN CONS=DYNAMIC macro to indicate that console addresses are defined in the system configuration file. The supplied HCPBOX ASSEMBLE contains default system logos.

For information about the system definition macros, see the z/VM 6.2 edition of this document.

A default SYSTEM CONFIG file is created at installation time. You can update this file or create your own system configuration file using the editor of your choice.

During the IPL process, CP tries to access the first parm disk that is marked in the allocation map on the IPL volume. If there is a parm disk marked, and if the disk locations matching the extent represent a CMS-formatted minidisk, CP attempts to read the system configuration file from the disk.

The format of the system configuration file is described in What You Can Specify in the System Configuration File. If CP finds a file called SYSTEM CONFIG (or the name you specify on IPL), it examines the contents of the file and applies any changes requested in the file to the system configuration. Values defined in the system configuration file override any values defined in HCPSYS ASSEMBLE and HCPRIO ASSEMBLE. If CP finds a file called LOGO CONFIG (or the name defined in the system configuration file), it uses the contents of that file to override all the logo characteristics set in HCPBOX ASSEMBLE.

Before the first prompt, which asks you what method of system initialization you need, the system displays information about the parm disk. After the system is up and running, you can use the QUERY CPLOAD command to find out whether CP accessed a parm disk, and if so, what that disk was.